S&S Couplings

S&S CouplingsLiving without a car brings its own joys, but add a tandem to the equation and life gets more complicated. Given the attitude of most train operating companies to tandem carriage, long distance rides are tricky indeed. My wife Anna and I planned an epic from Portland Bill in Dorset to John O’ Groats in the far north: ride up, train back, simple. Except that the Thurso-southwards train doesn’t take tandems, and nor does the Scotrail bike-carrying road van which runs parallel to it in the summer.

What to do? One very pleasant, but decidedly round-about option, was to hop on a boat to the Orkney islands, transfer to the overnight Stromness-Aberdeen ferry, and then board the mainline GNER service next morning; and that would take tandems, as long as we bagged the one space quickly enough. It remained the preferred option until pressure of work forced us to cut the trip short – now Anna, myself and ‘Black Lightning’ would be boarding at Glasgow. So we were back to square one.

S&S Couplings

Eek!! With the frame carefully marked, a short section is cut out of each tube

But trains do accept folding bikes (even tandems), so another solution presented itself – fit S & S frame couplings to the bike.The couplings are precision-made stainless steel threaded lugs that allow any full-size frame to separate in 60 seconds or so. American Steve Smilanick invented them about ten years ago. He was due to board a Mediterranean cruise, and wanted to take his Bianchi race bike along for 100- mile day rides while other cruisers were lolling in port. With a degree in Industrial Technology (not to mention his own machine shop) he had no trouble designing and producing the first S&S couplings.

S&S Couplings

Three pieces of tube, with the couplings behind

They worked so well that he went into business, and ten years later is kept busy producing ‘thousands’ (he wouldn’t tell me how many thousands) of the things a year, for cyclists who want the performance and rigidity of a full-size bike (‘cumbersome’ to A to B veterans) with at least some of the convenience of a folder.

Naturally, a couple of old Bickerton hinges pop-rivetted onto the frame tube wouldn’t do the trick, and the S&S couplings are impressively machined from solid billets of stainless steel.They do a 6Al 4V titanium version as well (for titanium and carbon fibre frames), an aluminium one (for ally frames) and even a chrome-moly coupling. All of these are intended for new frames, not retro-fit, and they come in various sizes, to suit most frames.The couplings are produced on a Mazak Multiplex CNC lathe; one of those all-singing, all-dancing machine tools. Solid bar goes in one end, and finished couplings pop out the other. For further and more detailed information, you can visit www.alliedexperts.com. Demand is such that this particular machine churns out nothing but Bicycle Torque Couplings, as they’re also called, though the company also makes specialised machinings for all sorts of other uses, including rockets.That might explain why some people insist that Steve Smilanick is an ex-NASA engineer; he isn’t, and never has been. Incidentally, you can’t just wander into your local bike shop, buy a set of couplings and fit them yourself. S&S will only sell the parts to recognised professional frame builders (they list 100, from all over the world), which underlines just what a precision job this is. St John Street Cycles of Bridgwater fitted ours.

…ordering from new makes sense, as fitting involves stripping the frame bare and repainting it…

Strong Nerve

That’s how I found myself ensconced in SJS’s kitchen (which appears to double as a wheel- building station) with Graham Tomlinson, who has been doing bikey things in Bridgwater for nine years. ‘I started off building frames for St John Street, but now I do most of their S&S work. It’s pretty seasonal, but I suppose it averages out at one or two sets a week. Most of those, maybe 60-70%, are for tandems, and most are on new bikes rather than retro-fits.’

S&S Couplings

Brazing the couplings into place

Ordering the couplings from new makes a lot of sense, as fitting them involves stripping the frame bare and repainting it. In theory, brazing only burns the paint off either side of the coupling, but St John Street prefer to repaint (or in our case, powder coat) everything. Once you have a bare frame, it really is a case of taking a hacksaw to it in exactly the right place, and removing a short section of frame tube, though I’d say it needs a strong nerve, keen eye and steady hand. Graham, thankfully, appears to have all three.

S&S Couplings

The finished frame ready for painting and reassembly - the three connectors must be perfectly aligned in the front tubes

‘I do the tubes one at a time,’ he told me; ‘cut, then braze on the coupling.That way the frame is always held rigidly in line by a solid tube – if you tried to cut all three at once, the frame would go all over the place.’ By now we’d been joined by Kevin Sayles, St John Street’s main frame builder, who settled down, mug of tea in one hand, banana in the other. ‘The brazing can be tricky,’ he added. ‘We use 55% silver braze, and that can be contaminated by the stainless. It’s tricky, but it can be done.’ The chrome- moly couplings are TIG welded rather than brazed, the metal plated to avoid corrosion and with rubber sleeves to cover the weld, and avoid the need for repainting. It’s cheaper than the stainless steel route, but intended for fitting to new frames only.

