Treefox

Ok, so I recently acquired a new TT bike, which came with Mavic Ksyrium Equipe wheels. Fine.

I've since acquired two more rear wheels for races - A Mavic Cosmic Carbone and a HED disc (both used).

The HED disc has one of the slightly older shimano freehub bodies - the sort with threading on the outside on the ends of the splines (for older cassettes) and spines that go right to the end. But it's certainly not a 7-speed freehub; I can get a 10-speed cassette on it fine.

The Ksyrium and Cosmic are both probably 2006 models.

While I've messed around with 9-speed plenty, and built/repaired/upgraded my own road bike, I've never messed with 10-speed.

As I ought not to be able to put an 11-tooth cog on the older HED disc's freehub, I decide to move the 12-25 off the Ksyrium, to the HED, and use an 11-23 to swap back and forth between the Ksyrium and Cosmic.

So I pull the cassette off the Ksyrium and find not only the thin little spacer that also came with the new 11-23, but a thicker one as well, as seen on the left in this photo (both these spacers were on the Ksyrium as received from the shop - stacked together behind the largest cog):


I had thought that the thin little spacer was the standard 'spacer you'll need for 10-speed' (one came with the new 11-23 cassette I bought) - but when I try to put a cassette on either of the Mavic freehubs without the thicker spacer (just the thin one), the cogs rattle around. However, I can also achieve a mystical 11-tooth on older freehub on the HED with the thicker spacer.

Hmmm.... Now I'm a bit lost. And for the life of me I can't get all three wheels to work consistently. I can't even get the Ksyrium and Cosmic to both work.

So where should I be using these spacers?! And having never previously bothered with having multiple wheelsets to hand, was I naive to imagine I wouldn't have to readjust the derailleur when swapping wheels?

(now to make all this a true pain, I've been swapping things back and forth and testing with three wheels, two cassettes, only one of the thick spacer, and no proper repair stand.)

I should also throw in the caveat that I'm not 100% sure the largest cog in the cassette ever previously worked (it's a TT bike - didn't really need a 25).

Both cassettes are 10-speed Ultegra, for whatever it may be worth.

And there are some other assembly oddities on this bike, so the fact that the wheels came with two spacers stacked together may be just some strange whim of the guy who built it up - - it's not a stock model either; the shop built it up from a frameset.

Al1943

The thicker spacer is to make up for the difference between a MAVIC cassette and a Shimano cassette. The MAVIC cassette is wider.
The thinner spacer is to make up for the difference between a Shimano 10-speed cassette and a Shimano 8 or 9-speed cassette. The 10-speed cassette is narrower.
If you are using a Shimano 10-speed cassette with the MAVIC hub you'll need both spacers.
If you are using a Shimano 10-speed cassette with most hubs designed to be compatible with 8, 9, or 10-speed cassettes then you'll need just the thin spacer.
Certain late model Ultegra or D-A hubs will not need either spacer.

Al

Treefox

Excellent, thanks. Didn't know Mavic made its own cassettes.

Any guesses as to what I'm likely to need on the disc? Just the thin one, as it's not Mavic?

Annoyingly, that means I'll have to haul my lazy self down to the LBS tonight. Blah.

Al1943

Before I saw your second post I edited mine. I think you'll need only the thin spacer for the disk. Just be sure that the cogs hare held together tightly. Loose cogs can cause damage to the hub's splines.

Al

Treefox

Yeah, I assume the 11T won't work with just the thin spacer - but that running it with the thick spacer would've meant it wasn't catching enough spline to not have trouble.

Thanks.

Al1943

As far as stack thickness goes the 11 shouldn't be any different from a 12t. Of course with the 11 you'll need the special 11 lockring that is a smaller diameter than the 12.
First position cogs with built-in spacers will vary in thickness between 7, 8, 9, and 10-speed cassettes.