reggieray

Got a Rival rear derailleur, 11-25 cassettte...I was swapping stuff around on different wheels and can't remember if there was a ring/spacer around the base of one of the wheels' freehubs...can't get the chain onto the smallest cog now and the rear derailleur is quite close to the spokes...BLEH.

reptilezs

most notable shimano 10 spd cassettes and mavic wheels

rogerstg

IIRC, it relates to some Shimano 10 sp cassettes. Regardless of that, If you don't use the washer where it is required, the cassette will rub against the hub flange when tight. It'll be noticable. FWIW, the problems you've cited are the due to poor derraileur adjustment, probably the high and low limit screws.

billDennen

" ... If you don't use the washer where it is required ... "
Where would one find out whether a spacer is required or not, other than by visual inspection? The data sheet for the hub, cassette, or what?

If it's by visual inspection, exactly what would you be looking for?

rogerstg

You don't need to see it, you'll feel it when you rotate the freehub.

BobLoblaw

I doubt it's an issue of a missingspacer behind the cassette. If you needed one, you would tighten down the cassette lockring, and there would still be play in the cassette.

Different hubs have slightly different freehub orientations. Sounds to me like you need a rear derailer adjustment performed by a competent mechanic and you'll be good to go.

BL

Chris_W

In general, 10-speed Shimano cassettes should have the 1mm washer behind them, but no cassettes from any other brands do. The key indicator is the deeper channels in the splines on the Shimano cassettes - they were made to be compatible with a very specific new hub shape for the 7800 hubs, which Shimano quickly gave up on. However, the spacer isn't always needed on all hubs, and if the cassette is tight when the lockring is tightened properly then there is no need for the spacer. If it is a Mavic hub, then a special Mavic spacer is always needed before any Shimano/SRAM compatible cassette.

Retro Grouch 

I wouldn't be surprised if a derailleur adjustment was needed after replacing the cassette. That's common.

When you say "the rear derailleur is quite close to the spokes," it makes me wonder if the derailleur hanger has been bent inward a skosh. That's about a $15.00 job and it can sure save you a lot of derailleur adjustment hair pulling.