So what is the deal with the ridiculous price of SS couplers? I read in another post that it was near 500 to get them installed. I am planning on building my own frame with some friends who have been to the UBI frame building class and wanted couplers but SS only allows for approved shops to install them.

Couple questions:
1. Am I missing something about the stresses at these locations, if someone can be trusted to make their own joint at the BB and DT why couldn't they do a joint at the coupler?

2. Are there any other companies that make couplers?

3. Has anyone made their own?

If you mean copying their design, those look pretty hard to make ... I'm pretty competent at making things but think it would be tough even with the right equipment, much less in a typical home shop.

Consider that if the S&S couplers are not installed properly that you will experience the worst kid of frame failure imaginable and serious injuries are probable.

S&S has to consider liability issues and as such will only let people who know what they are doing install them.

I work with a frame builder who is S&S authorized and installing these is a step above what an inexperienced builder will be capable of doing and most of his couplers go on tandems and longtail touring bicycles where the stresses are even higher.

The aligment for S&S couplers has to be dead-on. Misaligned couplers are subjected to a lot more stress than a simple misaligned frame. Imagine if the couplers were slightly off-angle in different directions.

They don't make enough of them to get the economy of scale. Stainless is much more dificult to work with.

Considering the complexity of the design and the precision need in manufacture, S&S couplers are very fairly priced. The $500 installed price includes the frame builder's time and skill. Particularly for a retrofit, the alignment must be very exact and this is not a job for the neophyte and certainly not for the first time frame builder.

When ordered with a new frame from a maker like Co-Motion, the couplers are installed in the top and downtube before these tubes are cut to final length, mitered and brazed or welded in place.

If you want to do it yourself, take a look into the Ritchey 'break away' style of bikes. They don't have the ridiculously expensive hardware, and might be possible to do a homebrew job of.

I've repeatedly toyed with the idea of using pipe fitting hardware as used in plumbing to make a bike that can be disassembled. Those parts are fairly cheap so one could pick up a pair of those and a beater bike for some real-life experimenting w/o breaking the budget. They'd be a lot less slick, and probably heavier than the real deal though.

If I ever get around to doing it, I'd probably get quite a kick out of the reaction from those who recognize the source of the parts...

If you ever do this and they break... send us a note how you are doing in hospital. Seriously! I do not think you really know what the stresses faced at such a joint are all about. It would be interesting (and expensive) to do a stress study of such joints. A Mech Engineering M.Sc. would be helpful..

Well, failure is always an option....

But I don't think you're familiar with the type of fitting I'm thinking of. Once you get up to the size required to be a decent fit for average frame tubing size you'll have some really chunky pieces of metal, with plenty of cross section area in all the parts. Sudden failure of that joint isn't worrying me at all.

Compared to all the rusty, crashed, cracked and otherwise compromised frames/forks I've ridden over the years, often unknowingly, I'd happily trust my safety to a recently installed and inspected 1" or bigger union coupling w/o any concerns.





I'd machine out the threads intended to go on the pipe ends, insert the frame tubing there and braze the fitting on to the frame tube.

They're available in steel too, if chunky brass for some reason wouldn't feel "safe" enough.
What I might wonder about though, is if the frame would stay in alignment well enough to be properly rideable, and if the added thickness of the fitting would somehow get in the way of the regular use of the bike.

Those fittings are designed to allow for a "watertight" seal between the two ends, they are not designed to maintain alignment between the pipes, in fact, they are designed to allow for slight misalignment and still maintain the seal. I doubt that you would get a sufficiently rigid connection using a universal joint. I'd suggest you join two water pipes with a Universal joint and then see how rigid the connection really is.

Well, as I said: "What I might wonder about though, is if the frame would stay in alignment well enough to be properly rideable, " so yeah. Vertically they're locked in position by each other, but sideways might be interesting.

But a catastrophic fail while JRA - don't think so

I never even implied a catastrophic failure, and in fact I suggested that you go ahead and try it out to see how rigid it is...

