Cassette shim
 

I have searched this topic and came away with unanswered question. Must a cassette shim be on the inside of the stack? All the posts relating to "pinching" the cassette with the shim technique call for the shim to be put on first then put the cassette on normally. I have found that on a recent build- DA 9 with a Mavic 10 hub, DA 12-25 cassette- that the alignment seems better if I put the shim on the outside of the cassette near the lock. I can hit 39-13 without 53 rub up front. I do not use this ratio much but again the center to top cogs line up better as well. Cannot do this with shim on inside. Thoughts?

Interesting question. Does using the shim on the outside of the cassette give the lock ring something solid enough to tighten against? Normally it tightens against the smallest cog which is steel and serrated to hold the lockring tight. The shims I've seen are either Al or plastic and may be too soft to hold the lockring.

When I switched from a 7 spd hub to a 9 spd hub I needed a shim for my 7 spd cassette. Well, not knowing which side to put it on I placed on the outside. The shifting has never been so good and the lockring holds tight as ever. I have been told that it should be placed on first though. But it works great with my triple, no rubbing and as I said the shifting is great.

The lockring is definately biting into the aluminum shim and providing a nice squeeze on the cassette. The ass-backwards setup that I have felt very similar to the typical stacking when I torqued it on. I am going to check it periodically. Any other mad scientists out there?

I think the shim will hold the lockring just fine in this scenerio, but it won't last very well unless you never remove your cassette. Periodically loosening and tightening the serrated steel lockring into the soft aluminum will kill the aluminum shim.

I thought the main reason for a shim was to use 11t small cogs on older freehubs that had splines that were too long so the cassette needed to be set further outboard. But I'm not familar with various botique wheels.

Does your rear hub + cassette need the shim? If not, leave it off. If it does need it, coudl you put it on the inner side of the cassette? If so, so that.

In this case the "shim" is the 4.5 mm spacer needed to use a 7-speed cassette on an 8/9/10-speed freehub body.

Timcupery,
Thanks for the input. Yes, the cassette hub does need a shim. I just want to know why the shim should be on the inside when the chain alignment seems(open to interpretation) better with the shim on the outside. The hub is a Mavic 10 I believe. I bought a cheap set of new Cosmos for training/weather wheels. I have an older set of SSC's that have the nine hub and no need for the shim. This is all new to me so sorry for the confusion on this end of the keyboard.

Is this set of wheels advertised as being both Shimano and Campy compatable? I have a set of Bontrager Racelites that have a shim that is used on the inside with the Shimano hub/cassette to maintain a proper chain line. My read on this is that the wheel is already dished for Campy and the freewheel hub can be changed to carry a Campy cassette which is wider than the Shimano cassette and doesn't use a shim.

There was a discussion a couple of weeks ago that touched on this: http://www.bikeforums.net/showthread.php?t=179395

Whoops, wrong answer. I read a posting further down this thread and thought that was the question the OP had asked. Sorry. He is using a 9-speed cassette on a 9-speed hub.

I guess the question I should be asking is this: How many diffferent shimano compatible hubs have there been since say '02. I am going to measure the widths of the hubs on the newer Cosmos hub with the older SSC hub. Like I said, my nine speed DA cassette fits well without a shim on the 02 SSC hub but has slop galore on the '05 Cosmos hub, hence the shim.

A friend of mine bought a SRAM 9 speed cassette that came with a shim for Shimano 8/9/10 speed hubs. He didn't install the shim and the cassette was loose even with a tight lockring. I guess SRAM cassettes need the shim that comes with them.