The radial puts a flat patch on the ground by way of it's design. The bias ground patch can bend and wiggle because of it's design.
The sidewalls of MOST bias plys will withstand more punishment than MOST radials.
The radials are always more comfortable to the rider than the bias ply.
My choice will always be one of the STRONGER radials.. Goodyear and Firestone both make really heavy duty off road radials. So far I have went with the Firestones but the goodyears may be next.
Big JIm <img src="/forums/images/graemlins/pfft.gif" alt="" />

professional bovine relocation specialist