I’ve got a pro iii (should be the same as pro ii for this issue) and a weird problem.

BTW I’m absolutely positive it’s put back together ok and the spacers (esp the usual one) are in place and intact. And this started and got worse without me touching / changing anything.

So when I back pedal in the smaller cogs the chain just jumps over the cassette and there is huge chain sag.

In middle and bigger cogs its fine. I’ve rebuilt it since the problem started and absolutelty no change with new bearings / pawls / springs.

There is obvious scarring inside the DS spacer.

Off the bike its totally fine. Tighten the QR though and the freehub sits solid to the frame rather than spin with the wheel. I’ve tried it in the frame with no “seal” – no difference.

This is with new bearings in the hub and freehub. I think its to do with the QR spacer thingy – why is it getting scarred?

On checking the axle vs outboard freehub bearing – the axle turns without turning the bearing inner.

Any input much appreciated. Neighbours have started coming round to see what all the buzzing sound is!

There should be a spacer between the freehub and the hub. I assume that is there.

Yes- double and triple checked that.

you sure there isn’t a rear derrailleur issue that’s causing the chain to jam up a bit?

if you take the chain and cassette off and mount the wheel in the frame does it freewheel ok when you hold the freewheel by hand? If not I’d say it was an assembly/spacer order issue.

Thanks waswas – Ive taken the chain and cassette off to investigate and its still noticably stickier once I start to do the QR up.

Thinking about it overnight I’m convinced its got something to do with the scored / worn QR adapter.

I’ve found a pic of a new one:
http://www.chainreactioncycles.com/Models.aspx?ModelID=47535

there appears to be a slight lip on the inner of the silver spacer- presumably to press into the bearing inner race. Mine doesnt have this anymore – its totally flat – apart from the circular scoring.