Tag Archives: A to B 49

A to B 49 cover

A to B 49 – Technology Special!

A to B 49 August 2005, Technology SpecialCutting edge stuff! Whatever your preference in alternative transport, this issue will show you something entirely new. Folding bike? Follow our lightweight Brompton project – 10.9kg in 1997 and 9.5kg today. Electric bike? We can offer a range of 35 miles from a Lithium-ion battery… Gears? Professor Pivot investigates a practical fully automatic gearbox… Recumbents? Giant’s new Revive Spirit is stashed with technology.

We’ve tested the future, and it seems to work reasonably well. Compare today’s technology with that of ten years ago, and nothing would be wildly different – just incrementally better in every way. The next ten years will be much the same. Folding bicycles will continue to get lighter, and electric bicycles will go further and faster. At the moment, it’s all rather expensive, but another lesson of history is that prices usually fall once technology gets established. On a final rather gloomier note – today’s transport environment is much worse than it was ten years ago.Will that trend continue?

A to B 49 Contents

Ezee Lithium Battery

Ezee Lithium-Ion Battery

Ezee Lithium BatteryWe’ve talked before about the energy density of batteries used for bicycle lighting and bicycle motive power.To recap briefly, the battery in a car is a lead-acid device – big, heavy and full of nasty things, but recycleable and reasonably cheap. Batteries like these offer a theoretical energy density of 35 – 50 watt/hours per kilogram (Wh/kg). In practice, taking into account the weight of the cells, casing and wiring, the finished product rarely exceeds 20 – 40 Wh/kg. To get a decent range from such a low-powered battery, it needs to be very heavy – typically 13.4kg for the Powabyke unit.

Technology has long since moved on to the Nickel- Cadmium (NiCd) battery, with a theoretical capacity of 45 – 80Wh/kg – weight for weight, about twice as useful as a lead- acid battery, but full of nasty cadmium, so something of a hazard to the environment.The NiCd has recently been replaced by its more easily recycleable cousin, the Nickel Metal-Hydride, or NiMH battery, currently fitted to around 50% of rechargeable devices worldwide.These batteries have some odd habits, but they recharge relatively fast, and have a theoretical capacity of 60 – 120Wh/kg, which equates to around 40 – 60Wh/kg in practice. Note that although the worst NiMH performance may look similar to the best lead-acid battery, the capacity is measured in a different way, so NiMH and NiCd actually perform better than the bare figures suggest.They also have a much longer service life.


More recently, attention has switched to various kinds of Lithium-ion rechargeable cells.These promise a massive increase in energy density, with theoretical figures of 200 – 700Wh/kg being bandied about in learned papers, but the reality, for the time being at least, is more prosaic. Our first experience with Li-ion technology was the Powabyke experimental cell (A to B 45), which offered just 30Wh/kg, thanks to some ferociously complex internal wiring and a big heavy casing. In the few months since, we’ve tried some more effective technology – typically 73Wh/kg from the Panasonic WiLL battery featured in issue 46, and 69Wh/kg from the similar battery fitted to the Giant Revive in this issue.

“…the battery is 12% lighter and range is increased by nearly 10%…”

Early lithium-ion cells had a tendency to explode, particularly while charging, but a great deal of research has gone into monitoring systems, and alternative electrode chemistry has made them safer and more rugged. Until now, these monitoring systems for the individual cells (a bicycle battery needs up to ten cells) have been crammed into the charger, resulting in lots of wires and a big heavy charger, but miniaturisation has made it possible for the control systems to be fitted inside the battery itself, and the new Ezee Li-ion battery is the first we have tried of this kind.

Ezee bikes are currently supplied with a large, and quite efficient NiMH battery, with an energy density of 57Wh/kg – one of the best figures around.The new battery looks exactly the same, but inside are the electronics to keep everything running happily, and ten Li-ion cells with a capacity some 11% greater than the old battery. Despite the bigger capacity and the complex electronics, the new technology means the battery is 12% lighter than the NiMH, at 4.4kg, against 5.6kg.This results in an energy density of 82Wh/kg – the best we’ve yet tried.And with most of the electronics in the battery, the charger is lighter and easier to use. On the prototype, the charge rate has been set quite low, giving a charge time of nearly five hours, but if testing proceeds smoothly, the unit may be uprated.

For those already using an Ezee Sprint, the technology is fully retrofittable, so you’ll only need to buy the battery and charger to upgrade an older machine.

What do you get?

The lighter battery is obviously a benefit, but more importantly, range is increased by nearly 10% as well.We completed a run on our standard hilly test course of 29.3 miles at an average of no less than 16mph. Our elderly Ezee Forza has a power-hungry US spec: Keeping the assisted speed below the legal limit, we hit 34.9 miles at 14.7mph. That’s a little better than the Powabyke – which is generally considered to give the best range – but from a battery weighing less than a third as much. One slight disadvantage, hinted at by the high road speed, is that the battery runs more or less at full power until the last few hundred metres, before dying almost without warning.

Obviously the lighter battery and greater range make the technology very attractive. And despite the apparent negative aspects of carrying all the electronics around, the charging system seems relatively foolproof against the others we’ve tried.

Those with an interest in chemistry might like to hear that the first generation Li-ion batteries were mostly built around cobalt oxide cathodes, but improved manufacturing methods have made it possible to use manganese oxide, with manganese/titanium oxide on the horizon.Without getting involved with electrons and ionic transfer, all the consumer needs to know is that these are clean, recycleable technologies, and the raw materials are widely available, so prices are expected to fall by 30% in the next year or so.

Any disadvantages? Li-ion cells have been used in mobile phones and laptops for a while now, but despite plenty of lab work, no one is quite sure what will happen in high power, all-weather applications like electric bicycles. Battery life is currently a subject of debate, as is cost, and capacity improvements. Making some very rash predictions, we think performance could well double within five years, giving an electric bike range of up to 60 miles.The related Lithium Polymer battery promises to double the range again, so electric bicycle range of 100 miles, and electric car or motorcycle range of 200 miles seems realistic, but when? Will the technology arrive in time to soften the ‘peak oil’ blow? Only time will tell, but for now, welcome to the future!

Shanghai Ezee Kinetic. UK distributor 50Cycles

A to B 49 – Aug 2005

Hub Gear Conversion

Hub Gear Conversion

Hub Gear ConversionIf you think about it, the quality of a child’s bike is really important. If a child grows up with a heavy, impractical bicycle, he or she starts life with the impression that bicycles are heavy impractical machines.The evidence from the current generation is that apart from dabbling with BMX, the vast majority stop riding bicycles just as soon as they can, and most never return. Rather disturbingly, there’s growing evidence that many in Alexander’s generation will never learn to ride at all.

When Alexander was old enough for a ‘proper’ bike we chose a German-made Puky. Children’s bikes with dynamo lights, a rack and mudguards are common on the Continent, but only the Puky is easily obtainable here, thanks to importer Amba Marketing. By the spring of 2005, our 18-inch wheel example (see A to B 41) had given great service for 18 months and 400 miles, but at six, the boy was growing rapidly, and trying longer rides.The time had come for an upgrade, but not yet to a bigger bike.


…any competent cycle engineering should be able to upgrade…to hub gear operation…

How would we define the perfect bike for a small child? For obvious reasons, it needs to be reasonably fashionable. If everyone else is riding Death-Squad BMX UXB MTBs, with unobtainium gussets and nobble-tooth mud pluggers, pushing the sensible, weedy option can be hard work.The bike also needs to be suitable for road use in all weathers, plus some modest off-roading, and come equipped with user-friendly hub gears, brakes, mudguards and lights. Quite a tall order, really.

Puky sell a range of fully-equipped 20-inch bikes, and a few 18-inch bikes, but none of the smaller machines have gears.The answer was to upgrade what we had, adding a Sturmey Archer S-RC3 hub to Alexander’s Puky 18-1B, producing, one assumes, an 18-3B. The beauty of using this rare hub is that it also comes with a back-pedal operated ‘coaster’ brake. Fitting something like this might sound complicated, but any competent cycle engineer should be able to upgrade a single-speed or derailleur-geared bike to hub gear operation.

Three-speed hubs used to be almost universal in Britain, but the arrival of cheap, sexy-looking derailleurs changed all that, and enclosed hub gears are now generally confined to roadsters and small-wheeled bikes. As we point out on a regular basis, this is most unfortunate. Few adults understand the principles of riding with close-ratio derailleur gears and for children, three gears are more than enough to think about.

Hub gears can be changed whilst stationary, making them ideal in traffic (or for those of a forgetful disposition at any time) and although the number of gears might sound modest in this number/size obsessed age, even the most basic hub provides a decent gear range. The range – for those who aren’t quite sure – is the difference between top and bottom gear. A wide range of gears enables the bike to nip along under a wide range of circumstances.

