Sources of vibration at high speed in and around rear wheel I’m experiencing vibration somewhere in the rear half of the bicycle when descending at high speed (say more than 30 mph), and I haven’t been able to pinpoint the cause. Everything looks fine, everything I’ve tried wiggling seems solid, and nothing seems to be getting hot except the brakes and rim.

I’d like help figuring what, if anything is wrong.

I could try to describe my observations in more detail, though I hesitate to do so for two reasons. First, they are all fuzzy and potentially misleading, since it’s hard to examine the bicycle while it’s moving 30-40 mph, and it makes me nervous so I slow down and the vibration stops. Second, it seemed like it could be useful to have a checklist of things to look into when experiencing such vibration, that isn’t limited to my particular problem. (If it’s more appropriate for this community, I’ll edit this question to add my observations.)
Note: I've included things not at the rear of the bike as sometimes we think something is coming from one area when it's actually caused by another.

List of things I would check:


Wheels true and round without rubber (check dishing too, but unlikely to cause vibration)
Adding rubber (tire and tube) and inflating does not take wheel assembly out of true (some tires seem to float from side to side a bit and this can make things wobble a bit at speed.
Wheel attachments such as reflectors don't lead to excessive imbalance.
Accessories such as pump, water bottle, lock are firmly attached.
Check entire wheel assembly: spokes, skewers, bearings. Everything should be free of cracks, dents, bends. Parts that move should do so smoothly (bearings, freewheel). Things that should be straight should be straight (spokes, skewers).
Pawls inside freewheel engage and slip smoothly and correctly.
Frame is intact, no cracks or bends. Especially the chainstay and seat stay.
Fork is intact, no cracks or bends.
Headset is installed correctly, no play in steering.
Seat post is intact, no cracks or bends.
Seat post is tight to frame.
Saddle is tight to seat post.
Finally I would check the bottom bracket area. This gets a lot of torque and abuse so give it another look for cracks or fatigue.


Still a problem? Get an experienced rider that is comfortable descending to ride your wheel. Find a nice straight descent with no traffic.