Different thickness spacers behind Shimano cassettes - why?

[Globalti]

Bought a new 10 speed Ultegra cassette today and am surprised to find that it comes with a 1mm spacer to go between the biggest gear and the freehub, whereas my Mavic freehub has always had a 2mm spacer. Couldn't find anything in the Shimano instructions so I fitted the new cassette with the thicker spacer. Is there any reason for these different thicknesses or is it just what suits the setup?

Any comments?

 

[Cletus Van Damme]

I thought 10 speed cassettes were supposed to be thinner than 9 speed ones. I have Mavic Aksium wheels and have to use the Mavic 2mm spacer with a 9 speed cassette. Maybe you should of used both, unless there is no play.

 

[fossyant]

It all depends upon the hub. Mavic hubs use the spacers but they are 11 speed compatible already. Shimano hubs were not. So new 10 speed cassette might just come with a bigger shim for the new shimano hubs. Mad business for shimano on the hub design.

Hopefully you will have spare spacers

 

[Globalti]

It all seems to work with the 10 speed cassette and the 2mm spacer on the Mavic hub.