I just bought some Racing 3's along with a 12-25 10 speed cassette. The instructions that came with the wheels say that 11 & 12 cogs are not compatible with the hub. The instruction that came with the cassette says just don't fit the first spacer behind the 25 cog. So I've fitted the cassette and all looks well.......but two questions: 1. I can't change into the 12 cog, is this just an indexing problem? and 2. Would a bike shop really sell the cassette along with the wheels if they knew it wouldn't fit? I asked them to fit it but they told me something about not being able to fit it as it might damage something on transit.