Swapping Cassettes...

not sure if Aksiums are 10 speed only (my bike knowledge in that respect is a bit slim),

However if they are, the 10 speed cassette will have a spacer behind it, which if you remove the cassette and spacer then an 8 speed will fit on without a problem (sounds odd that an 8 speed cassette is thicker than the 10 speed to me but well thats the way it is i think)

I do remember reading something about some wheels having an extra spacer that needs to stay on, but someone can give you the correct info on that.

I'd guess Aksiums have a similar Mavic hub to Ksyriums, i.e. a Mavic M10 hub, which allows them to take Campag-spaced cassettes as well as Shimano ones.

Campag cassettes are wider than Shimano, so to fit Shimano to the Mavic hub they'll have a Mavic spacer (basically a big washer) perhaps 2mm thick between the cassette and the hub when you fit a Shimano cassette to them.

A Shimano 8sp cassette is the same width as 9sp - the cogs are thinner on 9sp, but the whole block is the same width 8sp & 9sp
A Shimano 10sp is narrower, as Will says above, so if a hub takes Shimano 8/9/10sp you have to fit a spacer with a 10sp cassette, which is supplied with a Shimano 10sp cassette. A Shimano 10sp-only hub will only take 10sp cassettes, doesn't need this spacer, is too narrow for 8sp/9sp.

So if you take the 10sp Shimano cassette off your Aksiums, you should find *two* spacers, the thicker one is the Mavic one and you'll need to keep it to fit your 8sp cassette, and a thinner one for your 10sp cassette which you'll need to remove (and use with the 10sp cassette on your new Summer wheels, assuming you're transferring the 10sp cassette to them and they're 8sp/9sp/10sp)

heres what you need.
in facrt this should be a faq sticky really
all you ever needed to know about cassettes
and not forgetting Sheldon

aracer wrote:

Wow - that really is a handy link, peanut - thanks for that (bookmarked)!

have to echo that cheers peanut