With Alexander’s friends acquiring MTBs with five or six derailleur gears, we found ourselves trying to explain that a SRAM, Nexus or Sturmey three-speed offers a gear range of around 180%, which is about the same as a cheap six-speed derailleur.There’s a widespread belief that hubs are less efficient, but a three-speed should return efficiency of 94-95%, a figure that a cheap derailleur would be pushed to achieve after a few weeks’ youthful abuse. It also comes with bullet-proof indexing and is almost immune from throwing its chain off.

Hub Gear Conversion


Coaster brakes have never really caught on here, but having seen a child grow up using one, we’re converts, and most parents on the Continent would probably agree.When you’re learning to make hand signals and keeping an eye open for traffic, there’s a lot to be said for controlling the primary The coaster hub looks brake with your feet. For as if it was made for dad, there are 33% fewer the bike. Note the ‘extra’ cables to adjust and spoke holes and rather lubricate.We hope you’re avant–garde spoke pattern convinced.


We won’t bore you with the fitting process – if you know what you’re doing, it’s easy, and if you don’t, we’d recommend visiting a good bike shop. Most of the shops that advertise in A to B can carry out this sort of work, but as usual, the real experts are Bicycle Workshop in Birdy rim will fit the larger 355m (18- West London, who regularly upgrade children’s bikes (and adult cruiser bikes) to this sort of spec. If doing the work yourself, the hub costs £65 with a lever changer, plus £8 for the twistgrip. Expect to add around £35 if the shop does the work for you.

The new hub weighs 400g, so with cables and twistgrip, the weight penalty for upgrading from a single-speed has been about 1kg. Starting with a derailleur, you’ll be removing sprockets, cables, a brake lever and a brake caliper, so the weight will be about the same. Gearing depends on circumstances – we fitted an 18-tooth rear sprocket, giving gears of 26″, 35″ and 47″. Broadly speaking, that’s one gear for the flat, and two hill- climbing options. Bottom gear will tackle 12.5% (1:8), taking care of most of the local hills.

Is the boy pleased with his gears? What boy wouldn’t be pleased with a TSS32 shifter, shiny S-RC3 hub, 178% range, 18-tooth sprocket and a host of other part numbers? At six, life is all about numbers. For Alexander, the back pedal brake is familiar territory of course, but the gears took a few days to get used to. Cycling mileage has since rocketed to about 60 miles a month, and the unusual machine, with its novel lights, rack and gears, seems to be much admired.

You can’t win of course. Alexander knows a thing or two about hubs, and he’s already applying subtle pressure for a five-speed. Sturmey doesn’t make a coaster five-speed, but the indestructible SRAM P5 is available in coaster form…The perfect 20-inch bike?


The Sturmey S-RC3, like most hubs, comes drilled for 36-spokes, but children’s rims – including our rare-in- the-UK 355mm rim – are usually drilled for 20. Its unusual to find 305mm (16-inch) rims drilled for 36-spokes, but a inch) bikes. In the largest 20 and 24-inch sizes, there are plenty of rims and tyres to choose from.To make life difficult, we decided to re-drill the old rim to take 18 spokes, lacing the wheel using alternate spoke holes, braced with a single 13G spoke to prevent the wheel ‘winding up’ under braking.This arrangement would be too frail for an adult bicycle, but for a child weighing 22kg, a new rim and 36-spokes aren’t really necessary. On our single-speed bike, we also needed to stretch the rear drop-outs slightly, but it’s more likely that adjustment would be needed in the other direction on a derailleur bike.

Rim Griddle

Bicycles are responsible for a tiny fraction of transport waste, and people who ride bicycles are renowned hoarders.But most small-wheeled bike commuters will have thrown away a few worn, but otherwise intact wheel rims over the years.They may not be safe to ride on, but there’s no need to throw them away!

Brompton Rim Griddle

Meet the 347mm barbecue griddle.Take one old Brompton front wheel and strip it right down, removing the axle and bearings (you’re bound to find a use for these). Study the spokes: if pre-February 2000, they will be galvanised steel, so you’ll need to fit newer stainless spokes (around £11 per set). Stainless steel spokes will need no more than a thorough clean.

Take the old axle, cut out the centre section and reassemble the two end caps back to back, then re-thread the old spokes to build a two-dimensional wheel, using the new or recycled stainless spokes.You’ll probably need to put spacers (we used 5mm nuts) under the spoke nipples, because the spokes will now be a little long for the job.

Finally, take an old bit of wooden dowel, drill down the middle and put a bolt through the valve hole to fasten the handle to the rim. It would also be sensible to lace wire around the spokes spider’s web fashion to stop chipolatas falling through the gaps, but we prefer the aesthetically pleasing 28-spoke look, and the occasional ashy sausage.

Cost (assuming you re-use old spokes) is zero. And don’t bother with all that charcoal nonsense. Six house bricks, a pile of sticks, and you’re ready to grill. OK, maybe Argos does sell a whole barbecue for £7.99, but that will be rubbish – yours will be a tastefully recycled fashion statement.

PS Those with very few friends could use a 305mm rim, while more gregarious types may need a 406mm.Traditional 26-inch wheels will enable you to cook for the whole street, thus possibly making new friends. An unexpected bonus.

Lightweight Brompton

Superlight Brompton

Superlight Brompton Folding BikeBig strong men sometimes ask us why we put such an emphasis on reducing the weight of folding bikes. If you have to ask the question, you really don’t need to know the answer.Taking weight out of a bicycle has little effect on performance, but a great deal of effect on the ease with which it can be carried.

Many people would be willing to use a folding bike but cannot lift a 14kg (33lb) weight, let alone haul it upstairs or run for a train with it. Get the weight down to a reasonable 12kg, and most people can deal with it. At 10kg, we’re up to, perhaps, 90% of the adult population, and if weight can be pared down to less than 8kg (already feasible, but expensive), the bike becomes practical for almost anyone to carry.Weight reduction is a truly emancipating technology, bringing folding bikes to those previously excluded.You might argue that they still need to be pretty wealthy, but this is really only a state of mind problem. If a high-end folding bike eliminates the need for a second or third family car, a purchase price of £1,000 or so can represent great value for money.This technology is getting less expensive, but don’t expect fanciful titanium creations to ever be cheap.

Design Challenge

The challenge for designers is to get as close as possible to the 8kg weight goal without seriously compromising the strength and rideability of the machine. Current leader is Dahon, whose Helios SL weighed a genuine 8.65kg (19lb) when we tried it in August 2004.The Helios SL is a delightful machine, but it has 20-inch wheels, so it makes quite a big folded package. It also comes with beautiful, but frail Rolf wheels, and no mudguards, so it’s not really a daily commuter machine.

The Brompton is a classic commuter bike, but it’s heavy. In A to B 1, we built a lightweight Brompton weighing 10.9kg. Considering that the Brompton weighed 12kg at the time, this was, with hindsight, quite a good result for a broadly conventional three- speed bike.The following year we were at it again, fitting a 1950s alloy shell to the hub (saving a whacking 120g), fewer, slimmer spokes, a carbon fibre seat pillar, Birdy suspension polymer and a few other bits, hauling the weight down to 10.4kg (22.9lb).

TA AXIX Light Bottom Bracket

Some lightweight parts are strikingly attractive in their own right.This is the TA AXIX Light bottom bracket

For the next few years, the bike clocked up several thousand miles. Most of the parts lasted well, the only weak spots being the aluminium rear roller securing bolts (they should have been titanium), and the carbon fibre seat pillar, which ate through two frame bushes and ended up dangerously worn itself. In the meantime, of course, the industry had been busy with its own weight reduction programme, and although some of the new stronger Brompton parts (such as the handlebars) were heavier, most were lighter…The company was gradually catching up.

In April 2005, Brompton launched the 9.7kg S2L-X and left our lightweight machine looking a bit sad. Could we do better using the S2L’s new technology – principally a two-speed derailleur hub and titanium frame parts?

A to B Bites Back

Eight years after putting together our original machine (the day of the Princess of Wales’ funeral, for those interested in historical minutia), we’ve built a new machine that’s both lighter and stronger.This isn’t a stripped-down special – our bike has mudguards and all the usual equipment you would expect to find on a Brompton S2L-X, but with the ‘traditional’ M-type Brompton handlebars, because that’s the way we like ‘em. This older design has a shorter stem, saving 60g, but a more complicated handlebar, adding 110g, giving a net weight increase of 50g. Drat and double drat.The taller handlebars also make it impossible to fit the S-type’s shorter Jagwire cables, adding another 50g, so before we’ve even started, our bike weighs 100g more than Brompton’s super-light model.

…the trick is to replace steel parts with titanium… or aluminium…

If our bike is effectively a standard machine, how is the weight taken off? The trick is to work methodically through the machine, replacing steel parts with lighter alternatives. For safety-related bits, this generally means titanium, which is as strong as steel, but about 40% lighter. Less critical things can be replaced with aluminium – 65% lighter than steel, cheaper than titanium (not much in these specialist areas), but weaker, so it needs to be treated with care. Cosmetic things can be made in plastic, or omitted altogether, but ‘easy’ weight savings of this kind will be hard to achieve if the development engineers have already done a good job.

