I just did an MTB biathlon yesterday which was 50% road (mostly uphill) and 50% off-road with some singletrack (muddy downhill). I removed the Continental 2.1 from my rear wheel to cut down on rolling resistance and put a Panaracer Trailblaster 1.95 with about 50 PSI on. I kept a Continental 2.1 (can't remember the name) on the front for better control on sand and gravel. I crashed out bad in the first lap because my rear tire slid out from under me on a downhill corner. (no serious injury) Did I do something stupid? What tire setup would you use for this situation?