Down here in deepest Kent we seem to get a unique type of mud. Its a mixture of clay and sand and froms a deep, gloopy slurry that varies in consistency from liquid silt to superglue. I've found a tyre that will tackle it though the Bontrager cuts through and somehow finds traction in even the worst of it, I'm very impressed. On the road they're noisy and slow as you'd expect and I have no idea how they'd perform on rock although I suspect they may not be that good due to the big blocky tread pattern. If you want a specialised tyre for real mud-plugging I can thoroughly recommend these. Price IRO £20.00 - £25.00 each.