Brompton Folding Bike Clamp

Tranz-X clamp - note the reversed nut and pin preventing the clamp from rotating

As in 1997, we’ve laid out a table indicating the cost-effectiveness of each change. Today, most of these lightweight parts are easily obtainable from Brompton dealers and other specialist outlets, so they’re cheaper than they were eight years ago. At anything up to £1 per gram saved, it’s still an expensive business, but to paraphrase the RSPCA, titanium is for life, and not just for Christmas. Once you’ve raided the piggy bank and fitted the bits, they can be transferred from bike to bike until your knees give out, and then passed down as family heirlooms.

If you’re in the market for the bigger, more expensive chunks of titanium, it’s generally cheaper to go for broke and buy one of Brompton’s own lightweight machines. As fitting is so complex, the two-speed derailleur probably comes into this category too. Even if you’re hoping to upgrade a near-new six-speed bike, it will be easier (and cheaper) to sell the old one and buy a new two-speed.

Top of the ‘worth doing’ list are things like pedals, handlebar grips and reflectors, lighter versions of which can be found quite cheaply.We chose to leave the wheel reflectors off altogether, but you may feel it’s not worth compromising safety for the sake of a few grams. Other parts, like alloy spoke nipples and lighter 14-gauge rear spokes, are cheap, but fitting can involve a great deal of labour, and the long-term strength of the bike will be slightly compromised.The S-type’s Stelvio Light tyres and tubes come into this category too – they are lighter, but more vulnerable to punctures.

Some standard parts are hard to beat – for example, there’s very little to choose between 3/32” chains.We spent £26 and saved a paltry 16g by fitting a KMC X9 Gold chain which is, believe it or not, gold plated. Still, it goes very nicely with the exposed brazes on the Raw Lacquer frame. It’s difficult to beat the weight of the standard Brompton saddle too. On our original bike, we fitted a Terry Race Vanadium saddle weighing 227g.We were able to reuse it, which is fortunate, because it no longer seems to be available.The best we could find today was the Fizik Vitesse Twintech ladies saddle, weighing a claimed 230g and costing £60.This sort of upgrade could never be cost-effective, but saddles are a personal thing, and in the final analysis, a lightweight bike is a fashion statement. Like any other fashion statement it wouldn’t be complete without a few decadent touches.

Superlight Brompton Folding Bike

Superlight Brompton Folding Bike Components

Anything we’ve missed? The cables and brakes could be lighter, but it’s unlikely the weight and complication would be worthwhile. Otherwise, apart from odd nuts and bolts, we’ll probably have to wait for Brompton to introduce a titanium mainframe, which would save perhaps another kilogram.

On the Road

If you’re worried about the lack of gears, don’t be. Under most conditions, the two-speed derailleur performs much like a conventional three-speed Brompton.The bottom gear of 56″ can tackle hills of up to 12.5% (1:8) with a suitably enthusiastic rider, and the top gear of 74″ is adequate for most urban situations. If you can live with a slightly high pedal cadence, it’s OK on the open road too.As we’ve suggested elsewhere, it may be possible to change the 16-tooth sprocket for a 17-tooth (a 53″ gear) without any other work, and with a bit of titanium-bashing, an 18-tooth can be squeezed in, giving a bottom gear of 50″.That’s almost as low as first on the old three-speed, but a bit of a jump down from top gear, so we’ve left the gearing unchanged and will see how we get on.

In theory, the lightweight parts make next to no difference in terms of speed, but the lighter rotating bits improve acceleration, and they certainly make the bike feel livelier and sharper to ride.We can only say that our lightweight bike seems to accelerate well, and it’s a delight to ride. If it feels good, that’s all that really matters…

Carrying the bike is obviously a lot easier. It’s difficult to visualise how light it is, but try taking the wheels off a Brompton L3 and lifting it…

What does the bike actually weigh? Er, um, a bit of a dispute here. All the parts, old and new, passed over our traditional scales, so we’re quite certain that our bike weighs 2.5kg less than a standard M3L, or L3 as it used to be called. But according to our electronic scales, the finished bike weighs 9.5kg, which is two or three hundred grams more than we were expecting. Drat and double drat!

And how much did it cost? This is another tricky question, because the costs depend on how you do it.To upgrade an elderly Brompton would cost around £800, excluding the two-speed kit, which is not really cost-effective as an upgrade. If buying a new Brompton, the cheapest option is to start with the M2L-X, which comes with most of the Brompton lightweight kit for £873. Adding the Stelvio tyres and the A to B bits and pieces would cost another £250 or so, and bring the weight down to 9.2kg or 9.5kg, depending whose scales you believe.


Not all these parts can be bought off the shelf. The locknut on the Tranz-x seatpost clamp has been turned down to fit inside the Brompton frame lug, with two pegs fitted at the other end to stop the clamp assembly rotating, effectively mimicking the action of the Brompton clamp.The Birdy yellow suspension polymer is a useful upgrade, especially for lighter riders, but needs some shaping to fit – ours is also drilled like an Emmenthal cheese to give a softer ride. We used an aluminium bolt in the suspension, but this should really be titanium.The axle on the AXIX titanium bottom bracket has marginally less bias towards the chainring than the Brompton’s FAG axle. We fitted a 1mm shim, but tolerances vary – we probably didn’t need to. Two home-engineered bits we didn’t reuse this time were the alloy three-speed cable-guide nut (not needed) and the steering head alloy expander nut, which is now a standard fitting.

Giant Revive Spirit Electric Semi-Recumbent

Giant Revive Spirit

Giant Revive Spirit Electric Semi-RecumbentThe Giant Revive, it’s fair to say, has been a long time coming.We first heard whispers of a commercially-produced semi-recumbent bicycle some years ago, and eventually saw one in the summer of 2002.The non-assisted versions went on sale the following spring, the electric variant finally arriving in the summer of 2005.

…if ever there was a candidate for electric-assist, the Revive is it…

If ever there was a candidate for electric-assist, the Revive is it – a dead-cool laid- back beastie, but heavy and relatively difficult to pedal, for all sorts of reasons. From Day One, the conventional model looked power-assisted, and now, with the UK launch of the Spirit derivative, it is.

The Revive

Giant Revive Spirit Electric BikeA brief recap. In recumbent terms, the Revive might be described as a short wheelbase semi-recumbent.The frame is alloy throughout, with various bits hung from a solid- looking main tube that drops down from the steering head area, giving a usefully low step-thru, then sweeps back and up over the rear wheel.The wheel is fixed to another frame member that pivots just ahead of the crank and is supported by a spring/damper unit under the seat tube, which swings sharply upwards from the main frame.Wheels are 406mm (20-inch).

The Revive is one of the tallest recumbents you’re ever likely to see, so don’t expect the drag co-efficient of a tarmac-scorching HPV racer. On the other hand, it’s dead easy to hop on and off, comfortable to ride, and the drag characteristics are about the same as a much less comfortable drop-handlebar upright, or ‘wedgie’ as the recumbent folk like to call them.The comfort and reasonable drag are excellent news.

Giant Revive Spirit Electric BikeLess satisfactory is the weight, the price and the slightly awkward pedalling position. In its short life, the Revive has been produced in a number of versions, but only two models are currently on sale in the UK both with hub gears – Nexus 7-speed on the Revive DX N7 (£675), and Nexus 8-speed on the more luxurious LXC N8 (£875). Giant is a bit coy about weight, but reports suggest these non-assisted machines weigh at least 19kg (42lb), which compares rather badly with similar conventional bikes.With low drag and high weight, bikes of this kind tend to see more extremes of speed than a traditional bicycle – heart- stopping descents and painfully slow climbs. And that’s where the power-assisted Spirit comes in, because a little assistance goes a long way to even out your progress.

Revive Spirit

Giant Revive Spirit Electric BikeAt £1,499, the Spirit is the most expensive electric bike in the UK, by several hundred pounds. It’s also the most sophisticated: lithium-ion battery, integral trip computer, automatic halogen light and many other cumfy luxuries. Strangely enough, given the quality of the equipment, the Spirit is fitted with one of the world’s most basic hub gears; Shimano’s three-speed Nexus.We express surprise because this hub is also available in Auto-D form, and an automatic hub would seem ideal for a laid- back flagship like the Spirit. And this year, Shimano has introduced something called Di2 cyber Nexus, bringing together its generally well considered eight-speed hub with a front hub-powered computer, auto shift mechanism, auto suspension, auto lights, and… well, you get the idea.

…an auto hub would seem ideal for a laid-back flagship like the Spirit…

In the end, one assumes, Giant had to stop specifying equipment, to bring the Spirit in at a just manageable price.Weight must have been a problem too. Semi-recumbents with bodywork look oh so cute on the CAD screen, but every panel and bit of trim adds a few grams, and on a bicycle, weight is a real killer.To be fair, given the weight of the non- assisted versions, the Spirit does rather well at 33.2kg complete with battery.

