Why is my used Ultegra 10-sp cassette wobbly to the touch on a new Ambrosio hub? All spacers present/correct and 11-sprocket well-seated before torquing 40nM lockring. I tried another (used) 10-sp 11-21 cassette on the same hub and there is no wobble for that one. Puzzled!

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    Are you 100% on the spacers? Have you read this? sheldonbrown.com/k7.html#11
    – alex
    Commented Jul 18, 2013 at 11:50
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    okay, I've sorta solved my own problem by fitting the 1mm '10-speed' spacer ring behind the cassette. No idea why its not needed on my other cassette, although the clue is here: slowtwitch.com/Tech/Cassette_How-To_-_Part_2_3257.html Commented Jul 18, 2013 at 12:24
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    x2. Every time I've had a cassette wobble problem, either I haven't tightened the retaining ring enough or I've misplaced a spacer.
    – JohnP
    Commented Jul 18, 2013 at 15:05
  • @VaVaVeteran that's a good article. I've seen this spacer before but never really appreciated its significance.
    – PeteH
    Commented Jul 19, 2013 at 9:57
  • Rereading the question, I noticed the wording "11-sprocket well seated". Note my answer, if the final sprocket is not above the freewheel, you will not get compression.
    – Ken Hiatt
    Commented Jul 24, 2013 at 5:01

3 Answers 3


Note: Different cassettes may need different spacers.

Unless there is a defect in the cassette or freewheel, it should not wobble (at all!) when properly installed.

Try removing and cleaning the cassette (a bit of dirt can cause it to get skewed a bit). When you put the cassette back on, make sure there is about 1 mm of cassette sticking past the freewheel hub before putting on the locking ring. If the cassette is not sticking past, then (just like a compression headset), you won't be able to tighten it properly and you will need to put additional spacers behind the cassette. Tightening a lock ring without the correct spacing can also easily strip the lock ring (which is better than stripping the threads in the freewheel, but will still ruin your afternoon).

If there is still ANY wobble, a visit to your LBS may be in order.

  • Just encountered a bike today that had a mix of 9 speed and 10 speed drivetrain components and inspection showed a loose cassette (it was a 10 speed). Shim (space) fixed the cassette. Doubt this had anything to do with the 9/10 mix, but I guess it could have.
    – Ken Hiatt
    Commented Jul 24, 2013 at 4:59

I ran into the same issue. I installed a new SRAM cassette onto my new wheels and the cogs were loose. After a few trial and errors, indexing gears, I realized I forgot to place the little black spacer first. Then cassette goes on after. It's those little steps that get looked over. Cassette is solid as a rock. Tight and shifting great!


There's a bearing that rachets between the cassette and the axle. If you are in a very low gear and crank hard up a hill, that bearing can get warped or crushed. (I did it, that's how I know). Bike mechanic can replace it ... they have the tools.

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    mmm...I would tend to think that is more a manufacturing defect, otherwise there would be riders all over the place in Grand Tours with wobbly cassettes halfway up Alp d'Huez.
    – JohnP
    Commented Jul 18, 2013 at 18:27

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