Kamloops last year. Found some videos of some boys riding in Kamloops. Riding Kamloops Style Riding Kamloops Style II Riding Kamloops Style III
A couple of guy do but they load up pretty quick in the slim. Most run the M7312 Maxxcross SI Rear. This tire has stiff side walls and pretty good cornering abilities. Plus I've been told if you get a flat you can still ride on it. I still like the Kenda K270 Dual Sport on my 510. I did pick up a Mitas ET-01 trials tire for the WR-125 it has the stiffest side wall of all trials tires.
Interesting. Might be running higher pressures than I do, usually the treads come together when on the ground and get larger when not on the ground. Or it may be that 'special' slime from the Pacific North West I've heard about