In electric bike terms, that’s well below the average weight, but a few kilograms heavier than the Ezee Sprint, and a lot heavier than Giant’s own featherweight Twist models, which start at 22.2kg. Incidentally, if you’re one of those people who look at things in purely practical terms, the Spirit is completely outclassed by the Twist. Against the basic Twist Lite, it costs 67% more, weighs 50% more and offers 17% less range. Clearly, if it doesn’t triumph in some other department, it’s doomed.

What the naked facts and figures don’t convey is style, something the Spirit exudes from most of its pores. Put it this way, it’s the only bike that drew a crowd just to see the box opened. Giant took a gamble introducing a recumbent, but they got the design broadly right.The styling looks flash enough to tempt snazzy Kings Road types, while the soft greys and blues of the colour scheme will appeal to doddery greys promenading the Costa del Sol.This really is the bike for everyman and everywoman, provided, of course, they have fifteen hundred quid burning a hole in their pocket.

On the Road

Giant Revive Spirit Electric Bike

These panniers are small, but there’s plenty of room for full size ones

By and large, the Panasonic power unit fits quite neatly into the Spirit.The motor/gearbox sits where the bottom bracket would be, in the suspended part of the frame, and the tiny li-ion battery is secreted away in a streamlined box behind the seatpost and under the rack. The high rack gives plenty of room for full- size panniers or indeed – with the addition of a couple of footpegs – a small person. Giant’s lawyers have gone mad on this one, ruling out any sort of child seat on pain of death. That’s a shame, because it’s a roomy, sprung platform that could be very effective for dropping little Tarquin off at school. Giant  suggests a maximum load of 15kg, but the rack is a rugged affair, so we’d guess that a touring load of twice that amount would be secure. Usefully, the rack is within easy reach, so mobile phone, camera or binoculars are just where you want them. Less usefully, the rack bars are too wide for standard pannier clips.

With no fewer than five height/reach adjusters, the Revive will fit almost anyone. Giant claims a range from 5′ to 6′ 5″ tall, something that we can more or less confirm. The saddle slides along a steeply inclined stem like any other bike, but in this case there’s also a lumbar support that should nestle comfortably in the small of the back and a saddle fore/aft adjuster.This – to put it in the crudest possible terms – is a bottom-sizing gauge. Pert, compact bottoms will be more comfortable with the saddle back, whilst wobbly couch-bums will prefer the saddle forward.

Having wiggled your nether regions into position, the next task is to move the handlebar stem back and forth and up and down to find a comfortable position. Both operations are controlled with one clever quick-release, and fine tuning doesn’t seem to be as critical as it would be on a conventional bike. In practice, adjustment of the saddle and handlebars isn’t usually necessary, with most people under six foot sharing the same settings. Even where adjustments are needed, they’re quick and easy to make. From this point of view, the Revive is a practical multi-user machine.

Giant Revive Spirit Electric Bike

Saddle fore and aft adjuster on the left and height adjuster on the tends to make the right.The saddle runs in the two inclined tracks. suspension bob up

Once you’re comfortable, it’s time to fiddle with the suspension spring pre-load and damper rate.The damper knob is easy, but unlike the cheaper DX, the knurled spring adjuster ring is rather tucked away on the Spirit, making this operation a bit difficult. On our bike, the pre- load was set right at the wobbly couch-bum end of the range, so we had to do some fiddling to get enough suspension movement.

On a conventional bike, pedal force platform.The battery lives under here and down, but this with a semi- recumbent, especially a power-assisted one, so the spring and damper can be set softer than normal, giving a real ‘magic carpet’ ride. ‘This’, said one very occasional bicycle rider, ‘doesn’t feel like a bicycle at all!’ That sort of comment will bring smiles and nods of approval in the Giant boardroom.

Giant Revive Spirit Electric Bike

Saddle, lumbar support is less of a problem and rear rack

Rather surprisingly, the Revive has no suspension at the front, so the front tyre pressure needs to be kept quite low.We chose the maximum of 55psi at the rear, but only 20psi in the lightly-loaded front tyre.That’s acceptable, provided you bear in mind that a recumbent cannot be ‘lifted’ over bumps like a conventional bike, so kerbs must be tackled with some caution.

Handling is relaxed and unspectacular.At low speed, the bike goes more or less where you point it, but on a fast bend, it usually needs some sort of corrective flick halfway round. No real problem, but adding a little excitement to an otherwise uneventful ride. Without power, the lack of gear range is all too obvious.The Nexus hub gives a bottom ratio of 45”, middle of 61” and top of 83” – spot-on for power-assist, but a bit high for a heavy bike on muscle-power alone.That said, the Spirit trogs along quite well in flattish terrain, provided you don’t mind being overtaken by old ladies on rusty shoppers.

Giant Revive Spirit Electric Bike

The suspension is enclosed. Note the damper adjuster knob

Power is brought in by pressing a big red button, which unleashes a high-tec bleeping noise and some rather ineffectual power-on-demand when the pedals are turned. At low speed, the motor is surprisingly noisy, making the sort of whining noise that Foden lorries used to emit on gradients.That might be a bit unfair, but it’s certainly noisier than the Twist: a background whine, with overtones of Tardis. Grumbling and whining thus, the Spirit accelerates painfully to 12mph before running out of steam (although oddly enough, the motor continues to run quietly in the background right up to 15mph, but without doing any useful work). If that was the end of the story, Giant would be in big trouble, but the Spirit also has a twistgrip and a lock-button labelled ‘cruise’.

It took us a while to get the hang of all this. Basically, the default setting is what you might call ‘economy’ mode (‘Pedal Activated Power’ in Giant-speak), and the twistgrip can be used to dial in a bit more oomph (‘Variable Power Control’). For long boring ascents, the level of assistance can also be locked with the ‘cruise’ button, keeping output at the chosen level until you brake or stop pedalling.

This all sounds a bit complicated, but it works. If you’re just cruisin’, switch on and pedal gently away at up to 12mph. If you’re late for work, lock the twistgrip on full and you’ll spurt off.Well, perhaps ‘spurt’ is a bit strong.We didn’t dare dismember the power unit to get the figures, but the Li-ion unit is definitely less powerful than the older NiMh device fitted to the Twist. On the flat, speed rises at a reasonable rate to the legal limit of 15mph, at which point the motor cuts out rather abruptly. If your poor legs can’t keep up, speed falls until the power pops abruptly back on, continuing to ‘hunt’ in and out of engagement for as long as speed stays in the 15-16mph zone.

The reason for this rather crude behaviour is that the Spirit is designed for the US market where (in most states) power is allowed to top-out at 18mph. For Europe, and other 24km/hr markets, the top speed is capped using the speedometer sensor on the back wheel. So if you’re very very late for work, you can swing the speedo magnet aside, disabling the speed limiter. Riding an electric bike at 18mph is a bit naughty, but a mere piffle against driving a ton of motor car at 50mph in a 30mph limit whilst blahing into a mobile phone and lighting a cigarette. Quite common in these parts.

In any event, the Spirit will only keep up 18mph under the most favourable conditions.The Giant Twist Lite will stomp up quite steep hills, but the reduced human and electrical input on the Spirit make it wilt very quickly.The basic PAP power setting allows you to struggle up gradients of perhaps 10% (1:10), but you’ll need to use all the gears, and it’s a slow process.Wind the twistgrip fully open, and the motor is zesty enough to tackle 12.5% (1:8) with reasonable ease, and climb 17% (1:6) with a fair bit of effort and some odd clonks and groans (not all of them from the rider). If you try rushing the gear changes, the Nexus hub adds some odd noises of its own, but we found the change improved with use.

Clearly, anyone expecting to sprint across the Lake District with a full touring load will be disappointed. A crank-motor of this type can be adapted for hill-climbing by fitting a larger rear sprocket, but this obviously lowers all the gears. A better solution would be to fit more gears, such as the 8-speed Di2 Cyber Nexus, or whatever Shimano calls it. Our advice is to test the Spirit on a familiar hill, if you can find a willing dealer.


Giant Revive Spirit Electric BikeRange on full power is so- so.There are three capacity lights: On our ‘mountain course’, the first popped off at four miles and the second at six miles, which almost caused us to abort the test. In practice, the gauge is a bit hit- and-miss, because we soon had two lights on again. Four miles on we were back with one, at 14 miles it began to flash, and the end came abruptly at 16.2 miles. Average speed was 13.7mph – quite low by modern electric bike standards, particularly considering the rapid descents. In flat country, we managed 17.4 miles at 14mph, which is even more disappointing.

By comparison, a Giant Twist will deliver about 20 miles from a battery of similar capacity.That said, the NiCd battery on the Twist weighs 3.9kg, and the Li-ion battery on the Spirit weighs only 2.1kg, so if you can afford £350, a spare battery will double the range without adding noticeably to the weight of the bike. Incidentally, the standard battery has a 144Wh capacity, but Panasonic also produce a tiny 86Wh unit and has just introduced a bigger version of 173Wh. If these fit the Spirit – and no one can tell us if they do – they would add greatly to its flexibility.

