Dahon Curve SL Folding Bike

Dahon Curve SL

Dahon Curve SL Folding BikeFirst published in A to B  60 – June 2007

Readers may or may not be surprised to hear that Dr Hon thinks A to B has something of a Brompton bias. Fair comment? We tend to find that those who adore the Brompton are happy with our coverage, and those who don’t are either suspicious or grudgingly accepting. For years , Dahon UK, fronted by Mark (son of Harry) Bickerton came into the latter category – Mark was wily enough to understand that if we did show signs of bias, our readers would soon give Dahon free publicity by complaining. This all changed last year when big cycle distributor Fisher Outdoor Leisure was given the Dahon account. Soon after, we picked up a whisper that a Fisher’s rep had been pushing the Curve, ‘nudge nudge, wink wink’ as a ‘Brompton Killer’. Great stuff. We duly passed it on (Mole, A to B 56), but a few months later, in November 2006, a furious Fishers settled on a policy of noncooperation with non-compliant magazines. The company would now invite ‘impartial independent reviewers’ to test Dahon bikes, and distribute these (presumably favourable) reviews to magazines willing to accept such ‘advertorial’. A to B , said Chris Raven of Fisher, ‘…compared every single other model out there to the Brompton. Most of the models in Dahon’s range have very little comparative relevance to the Brompton’. True, maybe, but in the case of the Brompton Killer, the comparison had come from Fisher, not us. And, whatever the company spokesperson might say, the Curve is undeniably a Brompton clone.

The Dahon Curve

You’ll be glad to hear that we’ve overcome these Stalinist restrictions by obtaining a Curve SL independently. We’ll do our best to conduct an independent and impartial review before the commissars cart us off to the Gulag. First, let’s look at price. The basic Curve model is the DL, with 3-speed hub and rear rack for a very reasonable £350, undercutting the basic Brompton C3E by £45 and the more comparable M3L by over £200.

The more upmarket Curve SL sells for £550, putting it right in the middle of a bevy of Bromptons – about the same as the basic 3-speed models, but much cheaper than the 6-speed. Significantly, it’s also £100 cheaper than the Mezzo d9, which in terms of looks and aspirations is probably its closest competitor. The SL comes equipped with a Sturmey Archer 5-speed hub, and has no rack, which superficially seems a bit of an omission for an extra £200. On the other hand, it’s lighter,and painted a snazzy battleship grey, rather than any-colour-you-like-as-long-as-it’s-red. So both the cheaper bike and the sexier lightweight demonstrably undercut the British bike. Round One to Dahon.

Weight is slightly less clear-cut. The SL is claimed to weigh 9.9kg, but our scales say 10.8kg. That’s some way off the claim, but a full kilogram lighter than the Mezzo D9. As for the Brompton, it’s a bit hard to judge, because no models are strictly comparable. The lightest Bromptons are lighter, but they only have two gears and cost twice as much as the SL. A more typical £600 Brompton would weigh 11 or even 12kg, so the Curve SL has a small advantage in this field as well, although the 12.6kg DL is heavier than all but the chunkiest Bromptons. It isn’t exactly a knock-out, and may have to be decided on points, but it seems Round Two goes to Dahon.

Adjustability

Saddle height has always been a weakness with the Brompton, although the company can provide a choice of seat-pillars to suit individual riders, and recent changes have increased the wheelbase, making the bike feel much roomier. The Curve has bars adjustable from 90-102cm, but we’re not sure they’re worth the complication, as we kept our test bike at the maximum throughout. More usefully, the saddle goes up to 103cm, which is higher than a standard Brompton, but shorter than Brompton’s optional extended seat posts. Oddly though, the 103cm height of the Curve saddle is lower than it appears because the bike has a strangely high bottom bracket, giving the pedals 12cm of ground clearance. We can’t imagine why they would want to do this, but it forces the rider to put the pillar higher than normal to get a decent riding position.The Dahon also loses out in having a much shorter wheelbase – only 97cm, against 105cm for the new Brompton. That’s a huge difference, and it makes the Taiwanese bike feel choppier on the bumps and generally more cramped. The Dahon should win this category with its higher saddle and adjustable bars, but we don’t think it does.

