Whoa...my cassette is wobbling!

Triathlon Forum
1

I have a pair of older Hed CX’s I use for race wheels. The front is Sonic and the rear is Shimano 600. Before my race on Sunday, I installed the cassette and gave it a good cleaning. While I had the bike upside down I spun the rear wheel from the cranks and noticed a very bazaar sight…the cassette had a noticeable wobble as it spun around. It was only noticeable at a decent rpm but it was clearly going up and down like a warped record. I didn’t notice any other part of the hub out of wack. I disassembled the cassette and made sure there were no gaps or gunk keeping it from lying flush on the hub (what do you call that spindle section that sticks out anyway?) and it all looked ok.

Is it possible the hub is bent or is it more likely the cassette is somehow defective? It is a fairly new Ultegra cassette. As far as I can tell the thing still shifts ok so no sure if I should be worried about this or not. Thanks for your expert opinion on this.

Mike

2

Mike, you said you already cleaned it and remounted it, but please try it again, or better yet, if you have another cassette, mount that one and see if its the cassette or the hub.

If I’ve got this right - if you bend the spokes or wheel from impact or pressure, the cassette will still spin straight it’ll just be off in alignment from the rest of the wheel. A warped/wobbling cassette could be caused by misalignment of the cassette on the hub, or MAYBE it could be the little thin metal shim/washer on the locking nut of the cassette could be damaged.

I’m no expert but I did just save 10% on my car insurance.

3

That is not to uncommon at all…I have seen spin deviation up to 3-4mm and noticed no real issues. If it is a freewheel style it is VERY common and is casued by regular wear.