There’s more good news if you have the will power to leave the twistgrip alone, because this increases the range a good deal. After completing our full power run, we gave the battery a brief 2-hour charge (about 60%) and set off for home, covering the same 16 miles fairly easily with careful power management. Interestingly, average speed was not much less, at 12.5mph. It’s a bit difficult to put a figure on maximum range under gentler conditions, because so many variables are involved, but our experience suggests 25 miles or so.

…none of the arm, finger, neck and bottom aches that bicycling sometimes inflict…

One thing we can say is that the Spirit is at its best on long rides in rolling open country. In town, the gears crash and the motor whines and grumbles, but once up to 15mph (or 18mph) the power unit becomes less obtrusive and the bike proves surprisingly comfortable. After an hour and a half in the saddle, we experienced none of the arm, finger, neck and bottom aches that bicycling sometimes inflicts.The only slightly negative aspect is that the large saddle and backrest can get a bit sweaty after a while. Still, you can’t have everything.There was general agreement that long-distance comfort was the Spirit’s strongest card.

Almost without exception, riders praised the comfort, the visibility, the security of the low step-thru and the gentle assistance that dealt very well with nagging headwinds and rolling hills.

Charger and Accessories

Sliding the battery out looks easy enough, but it’s a two-handed job – one hand to turn the key and the other to pull the battery handle. If it’s tight, as ours was, it’s liable to free rather explosively, trapping your fingers painfully behind the rack tubes. If they’re all the same, this is a serious design fault, because most people would be unable to charge the battery without help.

The compact charger looks similar to the NiMH device sold with early Twist models, but it has no warning lights, the state of charge being determined by a row of LEDs on the battery. Like all Li-ion chargers, the Spirit charger is a complex animal, the technology being necessary to prevent the cells getting out of ‘sync’ with each other. Giant claims a charge time of four hours, but this proved slightly pessimistic.The primary charge takes about three hours and 20 minutes, plus another 20 minutes or so for the last few dregs. Not quite as rapid as filling a petrol tank, but in the electric bike world, three hours for a 95% charge is pretty good.

Based on the power consumed from the mains supply, fuel consumption is around 12.5Wh/mile, which is a bit on the high side, particularly for such a modest average speed. If we can believe the quoted battery capacity of 144Wh, we get a figure of 8.7Wh, which sounds much more impressive.With the bicycle costing £1,499, and replacement batteries at £350 a pop, it is hardly surprising that running costs are the highest we’ve seen. Our estimate is 11.2p per mile, or about twice as expensive as the cheapest machines.

Most of the accessories have been touched on elsewhere.We were impressed by the integral speedometer/computer in the ‘instrument nacelle’. Unfortunately, thanks to the threat of weather and vandalism, this is removable, and we had a few problems with the quick-release catch, which is hard to operate and liable to fail on the road.The computer never quite fell out, but once loose it stops working, which can be annoying.

Lighting is excellent.The Spanninga Ultra Xs rear light is a dynamo standlight version of the Ultra Xba fitted to the Twist Comfort – bright and very effective.The Spanninga Radius Auto headlight is a bit less successful. Like the B&M Oval lamp fitted to the Twist Comfort, this is an automatic system, feeding the front and rear light with power when it senses low light levels. But in this case, all three options – off, on and auto – are on one switch, out of reach on the headlamp. It’s fiddly to use, and finding the ‘auto’ setting can mean a lot of frustrating wheel spinning and head scratching. After a week or so, the rubber cap popped off the switch, which could have allowed rain straight into the electronics – a recipe for disaster. Once you get it working, automatic is excellent, turning on the powerful lights under trees or bridges, and even during gloomy weather.

Brakes are the reliable, but rather stodgy Nexus roller hubs.When new, these are weak, spongy and lacking in feel, but they do eventually run-in to give reasonable performance. Roller brakes can overheat on long descents, but they’re unaffected by water or oil contamination and require very little maintenance.


…the comfort and relaxed riding style will find many converts…

We’d hate to leave the impression that the Spirit offers more problems than advantages.That might seem true on paper, but for all its flaws, it generates a feel good factor that’s difficult to quantify – let’s just say it left everyone smiling. Unusually in our experience, even the most sceptical were won over, and everyone loved riding it.The Spirit isn’t very fast, but it can be a lot of fun on twisty descents, and on the long climb back up again, which is more than you can say for the unassisted versions.This sort of machine isn’t ideal for city commuting, but it strikes a good compromise: high enough to be safe in traffic, but low enough and long- legged enough to tackle a round daily commute of 15-20 miles or so, provided the hills aren’t too taxing. In practice, most purchasers will be older leisure riders, and for this market, the comfort and relaxed riding style will find many converts. Is it worth £1,500? Not in our book, perhaps, but if you’re finding a conventional bike hard work, it almost certainly is. Overall – rather to our surprise – we like it.


Giant Revive Spirit £1,499 .Weight Bike 31.1kg Battery 2.1kg Total 33.2kg (73lb) . Gearing Nexus 3-spd hub . Ratios 45″ 61″ 83″ . Battery Lithium-ion . Capacity144Wh . Spare battery £350 . Range 16.2 miles . Full charge 3hr 40m . Fuel consumption Overall 12.5Wh/mile Running costs 11.2p/mile . Manufacturer Giant BicyclesUK distributor Giant UK Ltd tel 0115 977 5900 mail info@giant-uk.demon.co.uk

DIY Traffic Calming

DIY Traffic CalmingOnce upon a time, not so very long ago,if you lived beside a British trunk road your life would be a nightmare of congestion, pollution and constant danger. As the years passed, the nightmare spread; first to ‘A’ class roads, then ‘B’ roads (remember when you could cycle on those sweeping rural highways?), and finally to unclassified roads in all but the most remote corners of these islands.

Today, almost every stretch of tarmac that isn’t protected by cameras, chicanes and speed bumps of various kinds has become a lethal rat run.West Park, Castle Cary is a good example – a cul-de-sac for God’s sake, but somehow traffic manages to thunder up the road at 30mph before screeching into one of the rare parking spaces. If they’re all taken, the vehicle simply double parks.

The Problem

The problem is that we walk and cycle along our road, our pets do whatever it is that pets do along it, and our children play, and learn to ride bicycles here too. If children cannot safely learn to ride on a suburban cul-de-sac, where can they learn? And if we give in and accept that all roads are now too dangerous, is there really any point in them learning to ride at all?

…visual clues indicate… that this road space… is where people live, walk, talk and play…

Our road and the houses along it  were once owned by the local authority, until such social housing was swept away by Mrs T’s home ownership revolution.The handful of houses remaining in local authority hands were transferred to a housing trust, which also took control of the car park, while the rest of the road remained with the authority.

We asked the trust if speed humps or warning signs could be put in, and although generally sympathetic, it said this was really a local authority problem, suggesting we petition the Highways Department at the local district council.The reply, a full month later, is perhaps indicative of the thinking prevalent in those authorities where the 1960s car revolution is still very much underway. Naturally, the traffic engineer shared our concerns, but was at pains to point out that:‘…children should not be playing in the road. It is a dangerous practice and should be discouraged.’ Remember, we are talking about a short cul-de-sac ending in a car park used primarily by residents.The highways man continues:

‘There are warning signs that we can erect, but the guidelines we have to follow clearly state that they should only be used to warn drivers of the presence of schools or playgrounds and the likelihood of encountering children on the road ahead.This does not apply as far as West Park is concerned… if we were to erect a sign and there was an accident, it could well put the Highway Authority in a vulnerable position…’

School Crossing Road SignNot to put too fine a point on it, this is utter nonsense. According to the Department for Transport’s ‘Road Safety Good Practice Guide’, urban residential roads account for nearly 40% of all crashes (‘accidents’, according to DfT) and a high proportion of the casualties are children.The answer, according to recommendation 4.67, is that: ‘On residential access roads drivers need to be given visual cues that indicate strongly that this road space is part of the environment where people live, walk, talk and play.’

Traffic calming measures can be quite problematical. Speed humps are complex to install, the emergency services may choose to object (less likely on a cul- de-sac, of course), and to be safe and fully effective, they must be well lit and signed. Surely the answer is a warning sign, indicating that children might be playing? Something that children have always done and always will do, on quiet cul-de-sacs?

In practice, there’s nothing to stop you buying a road sign and erecting it on private land, but there is very little precedent for members of the public purchasing DfT-approved signs and erecting them in a public place. In our case, the sign would need to be fixed to a local authority pole, on the boundary between the road owned and managed by the local authority, and the car park owned and managed by the housing association.

…anyone responsible for a hazard is entitled to warn road users about it…

Local authorities have wide powers to remove unauthorised advertising signs, and equally wide powers to put up their own road signs, provided they are produced to exacting standards laid down by the Department for Transport in the guidance notes ‘Traffic Signs Regulations and General Directions’.Where motorists are likely to encounter children, the appropriate sign is one that will be recognised by all road users – these are commonly found on the approaches to schools and playgrounds, but not, as our local authority claims, exclusively in these places.The particular hazard is usually indicated beneath the sign, and there are several options available, most appropriately in our case, the all encompassing:‘Caution Children’.

