So this is my new setup having replaced the original Giant branded wheels on my Defy. Cassette is 105. So I have fitted the thick spacer that comes with the wheel as per the Mavic instructions. What about the very thin spacer that comes with the cassette ? Its 0.5mm thick max and was on old freehub. Fit it or not or not matter ? All it seems to do, understandably is alter the indexing a bit.

Thanks

Here you go

http://www.slowtwitch.com/Tech/Cassette_Spacers_2013_3978.html

Looks like the mavic spacer and the one with the cassette

Handy link, many thanks. I just realised that mine is a 105 rather than Ultegra so just edited title but same result, cheers

Definitely fit them both.

The spacer that comes with the cassette is necessary on any 8/9/10 spd compatible freehubs anyway, just not a select number of very early Shimano 10spd specific freehubs (in their wisdom, Shimano 10spd road cassettes are marginally narrower than 9spd cassettes!).

The other spacer is necessary anyway on all Mavic freehubs unless you’re running 11spd.

Thanks mboy. I fitted it anyway but wasn’t sure. STW succeeds again, ta