I like big tyres. My fork works perfectly well. My wheels are ok. But there’s a stupidly small gap between the top of the tread (XR4) and the underside of the fork bridge (Reba). Currently have ~17mm rims with actual 2.2″ tyres (ie big). Will switching to ~23mm rims (Stan’s Flows) make the tyre cross-section wider and squatter and thus increase the mud clearance from the miserable ~7mm I now have?

I’ve not measured this (I could at home tonight if you like, I have rims @ 23mm, 49mm and 80mm!) but I doubt it will make any difference, the OD of the inflated tyre is dependent Shirley on the circumference of the centre of the tyre, which doesn’t change.

I see what you’re getting at but would agree with cynic-al that it will probably make little differece to the height of the tyre

Logically I’m thinking a rim of zero width will cause the tyre to form a tall elliptical or circular cross-section whilst a rim that’s as wide as the flattened carcass (~6″) will make the cross-section very low profile indeed. Any experimentation much appreciated!