Tim Hardy ran his Boggers at 0psi for a week or two to break them in on his Samurai.
I've never heard of using diesel though. It depends on what your definition of "softer" is, do you mean the actual tread or the sidewall for flex or what?
A forum community dedicated to custom off-road vehicle owners and enthusiasts. Come join the discussion about trail reports, builds, performance, modifications, classifieds, troubleshooting, fabrication, drivetrain, and more!