Anarchy in the UK?

If members of the public started putting up ‘obligatory’ road signs wherever they wished, traffic management would deteriorate into a state of anarchy, but the rules regulating triangular warning signs are rather different. If your car breaks down, you’re entitled to display a warning triangle, and in practice, anyone responsible for a hazard is entitled – even encouraged – to warn road users with appropriate signing.We had informed our local authority of a hazard (namely Alexander and co) and the authority had shown itself unwilling to help, so we decided to go it alone.

Several companies manufacture road signs, either to customer specifications for private roads, or to DfT specification for highway use.We chose to buy from HM Prison Coldingley, near Woking in Surrey. Coldingley is one of the key manufacturers of DfT- approved road signs, and can supply anything to order, profits helping to run the prison and giving a small income to prisoners.These things aren’t cheap, but they’re well made and obviously designed to survive in all weathers for many years. Our sign, in the smallest standard size (575mm x 870mm, including the warning plate) cost £105, complete with fitting kit and delivery.

One thing we weren’t expecting was the goodwill of friends and neighbours telling us just how much they appreciated the sign, and it does look businesslike. Does it work? All the indications are that it works very well indeed. In the short-term at least, traffic speeds are reduced, and cars are approaching with a new awareness that – as the DfT puts it – they are entering road space where people live, walk, talk and play. Motorists are not demons, they’re ordinary folk, but a lack of guidance from above had allowed our tiny road to become a race-track by default.With an appropriate message, drivers have once again started to drive in an appropriate manner. It really is that simple.

Home Zones

Home Zones are a successful feature of the road scene in The Netherlands, and a few pilot schemes have been established in the UK. Home Zones are usually established in urban residential areas, using street furniture, vegetation and other features to break up the street, and make motorised road users feel less comfortable, reducing the speed and volume of traffic. In rural areas, roads may similarly be designated as Quiet Lanes, the aim being to encourage pedestrians, cyclists, horse riders and wildlife to return. As our experience shows, not all highways departments and traffic engineers are enthusiastic, but under the Transport Act 2000, they certainly have the power to designate any road that meets DfT criteria as either a Quiet Lane or a Home Zone. Broadly speaking, a rural road is considered suitable if it carries less than 1,000 vehicles per day, and a residential road if it carries less than 100 cars ‘in the afternoon peak hour, with little or no through traffic’. Get counting and good luck! You have nothing to lose and everything to gain!

Further reading: The DfT website includes a great deal of information on road safety, road signs and Home Zones. The l can supply books, leaflets, videos and advice on all aspects of Home Zones and other street-calming initiatives: www.ncb.org.uk, Play England. HM Prison Coldingley tel 01483 804300 fax 01483 804427

Ford Synus

A to B 49 Blog, August 2005 – SRA, ABD, Merc

Strategic Rail Authority, Association of British Drivers, Merc folding bike

Good news from Bogworthy Junction! The much derided Strategic Rail Authority has finally been abolished, but not before dropping, as a parting bombshell, that services to Bogworthy will be downgraded in the new Greater Western Franchise. But at least we have seen the back of an organisation that was neither Rail-friendly nor Strategically-minded.The bad news is that most of the staff are expected to transfer to the Department for (Road) Transport and continue mishandling rail matters from there. Still, one assumes that the forces of the state know what is good for us.

Most trains these days have space for only two to four ‘cumbersome’ machines, and long-distance travellers are generally obliged to book ahead. Once upon a time, this was done by speaking to a humble, but knowledgeable, railway clerk, who would transfer the information to another similar bod in the bowels of railway HQ, who presumably signed a chit or stuck a Post-it note on a giant map of the network. However it was done, the system worked reasonably well until January 2005, when modernisation resulted in the new, and fearsomely powerful, National Reservation System, costing a staggering £80 million. Booking has since become a hit-and-miss affair, particularly when crossing network boundaries with a bicycle.

To provide just one example, the little train for Kyle of Lochalsh, which carries two bicycles, recently pulled in to Inverness, where no fewer than ten cyclists were waiting, reservations in hand. Eight of the ten weary cyclists travelling that day had already been crammed into six bicycle spaces on another train.


Merc Folding Bike

Regular cycle/rail commuters are buying folding bikes in droves, and who can blame them? But these days, folding bikes might not be all they appear to be either. The Chinese have developed some serviceable nuclear weapons, and shot all manner of dangerous things into space, but the finer points of folding bike technology continue to elude them. The latest arrival from the east is the Merc, a straight copy of the Brompton. This sounds great news for consumers, being made of aluminium and very pretty to look at, but the reality is something of a disappointment. As one understands it, aluminium is lighter than steel, but for reasons that only the boffins are able to explain, the aluminium Merc weighs a hefty 13.2kg, and is thus significantly heavier than the steel Brompton. The Mole took the opportunity to ride one of these faux-Bromptons at the CTC York Rally and found all sorts of oddities in the handling, brakes and folding. A bit of a dodgy purchase at £499 then, but is the company really allowed to sell such blatant copies? As with so much in and beyond the Euro-zone, the answer appears to be yes and no. Merc bikes have been seized and impounded on the European mainland, where copyright laws are interpreted in a relatively protectionist manner, but not in Britain, which adopts a more laissez-faire approach.

Surely the Merc is a straight copy, passed off as a Brompton, bringing only some rather heavy aluminium to the party? Even the Merc instructions are copied from the Brompton handbook. And if the frame is wobbly and the brakes dangerously weak, surely the bike must fall foul of British Standards too? It seems not, or at least Trading Standards has made no move to prevent the open sale of the machines.

atob-blog-mark-mcarthur-christie-mercThe road lobby isn’t all it might appear either! Road interests are advanced by something called the Association of British Drivers, a hang ’em, flog ’em and run ‘em down operation, composed largely of middle-aged men of the kind that wear trilby hats and grip the wheel with chamois leather driving gloves. Believing in broad terms that motoring should be fast, cheap and convenient, the ABD lobbies hard against speed cameras, taxation and road pricing, as one might expect. But Mark McArthur-Christie, the ABD’s Road Safety spokesman appears, to have gone native! After riding a Dawes Galaxy to work and rather enjoying the experience, Mark ‘didn’t bother’ replacing his car when it was written off, and is now car-free. ‘If I absolutely need a car, I hire it’, says the ABD man. For National Bike Week in June, he went a step further, organising a car, bike and bus Oxford commuter challenge.

It’s an odd world: Strategic Authorities that offer no strategies, Bromptons that are not Bromptons and now car lobbyists without cars. While the bearded, sandal-wearing anti-road types arrive at demos by car, the bicycle in the bushes could well belong to the ABD man behind the bulldozers, or perhaps even the chairman of Shell (see previous issues), should he happen to be passing. In the era of Peak Oil, one would be well advised not to jump to any conclusions.

So where is personal transport heading? Celebrities are flocking to folding bikes as never before: in the old days, if you pulled up beside a vaguely familiar face on a Brompton it was almost certain to be Adam Hart-Davis or Simon Calder.These days, it might be all-purpose celeb Jerry Hall, former boxer Chris Eubank, Member for Bath Don Foster, or Tory something-or-other Bernard Jenkin MP. The latest convert is television presenter Kevin McCloud, who felt sufficiently strongly to order Bromptons for himself and two other directors of his production company.

Incidentally, Strida enthusiasts include film maker Spike Jones, Radio 4 presenter Libby Purves, racing champion Stirling Moss, and the Queen’s nephew Lord Linley.


At the more vulgar end of the transport scale, it seems Hummer owners are enthusiastically signing up for the new SYNus, which sounds like a nasal problem, but is actually an ‘urban command centre’. According to manufacturer Ford the SYNus is a ‘mobile techno sanctuary sculpted in urban armour and inspired by the popular B-cars of congested international hotspots’. In practice, this means it’s a security truck, complete with steel shutters that rise up to shield the windows, and deadlocks to disable the doors. Lock your keys inside and you might as well start saving up for another one. Lock your dog inside on a fine summer’s afternoon and the poor chap will be done to a crisp by the time they cut him out.

…such everyday accessories as bullet-proofing, a mini safe and infrared night-sight…


But as one rather suspected, the SYNus is a mere runabout. Meet the $225,000 Bad Boy Heavy Muscle Truck, a post-apocalyptic urban nightmare, based like the Hummer, on US military hardware, but in this case on the rather larger Medium Tactical Vehicle. The Bad Boy weighs six tons, stands ten feet tall and can be ordered with such everyday commuter accessories as bullet-proofing, a mini safe and infrared night-sight. The $750,000 ‘NBC’ version offers protection from ‘dirty’ nuclear bombs and biological agents. Fuel consumption is a little under 8mpg, which sounds rather good, all things considered. The Mole is waiting for the civilian version of the Chieftain tank.