I've ridden in articulated busses and seen articulated railroad locomotives. An articulated bike might be very interesting.

Well, no. That was tmac100 who thought that was in the making.

Unfortunately I'm quite skilled at keeping myself occupied, this idea is quite a ways down on the to do-list.
Vertical rigidity should be pretty much unchanged. Lateral/torsional rigidity while JRA is probably OK too, but might be "interesting" while out-of-saddle honking. Might be possible to rework the parts to a more definite fit. Or maybe a dollop of coarse carborundum paste might provide enough friction to get the joint stiff enough.

Like this?

Anybody had a frame with dent(s) in the top and/or downtube, and had the frame fitted with S&S coupler(s) at the location of the dents in order to eliminate said dent(s)?

Seems to me this might be smart way to fix a dented frame while at the same time upgrading the versatility of the frame for purposes of touring and travel etc.

If it's possible/feasible, that is. Can't think of a reason it couldn't be done, at least with typical dents cause by "biff"against-a-guardrail type event as opposed to bad crashes where the tubing as whole is bent.

Awfully expensive method of dent removal. Also, the S&S couplers are installed in specific locations in the top and downtube to allow the bikes to be packed properly and to keep the coupler's extra diameter from interferring with the riders legs and feet while pedaling. You wouldn't want them too far forward in the top tube.

A simple look at the tensile yeilds of the materials involved will tell you that even a stainless plumbing union won't hold for long.

S&S Couplers are CNC machined zero-tolerance multi-splined joints milled from PH 17-4 stainless lugs with a tensile yield of 150,000psi, (1034 MPa).
Stainless plumbing unions are (commonly) ASTM A182 forged steel with a tensile yield of 39,900psi (275MPa).

I don't think the tensil or yield strength comparison is germain. S&S couplers are made of a very strong stainless steel because they have to have the hardness to absorb the required clamping forces and resist wear and be as thin and light as practical. Plumbing unions have thicker walls and more metal so the overall strength would be adequate. Their design is wrong but the strength would be adequate.

"Neophyte" is that a scene from the matrix? I love watching him dodge bullets.

I still think 500 is still rather steep, reasonable for a one off fab but at any reasonable quantity they are making decent profit. I am moderately experienced in manufacturing and have a degree in mechanical engineering. Maybe not quite a neophyte or a joe shmo garage tinkerer, although I have met tinkerers with more mechanical intuition than many engineers. In the end it is a bike, yeah there are some stresses involved but they are still relatively simple.

Putting them on before hand is a great idea though, thanks.

OK, then go into competition with S&S and sell yours cheaper. Let me know how it works out .

They are expensive because they are industrial jewelry. Take a good look at one and admire the craftsmanship. There is only one manufacturer so there are doubtless some economic "rents" being harvested, too.

For tandems, they simplify immensely the task of travelling, well beyond merely saving the airlines' oversize baggage charges. It's the ability to split a bike in two (or more) pieces to move it through airports and get it into taxicabs, railway coaches (in Europe), hotel stairwells, Good Samaritan motorists who realize they can give you a lift, and into your own small car at home for that matter. It is a worth-while convenience that you can't expect to come cheap....for a tandem. Not so sure I'd bother for a single: there are just too many other options for lugging them around.

S&S restricts them to frame builders who carry liability insurance. Suppose a frame failure led to injury and both the (uninsured) builder and S&S were sued. Under joint-and-several liability, S&S would have to pay the entire damage award, even if they were found to be only 1% liable, if the frame-builder was unable to pay his 99% share. So their insurers will prohibit them from selling to a "self-insuring" frame builder. Simple as that.

What does it cost to fly a bike, in the regular size bicycle shop box? Multiply that x2 (there and back) and subtract it off the cost of the SS couplers. That is the cost of taking your bike to a far off land and riding it all over creation. Do that a few times and those couplers are paid for.