I run a Spesh Purgatory at the back and it works really well in Winter on the rear and in the Summer on the front. The sidewalls aren't too bad - I run them a little harder, but on a muddy ride a couple of weeks ago, they gripped like crazy and I didnt slip out once! I live in the Western Cape, so we have wet Winters here, and the ground can be anything from thick mud to clay to perfect loamy conditions.