…Once fitted and tightened up, the couplings should be stronger than the frame…

Once fitted and tightened up, the couplings should be stronger than the frame tube itself. According to Steve Smilanick, tests have shown them to be both stronger and stiffer than Reynolds 531. ‘You can jump kerbs,’ he told me, ‘race downhill on a mountain bike, carry heavy loads while touring, crash the bike etc, it’s all no problem. In ten years, we haven’t had a single failure or return.’

S&S Couplings

Brake and gear cables need to be refitted with special quick-release joints

Well, I suppose that’s what you’d expect him to say, but the S&S website is littered with testimonials from people who’ve done epic round the world trips, with no ill-effects.That appeared to be backed up by a customer we met in St John Street’s showroom: ‘They’re terrific,’ he said. ‘I’ve had them fitted to my solo bike as well as my tandem, and they don’t make any difference to the ride at all – I can’t detect any frame flex.’ He might have added that there’s little weight difference either, as each stainless coupling tips the scales at just 115g, so adding three of them to a 18kg tandem won’t turn it into an overweight lump.

…we should be OK boarding trains that have a couple of normal bike spaces…

S&S Couplings

Final assembly is a big task, involving almost as much work as building a new machine

There’s one thing you can’t do with S&S couplings, and that’s fit them to a monotube frame, like that on the Giant LaFree. (Of course, even if you could, it wouldn’t do much good on the Lafree’s oval-section tubing – I have it on good authority that oval-shaped threads don’t work very well). According to Steve Smilanick, this is because the coupling is designed to cope with tension and compression loads only, as found on a conventional frame, not the bending components to which monotubes are subjected.They will work on a monotube recumbent though, or if the frame has a structural seat tube that connects front and rear halves together.

Practicalities

So, we now have a Thorn tandem with three S&S couplings, which allow the front third of the bike to part company with the rest in about a minute.You can have two sets fitted to a tandem if you want, splitting it into three parts (like Ancient Gaul, if you know your Asterix) but for train carriage (and simplicity) we thought a two-thirds/one-third split would be enough. As it is, the big section is about as large as a conventional solo, so we should be OK boarding trains that have a couple of normal bike spaces, but won’t take tandems.

Splitting is a simple process, using the C-spanner supplied with the conversion, though of course you have to split the cables too – one just puts them on the slackest setting (lowest or highest gear, as appropriate) and unscrew the neat little threaded connectors. Putting everything back together again is a little more tricky, and you really need an accomplice to hold everything steady, but with practice the couplings go together just as you would expect greasy chunks of precision-milled stainless steel to go together.

Being stainless, they won’t corrode, and maintenance is undemanding.They do need tightening periodically, and taking apart every now and then to remove grit that may have worked its way in – water won’t do any harm, but grit will.That, and re-greasing, is just about all you need to do.As for wear, you might expect the mating teeth to get sloppy over time, but they’ve thought of that too – the teeth are tapered, with a millimetre or two of clearance at the top of each one, so as wear takes place, the faces stay in close contact.

Now all this precision engineering doesn’t come cheap. Prices start at £350 (as an extra on a new Thorn solo) and retrofits (including the full respray) are from £500. Our tandem conversion cost £650 (three tubes to split on a tandem) which included powder coating the entire frame. Sceptics might say we could have bought a couple of secondhand Bromptons for the same money, but that’s missing the point.There’s something special about riding a tandem that you don’t get from any other two-wheeler – the speed, the team working – so having all that, and being able to stick it on a train for the journey home, is very like having your cake and eating it.

Peter and Anna departed for Scotland on Saturday 31st August.
Did the couplings successfully deceive Virgin Trains? No idea, but we’ll let you know in A to B 44

Contact details

S&S UK agents Bob Jackson Cycles tel (factory) 0113 255 1144 (shop) 0113 255 9844 mail factory@bobjacksoncycles.demon.co.uk . Kinetics tel 0141 942 2552 mail UKKinetics@aol.com St John Street Cycles tel 01278 423632 mail robin@sjscycles.com . Roberts Cycles tel 0208 684 3370 mail info@robertscycles.com . For a complete list of framebuilders worldwide, see www.sandsmachine.com or mail steve@sandsmachine.com

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