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I'm having a bit of trouble getting my back wheel on after replacing my chain.

There is a wobble once per revolution. It wobbles such that, if viewed from above, it appears to spin straight for most of the revolution then veers to the right briefly then back to straight.

Further, if I spin the wheel fast enough the entire bike vibrates a LOT. It is fixed-gear so the crank and chain are spinning at this time as well.

My procedure was as follows:

  • Spin wheel to confirm there is no wobble before starting any work
  • Break old chain off with chain tool
  • Connect new chain around frame (but not over the cogs yet)
  • Loosen both nuts on back wheel so I could get the new chain on properly
  • Put chain on over the cogs
  • Tighten non-drive side nut so front of back wheel is angled a little away from drive-side
  • Tighten drive-side nut with half-inch slack in chain (in each dir. vertically)
  • Loosen non-drive side nut, let it land where it wants to, re-tighten
  • (The last three steps were following this guide

My searching so far suggests that the wheel may be out of true, but I believe it wasn't to begin with -- is it possible my procedure above caused it to go out of true?

Is there anything else I can check?

  • That definitely sounds like the rim is out of true. How much deviation is there laterally? Is there any deviation radially? Changing the chain would not affect the wheel - unless you banged it around somehow. Do check that the tire is in straight. – Argenti Apparatus Jun 24 '18 at 15:51
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    Are you sure you're not getting a "tight link" when you reassemble the chain? – Daniel R Hicks Jun 24 '18 at 18:08
  • Pretty easy to check if your rim is out of true: bluetac or even chewing gum, a bit of creativity, and something like a pencil. However this is unlikely to be the only issue given the information. Furthermore, a LOT of wobbly tyres are simply, wobbly tyres. My front is about 1.5mm laterally untrue at the moment (I chose even tension and wheel strength over perfect true-ness) but my front wheel looks extremely untrue if you judge it by the tyre. P.S. A long time ago, I trued a wheel trying to make the tyre look straight. This was a very very bad idea. Took hours to get it right again. – Purr Jun 25 '18 at 2:54
  • Use your brakes (I do sincerely hope you use brakes even in fixie mode), to see where the wobble is on the rim of the wheel. – Fandango68 Jun 25 '18 at 4:09
  • Really sounds like your wheel isnt seated all the way in the dropout. – Karthik T Jul 25 '18 at 5:23
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The axle is a single piece and it has 2 functions. The first is to secure the bike to the frame but it is also the stationary part of the hub that transfers the forces on the frame to the wheel through the wheel bearings.

Since the axle is a single piece, Tightening the frame to axle bolts could be tightening the hub to bearing torque. The wheel will feel gritty when you rotate it.

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I wonder if there’s a tight spot in the chain, caused by stiff links or cog/chainring tolerances. Rotate the wheel slowly and find the spot where the rim pulls to the side. Now check the chain tension with the cranks in and around this position. If it is very taut then it could be pulling the wheel to the side every time the cranks hit this position. You would need to adjust the chain tension to allow more slack in this position, or replace cog/chainring as appropriate.

Or, that’s not the problem and I’m talking nonsense!

You can check the trueness of the wheel by installing it in the dropouts without the chain (leave that connected just hanging off the chainstay). Rest something soft plastic (eg tyre lever) against the seatstay and move up close to the rim. Check for deviations laterally and look for up and down rim movement too.

But there’s no reason to think you’ve put it out of true from what you’ve described.

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I'm guessing you might have the opposite of the problem that Stanley P mentions -- your hub bearings could be too loose.

Simple test: With the bike off the ground grasp the tire and attempt to move it side-to side. If you see/feel any "rattle" in the bearings then they are too loose.

With some "slow release" style hubs it's fairly easy to get the bearing adjustment mucked up when you remove-reinstall a wheel.

(This could of course be mated with an un-true wheel or stiff links or some such, the combo producing the vibration.)

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You have two problems. First, the rim is out of true. This probably doesn't have anything to do with the chain. Second, your cogs are worn. On a singlespeed the chain can't skip like with derailleur, but it will cause noise and vibration.

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