I've had that happen too, but usually when I'm under 6psi.
I run 2 rim locks and when the tire did pop off the bead, it was just in one small area and it did'nt grow....It hasn't caused a problem in finishing the day's ride.
I have since switched back to the IRC and it hasn't popped off ever, even as low as 5psi...mabye Dunlop had a bad batch..."I don't know"
I am currently running it backwards to get a little more life out of it before I throw a new one on and I don't feel any reduction in traction.
Lastly...I ride in an area that has lots of roots and rocks, when it rains the trails get slimy and the hills get greasy...the trials tire would work every where except in the deep mud and on the greasy hills.
So, as a test I cut the tire and IMHO this has given me the best of both worlds, it just plain hooks up everywhere and I haven't lost anything in the roots, rocks or getting over wet logs.
I decided to go with a pattern that would still allow me to ride on the road so I left the center row of knobs alone. (see pick)
I lent my grooving knife to a friend when he saw me scoot up a greasy hill and we had to pull his bike up part of it.
He plans to experiment with a different pattern, removing every other left and right knob in a zig zag pattern, then we'll compair traction.
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