The Chainlink

Sup eerybody,

So a little over a month ago, the seat stays on my 1985 Schwinn Traveler broke away from the top tube (pics below.) The welds just snapped after a mildly long riding day when I hit a tiny pothole on Paulina south of Cortland. I had converted this bike to fixed gear with a giant chainring and only had one winter on it. 

Anyhoo, I've stripped it and built up another bike since but I have no idea what to do with this frame. I feel like welding it would be a temporary fix at best and that with any amount of regular riding it would break in the same spot. What about y'all? Does anyone have experience with something like this? Should I just take it to the scrappers and make a few bucks off of the cromoly or does she have hope of being ridable once more? 

Thanks in advance! I hope to see all of some of you at WNBR this Saturday!

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Depends on the condition of the seat stays.  Is the steel broken off or do you only see bronze showing through?  This bike was BRAZED together, NOT welded.  It's really a great way to put together a bike and most high-end steel bikes are sought after in this configuration unless weight is a primary consideration.

What are we seeing in the photo? Is that a big thick blob of brass only or did a chunk of steel from the seatstay crack right out of the tube? It looks weathered and even rusty. If that's brass only the crack was mostly open a long time.

If that's brass it's way too thick to make a strong joint. Kindest interpretation is there's point contact somewhere in the middle of the blob and the rest is a fillet. But it doesn't look good. Manufacturing error from the start. If the blob is steel that frame has been subjected to monumental stress sometime in the past 28 years. The next piece of steel over from the failure would be weakened too.

The stays are way out of position. Moved forward. Usually when a stay cracks it's only one and only a crack. Those get re-brazed. With all the motion that's occurred here you have to wonder what condition the chainstay and the dropout is in.

Off the top of my head I can't see why a giant fixed gear would cause this but....  Unusual uses create unusual stresses. This is an unusual failure. Giant gears mean giant torque and that's hard on all parts of the bike. Humans generate only a small amount of horsepower but make torque like a Harley-Davidson. Amplify that torque with a big gear on a bike that's designed for lightness and you have a problem.

That frame is not worth the cost or trouble of repair. If you want to continue what amounts to stunt riding don't expect the bikes to last forever.

I had the same thing happen to my 1987 Trek.  Jesse Hautau at Comrade Cycles did a great job welding it and it's been as "good as new" for the past 18 months of almost daily riding.

Lloyd at Blue City Bikes welded my rear brake bridge back on my 70's Motobecane Mirage.  Holding strong.

This is pretty fascinating!

Brandon, how big is the giant chainring? Bigger than a 52 or 54? I ask cuz this discussion of torque is making me wonder if I should swap in a smaller chainring on my currently fixed '88 Le Tour. Now I have something like a 52t chainring and 15t cog. I'm happy with it in general as I'd rather err on the side of torque, but I'm having some trouble with the bottom bracket. I guess the actual answer is to fix the bottom bracket, but I'm too incompetent to get the bearings out - especially on the fixed side so I've just been opening it up, re-packing it after which it works fine for a week or two... 

John C. Wilson said:

What are we seeing in the photo? Is that a big thick blob of brass only or did a chunk of steel from the seatstay crack right out of the tube? It looks weathered and even rusty. If that's brass only the crack was mostly open a long time.

If that's brass it's way too thick to make a strong joint. Kindest interpretation is there's point contact somewhere in the middle of the blob and the rest is a fillet. But it doesn't look good. Manufacturing error from the start. If the blob is steel that frame has been subjected to monumental stress sometime in the past 28 years. The next piece of steel over from the failure would be weakened too.

The stays are way out of position. Moved forward. Usually when a stay cracks it's only one and only a crack. Those get re-brazed. With all the motion that's occurred here you have to wonder what condition the chainstay and the dropout is in.

Off the top of my head I can't see why a giant fixed gear would cause this but....  Unusual uses create unusual stresses. This is an unusual failure. Giant gears mean giant torque and that's hard on all parts of the bike. Humans generate only a small amount of horsepower but make torque like a Harley-Davidson. Amplify that torque with a big gear on a bike that's designed for lightness and you have a problem.

That frame is not worth the cost or trouble of repair. If you want to continue what amounts to stunt riding don't expect the bikes to last forever.

This seems pretty similar to the recent breaking of my 1987 schwinn voyaguer.  I'm busy today, but I'll load some pictures and a write up of possible failures modes later on. 

It's a 58t chainring. It looks like brass that's left on the frame, but I'm not positive; it's worrisome that what's remaining on the top tube fits puzzle-piece like back with the seat-stays, which makes me think it could be steel. It certainly shifted forward when it broke which makes me think that the chain-stays are now bent and weakened as well. Looks like my little blue Traveler will be going to that great Velodrome in the sky. Thanks for the tips, everyone. I didn't hold much hope in the first place, especially when I brought it into the shop and everyone's reaction was "Holy shit! How'd you do that?" Buts it's nice to hear others experience.

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