Hybrid Motor Gearing

Electric Bike Hybrid Transmission

Professor PivotThe time-honoured bicycle drive system of pedal cranks, chain drive, and hub or derailleur gears has been in vogue for more than a century, and shows no sign of going away in the immediate future. But new thinking is starting to make an impact, and I am indebted to engineer Frank Moeller for his thoughts on the future of bicycle transmissions.


Frank’s inspiration came initially from a desire to produce a more efficient electric-assist bicycle. Electric bicycle motors can be more than 80% efficient, but a bicycle is a demanding environment, and motors generally work efficiently over a limited speed range.To keep the motor spinning close to this ideal speed, it needs to be near the pedals, as on the Panasonic drive system fitted to the Giant Twist.

This arrangement ties the motor speed to a comfortable pedal cadence, cleverly utilising the human engine to select a comfortable gear for both leg muscles and electric motor. Generally this works well, but the motor speed still varies a good deal, and with transmission losses, overall efficiency probably doesn’t exceed 60% in most cases. In other words, a typical power-assisted bicycle carries around a heavy, expensive battery, yet turns 40% of its capacity into worthless heat.That’s a better performance than most internal combustion engines, but on a bicycle – where weight is a serious issue – this poor performance is inexcusable.

Most electric vehicles throw power away on descents too.The motor could run as a generator, putting power back into the battery, but with most older designs, the noise and friction involved generally outweigh the potential benefit of recycling a little of the energy. How can matters be improved? it seems a number of avenues are worth exploring.

New Technology

Without going into too much technical detail, large ‘switched reluctance’ and ‘induction’ motors are already available, and they’re much more efficient than older types. Combine the best of these designs and there’s no reason why a new smaller ‘hybrid’ couldn’t be produced – light enough and efficient enough to fit inside a conventional bicycle hub, turning quietly and with little friction whenever the wheel turns. Such a motor would give assistance up hill and braking down hill. None of these new motor designs have yet been optimised for light electric vehicles, but engineers are working on the problems.

Today, motors and gears are usually so crude and noisy that the system necessarily spends much of it time disconnected.The new hybrid motor would be fitted inside the front hub, driven at speeds of 3,000rpm or more through a single-stage stepped epicyclic ear.This permanently engaged motor would run reasonably efficiently across a broad speed range and provide both assistance and braking.

It’s a neat idea, but Frank Moeller’s key conceptual breakthrough is to take this arrangement a step further and design a completely new bicycle drive system, based broadly on the transmission of the ‘hybrid’ petrol/electric Toyota Prius, but in this case combining and regulating human and electric power inputs.

Toyota Prius

The Prius has won many awards since its launch in 1997, and it’s easy to see why.This outwardly conventional car draws power from a small and relatively efficient petrol motor linked to the planetary gears of an epicyclic gearbox.

Hybrid Motor Chart

This is the same compact, efficient device used in hub gears, but in this case its purpose is to split the motor torque into two streams; one leaving through the sun gear to turn an electrical generator, and the rest going via the outer ring gear to the car’s wheels. On some designs the shaft to the wheels can pick up extra torque from an electric motor, but on others the motor is mounted at the other end of the vehicle to give four-wheel-drive.

This ‘Hybrid Synergy Drive’ might sound complicated, but it does away with the conventional clutch and gearbox, and performs most of the braking functions, because the clever ‘torque splitting’ arrangement functions as a continuously variable transmission. At low speed the petrol engine is turned off, and power is drawn from the batteries, via the electric motor. As the vehicle accelerates, the petrol engine is started, feeding power to the epicyclic. At first, the output shaft and wheels are turning slowly, so most of the power is diverted via the generator and converted to electrical power to feed the motor. This might be described as ‘first gear’. As speed rises, the ‘braking’ effect of the generator is progressively increased by electronic means, transferring more and more of the available torque directly to the wheels, with a smaller percentage being turned into electrical power by the generator. Above a certain road speed, the generator is given a high electrical resistance and the unit is effectively in ‘top gear’ As driver input and road conditions vary, the amount of power flowing from the generator to the motor is continuously adjusted, keeping the petrol engine turning at an optimum speed under almost all conditions.

Hybrid Motor Hub

Patent diagram

Hybrid Motor Gearing

Bench test rig In both cases, input power is spilt into mechanical and electrical components, which are recombined in the output stage

For hard acceleration, extra power is supplied from the batteries, which will be recharged from the motor/generator when the going gets a little easier, or under braking. Back in low-speed stop-start urban driving conditions, the inefficient petrol engine is turned off, and the battery/electric motor combination takes over again. The torque split allows this clever transmission to make the best use of the very different characteristics of the electric motor and petrol engine, and it can be arranged to do the same with an electric motor and human ‘engine’. Ignoring the on-board battery for he time being, rider effort would be applied to the pedals as normal, and conveyed to the rear hub via a chain drive.

…the hub actually contains fewer parts than a typical five-speed hub…

In the hub, some of the human input would proceed direct to the wheel, with a proportion being diverted via a generator/motor electrical circuit, as on the Prius, but in this case the low pedal speed is geared up to give a high generator speed.When climbing a hill, the wheel would begin to slow, causing an increasing amount of torque to run via the generator.The electrical output from the generator would run just a few centimetres to an electric motor/generator, with the mechanical output being fed to the hub shell through a second epicyclic gearbox.

It might look complicated, but the hub actually contains fewer parts (and far fewer wearing parts) than a typical five-speed hub, and it’s fully automatic. And of course the system really lends itself to electric-assist, requiring just a battery and a few control circuits to turn the human-powered vehicle into a hybrid. As on the Prius, the battery would provide additional power for acceleration and hill-climbing, and absorb ‘waste’ power when coasting downhill. It would also be possible to recharge the batteries with pedal effort under favourable conditions.The major difference is that in stop-start town traffic, where the Prius petrol motor would be turned off, the primary input would be from the human ‘engine’ rather than the battery.

A New Era

A ‘torque split’ transmission would provide an HPV or assisted-HPV with a number of hitherto unattainable attributes. For the human ‘motor’, the hub gives a foolproof continuously variable transmission, with no gears to worry about.The hub could be set to provide either a constant input torque, constant pedal cadence, or a combination of the two, maintaining this optimum level under all conditions.The rider would simply point the bike in the right direction and start turning the pedals.Without the shock-loads imposed by frequent gear changes, maintenance would be reduced, and it might be possible to reduce the size and weight of components such as the crank and chain. And with the output motor able to function as a generator, recycling some of the power normally turned to heat by the brakes, the bicycle could be fitted with a small battery, or even a ‘super capacitor’ to store braking energy.This reduces the need for powerful brakes, reducing the size and weight of the braking system too.

Although bristling with technology, the hub would be simple, and easily fitted to a conventional bicycle.The one unit would replace the conventional gears, and reduce the weight and complexity of the transmission and brakes. On an electric bike, it would also replace the electric motor, wiring and control equipment.

Fact or Fantasy?

How close is this vision to fruition? In motor car terms, the engineering is quite simple, but scaling the technology down will present many challenges. Prius consumers were initially nervous about the reliability of the novel electrical components and especially the batteries, but Toyota had sufficient confidence to offer a 100,000-mile warranty on the hybrid drive, which has proved extremely reliable.The same rugged simplicity and fully enclosed transmission would suit a bicycle very well. Moeller is already working with business partners in Taiwan, with the intention of mass producing hub units for just a few hundred dollars, to be fitted to new bicycles or sold as after-market accessories.The future may arrive sooner than you think.

Our grateful thanks to Frank Moeller. For further information, Frank can be contacted at frank.moeller@ntlworld.com

A to B 49 – Aug 2005


Bobike Junior Child Seat

Bobike Junior Child SeatMost of our friends were agreed on one thing when Alexander arrived – we might previously have lived a car-free lifestyle as rootless ‘dinkies’, but all that was going to change. Sage nods all round.

First there would be nursery, followed by playschool (both made worse when we exercised our parental prerogative and chose out-of-town groups), then school, plus a long list of extracurricular activities and a ceaseless round of parties in distant villages. Some of them even began discussing car-share schemes.

The car never happened, and we’re glad of that, because not having access to a car doesn’t half concentrate the mind when choosing transport options. Child trailers saw us through those infant years – pulled initially by one or the other of our Bromptons, but later behind the priceless Giant Lafree power-assisted bike, especially as the boy grew, and the volume of ‘stuff’ expanded (parents will understand).

For train-assisted journeys, we used a range of folding/collapsible solutions, graduating from a baby sling to a Burley Solo child trailer, a Brompton-mounted child seat, and most recently, the invaluable ITChair. For the school run – and optional for longer journeys – the mainstay has been Steve Parry’s tandem Brompton.

Older Children

With the boy now six-and-a-bit, and sprouting like a bean up a pole, the on-bike options are becoming more limited. But if someone tells you their child went solo at 31/2 and now pedals him/herself everywhere, they’re either living in the Outer Hebrides, lying, mad, or (more likely) using a car for the tricky bits. Alexander often rides his own bike to school and to local parties, but when he’s tired, or the weather’s dubious, or we’re riding a long way, it still makes sense to travel en tandem: For years, we’ve used a rack-mounted child seat on the Ezee Sprint electric bike, but the rack was starting to sag. Clearly, we needed something sturdier.