“…it lacks zip, pep, call it what you like, but we came home grumbling rather than smiling…

On the Road

On the move, we felt the Dahon was completely overshadowed by the Brompton. Why? We’re not really sure. The slightly smaller wheels and wider, low-pressure tyres don’t help, but the Curve’s Schwalbe Big Apples are actually quite good, giving a roll-down speed of 14.3mph, which is excellent for 305mm tyres. The SL’s Sturmey 5-speed hub certainly imparts a bit of ‘stiction’ into the drive: they’re nice hubs, but there’s a distinct resistance in first and fifth gears. Frame flex? Well, it bends more than the Brompton, particularly side to side, where the Curve’s tall thin frame tubes count against it, but this only shows up when you’re really pulling on the bars. After looking over the Curve and the Brompton quite carefully, we concluded that the Curve’s high bottom bracket was part of the problem. You need to ride with the saddle much higher than you expect, and this is enough for most people to have difficulty in putting down power on hills. Whatever the reason,the Curve doesn’t possess that essential ‘feel-good’ factor on the road. It isn’t painfully slow – our ten-mile ride took a fairly typical 44 minutes – but it’s slower than a Brompton or a 20-inch Dahon,and the effect is most noticeable on hills, little hillocks feeling like the Alps.

Whatever the reason, we felt it lacked zip,pep, call it what you like, but we came home grumbling rather than smiling.

This round, and it’s arguably the most important, goes to Brompton.

Gears and brakes

The Curve comes with 3-speed or 5-speed Sturmey Archer hubs, which are more or less perfect for small folding bikes, but slightly limited against the range of 2-speed, 3-speed and 6-speed hub/derailleur hybrids produced by Brompton. As for gear range, there’s little in it. The Dahon 5-speed has a slight edge, with 225% against the 215% of the Brompton 6-speed, giving evenly spread gears from 38″ to 85″. The Brompton does slightly less well here, but it offers six gears, and the Brompton system is slightly more efficient than the 5-speed dual epicyclic hub on the Dahon,so there’s very little between them in practice. The Brompton certainly wins in terms of gear options, although not everyone is happy with the 6-speed’s twin levers. Neither bike offers very much gear-wise, but on balance, the Brompton set-up is probably more flexible and efficient.

Brakes are an area where Brompton is often criticised, and the Curve’s front and rear V-brakes offer much more powerful braking. This is thanks in part to the use of Jagwire cables, which reduce friction, resulting in a light and precise braking action. The brakes on the Curve are excellent. Unlike many modern V-brakes, there are no power limiting devices, so it’s rather too easy to lift the rear wheel with a front application, or lock it with the rear brake. But for most people, this light action and effortless power is the sort of thing the Brompton has never quite supplied. Another point to Dahon, making three each in total.

…The Curve’s brakes are excellent… Another point to Dahon…

Folding

This is generally regarded as the Brompton’s special feature, with the simpler fold-in-half Dahons coming in a poor second. This still holds true with the Curve, but the small wheels help a great deal, producing a long, low and relatively slim package. The folding process doesn’t take long, but you need to concentrate, something that isn’t really an issue with the Brompton, which can be folded at night, or in a thick fog, or while completely blotto, or all three. The Dahon handlebars must be rotated to bring the brake levers and cables up out of the way, then – if the pedals are correctly positioned – the bars can be folded down against the frame, and the frame folded in half. Pedals are the now familiar MKS MTE which simply pop out when you squeeze a ring on the shaft. Actually, it seems they’ve been popping out a bit too easily, because they now come with a fiddly plastic ring, which needs to be removed before the pedals will come off. More cavalier owners will chuck it away on Day One, which MKS no doubt appreciates.

