Originally Posted by
operator
Purpose of the 1mm spacer is either to allow proper rotation of the freehub or to allow proper compression of the cassette, since 10 speed cassettes are narrower in width than the 8/9 shimano cassettes. Your 10 speed cassette should come with the necessary spacer.
i guess we may be talking about two different things. are you referring to the thin spacer between the lock ring and cassette?
i totally missed the 10 speed reference. when installing a brand new 9spd ultegra on my bontreger wheel i had to use a spacer behind the cassette. without it, the reassess in the cassette went over the stepped portion of the hub and hit the spokes. i added a thin spacer to prevent the cassette from getting over the stepped freehub body and all was good. i am not sure if 10spd is the same