Rear triangle keeps getting more off center every time I ride.
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Rear triangle keeps getting more off center every time I ride.
I posted this to r/bikewrench where the neckbeard council told me that I was basically being stupid and that I didn't know what I was talking about and that it was the wheel that was the problem and that I am just stupid for believing that the frame is bending.
I would really like to keep riding this bike and I want to see if the people here have any helpful advice on how to fix this. I'm pretty sure that it can be bent back due to it being a steel frame but I am not an expert on materials. I have seen the local shop bend back steel frames with a large piece of wood and it was successful. Would that work in this situation?
I would really like to keep riding this bike and I want to see if the people here have any helpful advice on how to fix this. I'm pretty sure that it can be bent back due to it being a steel frame but I am not an expert on materials. I have seen the local shop bend back steel frames with a large piece of wood and it was successful. Would that work in this situation?
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Did you determine that the frame was bent using any method other than the wheel itself?
#4
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Hard to believe, but if it is actually bending while riding, why do you think it would stop?
Bending it back on a regular basis is just going to result in metal fatigue/breakage.
It's your skull.
Bending it back on a regular basis is just going to result in metal fatigue/breakage.
It's your skull.
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I assume that if it is bent straight once, won't bent back again due to equal pressure. I am pretty sure that the frame was bent from factory as it is a pretty cheap one with bad quality control. I got the whole boke used for $75 at a co op.
#7
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I don't care.
As I said, it's your skull.
I'm done.
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So it's always been bent, AND it bends when you ride it, and whatever you've checked makes you sure it is bent? I'm thinking it's mostly the wheel, and the dropouts may be out of alignment. Take the wheel off and mount it backwards, or take a few measurements, or run a string on the triangle, then you'll know. If it's steel, getting it close to straight is easy, but if it has been indeed bending while riding, it is toast other than for brazing practice.
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I did the string test and I have flipped the wheel around on multiple occasions to check and both the frame and the wheel are straight. I guess because it is a cheap frame it is kind of deformed due to bad QC. Probably it bending even more is just my imagination as I've never measured it.
I measure the distance from the string to the seat tube with a tape measure and it was the exact same on both sides.
I measure the distance from the string to the seat tube with a tape measure and it was the exact same on both sides.
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Have you measured the axle distance before and after riding in those horizontal dropouts? The axle slipping in a dropout seems more likely than the frame bending.
Last edited by freeranger; 09-01-22 at 03:21 PM.
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Either crank down on the wheel nuts or get a new frame. If the frame is bending (although wheel slippage seems more likely), you'll just fatigue and weaken it bending it back until the whole thing snaps.
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The frame isn't bent.
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Add a pair of cheap rear wheel/chain tensioner adjusters. Then see if it cures the rear axle slippage.
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The "neck beards" are correct: the frame is not bent. Most likely, your wheel needs to be re-dished.
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Wheel slippage would tend to force the wheel to the left inside the frame. In the initial photos the wheel looks like it’s canted to the right.
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Exception if it's on the fixed cog (likely, since there's no brake) and OP likes to skid... wheel would slip the other way.. like the photo.
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But logically, pedaling forward, one gets tension to the top of the chain and loose on the bottom, but pulls the right side of the hub forward (and throws the wheel to the left).
Braking, one gets tension to the bottom of the chain and loose on the top. that should still pull the right side of the hub forward (and still throws the forward edge of the wheel to the left).
Now, skidding might pull the left side of the hub back, but the forward edge of the wheel still goes left.
Nonetheless, chainstay rub would be worse than steatstay rub in both cases. The OP seems to indicate seatstay rub.
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Ok, a couple of things... when you mount the wheel, are you doing it with both wheels on the ground? The wheel should naturally generally center between the seat stays with the upper dropouts resting on the axle.
My guess is the OP is actually trying to force the wheel to lean when mounting the wheel. Then when riding, it just settles back down.
A couple of things to look at.
Actually, the flipping the wheel experiment may help determine both uneven dropouts, or dishing.
There is a dishing tool that you can use, but it may not be practical if you aren't doing quite a bit of bike work and wheel work.
A good bike shop should have it though, and it would take less than a minute to check the wheel.
My guess is the OP is actually trying to force the wheel to lean when mounting the wheel. Then when riding, it just settles back down.
A couple of things to look at.
- Are the dropouts perfectly level? That may be hard to measure. If not level, it would be a construction problem.
- Is the wheel properly dished (locknuts centered on the hub). That might not be as easy to measure on a bike with horizontal dropouts, but try putting the wheel in backwards, and sit on the ground. Does the wheel still lean to the right, or does it lean towards the left?
There is a dishing tool that you can use, but it may not be practical if you aren't doing quite a bit of bike work and wheel work.
A good bike shop should have it though, and it would take less than a minute to check the wheel.
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This. Flip the wheel. If it's now closer to the other side, 90% probability the wheel needs to be re-dished. Until OP takes five mins to do this, there's little point in further speculation.