Years ago, before the invention of the bulbous people-mover, bicycle seats for older children were quite common, but they’re much rarer these days. Any number of manufacturers produce rack or frame-mounted seats, but very few of these are suited to children of five and above.

Bobike Junior Child Seat Folded

Folded down, the Junior is unobtrusive, but the harness straps must be secured with care


The bag bracket will carry a pair of small panniers either side of the seat, or a lightly- loaded rucksack when folded down

In Holland and Germany, as we so often point out, it’s another world, and child- carriers abound. One of the very few to have found its way to Britain is the Bobike Junior, a rear-mounted seat designed for children from four to nine years old (or five to ten, depending which brochure you’re reading). If you have a podgy 91/2 year old, we should qualify that upper age limit, because in the small-print, the gross weight limit, including luggage, is 32kg, or five stone in what Francois Mitterrand would call Anglo-Saxon measures. For reasons that will be explained, we wouldn’t recommend exceeding this limit.

Fittingly, in this ‘vision of the future’ issue, the Bobike Junior is a clever multi-purpose device.

When little Hans is elsewhere, the seat back folds flat, which not only does wonders for the drag coefficient, but produces a wide rack suitable for carrying all manner of awkward things home from B&Q.The seat back also incorporates a steel frame that can be folded down behind the seat to create a longer load platform, or some vestigial luggage capacity when the seat is occupied.

…The Junior weighs 4.8kg, even before you’ve mustered the podgy ten-year-old…


We fitted the Junior to the long- suffering Ezee Sprint, the various fixtures and fittings coping reasonably well with the slightly unusual geometry of the bike, so it should fit most conventional diamond frames. A few tips here: the frame tubes have to be clean and grease-free (that includes spots of road tar), and the bolt threads should be lightly greased.Tighten the fixing bolts, ride a few miles with the seat under load, and re-tighten everything, because the clamps are fitted with plastic bushes that take up a bit of slack as they ‘run-in’.

Bobike Junior Child Seat

Highlighted in black, the support structure is clearly well in front of the child’s weight

Usefully, the Junior shares a quick-release system with its smaller cousin the Maxi. This means that children of various sizes can be accommodated on different bikes as and when required.The seat is secured by engaging the nose in a connector bolted to the seat tube and plonking two struts into a pair of brackets secured to the chain stays.This produces a triangulated structure, but unlike a conventional rack, which generally puts a pair of struts under the load, the supporting legs of the Junior are positioned well forward of the seat.When the child sits down, the seat base bends down and back, putting far more strain on the assembly than is really necessary. Fortunately, the mountings and bolts are the type used to secure truck bumpers, but we never really worked out why it had been made this way. Another slightly odd feature is that the manufacturer assumes you’ll be keeping the luggage rack in place under the seat, which seems like a lot of unnecessary weight (a kilogram in our case) when you’ve just bought an expensive child carrier and rack combined.The Junior weighs 4.8kg, even before you’ve mustered that podgy ten-year-old, so you’ll probably want to remove the rack, as we did at first.

The odd geometry, plus the rather woolly plastic joint bushes, make the thing feel a bit insecure. From the sharp end, we’re told this is great news, or as Alexander puts it cheerfully,‘a seat with s’pension’. He’s right up to a point – the Junior does a good job of cushioning road shocks, albeit by the slightly downmarket expedient of bowing and flexing.

Is it safe? Yes, but bear in mind that a child hanging off the side making rude noises at his friends will cause a lot more strain than a heavier child reading a book. Alexander weighs 22kg, which is well within the 32kg limit, but his weight makes the Junior drop by 4mm, plus another 3mm or so on the bumps. So for us, the chair needs to be at least 10mm clear of the mudguard or rack to avoid noisy contact on bumps. A heavier child and/or luggage will need greater clearance unless the seat were deliberately allowed to rest on the rack. In the end, we refitted the rack and allowed it to do just that.

Another area that cause us slight concern was the lack of leg protection.We’re used to a child seat with moulded plastic sides that make it impossible for the child to put a foot anywhere near the wheel.This omission on the Junior was puzzling until we read the instruction leaflet; ‘Fit Bobike foot protection plates if your bicycle is not fitted with dress guards’. Dress guards are rare in the UK, but we’d strongly advise fitting one or the other.

Similarly, the safety harness is a bit wimpy, and rather poorly mounted on the top of the seat back, which will – in any event – fold forward under stress.The front mounting is better, but the buckle may prove a temptation for small inquisitive fingers.The belt also has a tendency to fall off the shoulders, something that can be improved by crossing it over behind the child’s back.With no sides to the chair (again, this is something we’re used to) we’d really want to see a better safety harness. After a fun-packed day chasing granny’s sheep, Alexander usually falls asleep within ten minutes, and a sleepy child will sag forwards, backwards or – most unnervingly – sideways.


We were prompted to look at the Bobike Junior because we were worried about the integrity of a cycle rack for carrying larger children, but we’re not convinced this folding seat does a better or safer job. In some areas, such as the footpegs, it’s massively engineered, but in others it doesn’t seem man enough for the task. Of course, we have one large child – for larger families juggling awkward logistical problems with several smaller ones, it could be useful, especially if you already have a Bobike Maxi.

A to B child seat design

The A to B child seat of the future would fit on a standard rack

This design clearly isn’t perfect, but where do child seats go from here? Most ‘sensible’ bicycles have a rack, and removing the rack rather narrows your carrying options. So we’d suggest a moulded plastic bucket seat that clamps to the rack, but with extra stays to spread the weight of a child into the frame.We’d also suggest a two position reclining seatback, both for sleeping children and awkward luggage, but not necessarily folding flat, provided the seat can be fitted and removed in a minute or two.The harness has to be really good – preferably the five-point type.

Heavy and expensive, surely? Not in our experience. We’ve solved the six-year-old problem by putting some extra struts on a basic child seat – the final structure weighing less than 1.8kg. Even if a reclining mechanism doubled the weight, it would still be lighter than the Junior.


Bobike Junior Child Seat £85 (plus £15 for the MTB kit used on our bike) .Weight 4.8kg (101/2lb) Manufacturer Dremefa BV web www.bobobline.nl mail info@dremefa.nl UK Distributor Amba Marketing tel 01392 840030 mail sales@amba-marketing.com web Amba Marketing

Hedge Cutting

Legal Obligation for Hedge Debris

Hedge Cutting

Hedge cutting in Hardwick Lane © Michael Trolove

“How can a person encourage or force a landowner to meet their legal obligation to clear up hedge debris from public roads?” Robin Sheppard, Cowbridge, South Glamorgan”

The legal obligation on landowners to clear up hedges can be found in section 154 of the Highways Act 1980. As an aside, all references below to hedges also apply in relation to trees and shrubs. Where a hedge overhangs a highway or any other road to which the public has access to so as to: ‘endanger or obstruct the passage of vehicles or pedestrians’, or ‘obstruct or interfere with the view of drivers of vehicles or the light from a public lamp’, or ‘overhangs a highway so as to endanger or obstruct the passage of horse riders’, the local council may, by notice either to the owner of the hedge or to the occupier of the land on which it is growing, require him to within 14 days from the date of service of the notice to cut it so as to remove the cause of the danger, obstruction or interference.

A person aggrieved by any such requirement may appeal to a Magistrates court. Subject to any appeal, if a person on whom a notice is served fails to comply with it within the specified period the council may carry out the work required by the notice and recover the expenses reasonably incurred in so doing from the person in default.

If an ordinary member of the public wishes to make a complaint to the council in order to enforce the obligations of the landowner under the Highways Act 1980, then that person simply needs to call the council to register the complaint.The council will then send a Street Enforcement Officer who will serve the notice on the landowner.

Where the landowner fails to clear up hedge debris from a public road, an aggrieved person may be able to bring a claim for public nuisance. A nuisance can generally be defined as an act or omission which endangers the life, health or property of the public. The nuisance must materially affect a class of people who come within the sphere of the nuisance. It is not necessary to prove that every member of the class has been injured or affected. It is only a civil wrong and actionable as such when a private individual has suffered particular damage over and above the general inconvenience and injury suffered by the public. For example, a punctured tyre caused by the debris.

These days environmental legislation has made this remedy probably less useful than it once was. It does remain useful however where the injured party requires compensatory damages or where the public agency is not prepared to take action. However, enforcement of duties under legislative provisions is for the most part the concern of local authorities and other public agencies. In which case, if a landowner has neglected his duties and failed to clear up debris from his hedge, the first port of call should be the local council who will send round a Street Enforcement Officer who will serve notice on the landowner.
Judge Jefferies

Your legal enquiries are answered by Russell Jones & Walker, Solicitors – the best national firm servicing the needs of individual people, with branches throughout the UK. 

A to B 49 – Aug 2005