I’ve just swapped my wife’s wheels over on her Cannondale Topstone. The originals had a spacer behind the Shimano CS-HG700-11 cassette.

I put the spacer on the new wheels with a Nukeproof Neutron hub but not sure I should have, as I believe the cassette is mountain bike width and the new hub is too.

I had to wind the gear cable adjuster out by half a turn and it shifts fine.

Should I take the spacer back out? Will anything bad happen? I assume the lock ring might not be screwed in far enough, but it’s been ridden and is fine.

There’s no spacer on mine with a deore 11sp hub

Cheers, I whipped it back off to look. It does appear to fit without the spacer but measuring the freehub body it’s the same length as the original wheels, so I put the spacer back on 🤷🏻‍♂️

I’ve only ever needed a spacer on a HG hub when using a 52 tooth cassette large cog. Withoute teh spacer, the casette was touching the spokes. If you have a 42 or 46 tooth large cog, you should be OK. But if you move to one of the Deroe 11sp casettes with 51(?) teeth, you might need the spacer.