The folded package now measures 67.5cm tall x 76.5cm long x 34cm wide,giving a volume of 176 litres, or six cubic feet. That’s getting on for twice the Brompton volume, and slightly bigger than the Mezzo. The package can be significantly lowered by removing the saddle stem and storing it between the frame halves, reducing the height to 52cm and the volume to 134 litres or 4.8 cubic feet. That’s still some way from the Brompton volume, but usefully lower,which can be very handy (the Brompton stands 58.5 cm tall). Unlike the Brompton, the package doesn’t lock in the folded position, but two little magnets come together, which is enough to hold the frame halves in place, but they’re not secure enough to, for example, run down a railway platform carrying the bike.

Where folding is concerned, the Curve is the clear loser. It’s lighter than most Brompton variants, which helps, but it’s bigger and more likely to fall apart once folded.

Accessories

The Curve comes with a stand, nice big efficient mudguards and (on the cheaper 3-speed) a rack. This is broadly similar spec to the Mezzo, but it’s difficult to make comparisons with the Brompton, which doesn’t need a stand, and can be supplied with a rack, but doesn’t really need one of those either, most purchasers opting for the luggage system. So any comparison is likely to be in the area of options, which the Brompton positively drips with, from an ever-widening frame colour range,to dynamo or LED lights (now fitted as standard),alternative tyres,and that custom luggage system with a choice of neat bags. Dahon produce many interesting accessories, but very little targeted at the Curve, suggesting a slightly half-hearted assault on Brompton’s core commuter market. The key thing the Curve does have (now fitted to all Dahon models) is a little frame lug designed to take the Rixen & Kaul KLICKfix luggage system. This is similar to the Brompton carrier system: with a plate screwed to the frame you can fit a huge range of bags, from ‘small pet’ carriers to wicker baskets and panniers. Strangely though, Dahon doesn’t seem to have capitalised on this innovation. Bikes are not being sold with the KLICKfix adapter (0211R) and plate, so you need to buy the whole kit before you can carry luggage Brompton-style. There’s also a slight issue with the brake and gear cables,which would be obstructed by a large pannier. None of the dealers we contacted knew anything about the carrier plate or bags, and we had to do our own research.In fact,the adapter and plate only cost £11.40, although some of the luggage (like Brompton luggage) can be expensive. By contrast, Bromptons now come pre-fitted with a carrier block,and the company supplies a range of classy and practical bags.The Dahon system is certainly a great advance, but tracking it down has proved difficult, and we’ve yet to see one in action, leaving the Brompton to win this category by default.

Conclusion

Perhaps A to B doth protest too much, but for a machine that shouldn’t be compared with the Brompton, the Curve seems skillfully targeted at Brompton customers. In some ways it really is better: Price, weight and braking efficiency go to the Curve, but folding, rideability, gears and accessories go to the Brompton. The Curve is a pretty-looking bike, and by far the best 16-inch Dahon yet. And it really might have been a Brompton Killer, if it hadn’t fallen down in a number of key areas. Fisher might argue that we’re not comparing like with like, as the Curve was never intended to be a commuter machine, but that’s not the impression we get from the publicity. Nevertheless, the £350 DL in particular is a good buy if you are looking for something cheaper than a Brompton for leisure use, but we’re not convinced it’s up to daily commuting.

Specification

Dahon Curve SL £500 . Weight 10.8kg (24lbs) . Gears 3-spd Sturmey Archer hub Gear Ratios 38″, 57″, 76″ . Folded Dimensions H67.5cm L76.5cm W34cm . Folded Volume 176 litres (6 cu ft) . Maximum saddle height 103cm . Wheelbase 97cm Manufacturer Dahon  UK Distributor Fisher Outdoor Leisure tel 01727 798345 mail dahon.service@fisheroutdoor.co.uk

A to B  60 – June 2007

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