The Max pressure is 35psi on those tires. Had it been summer the tire blocks would probably have started to tear. They did on my 990. I took pics and sent them to Heidenau. They said the max pressure is 35 and mine were over inflated hence the tears in the tire. They said they had seen lots of over inflation tears but no failures. 35PSI max, period. Even with 35psi my 990 would light up the tire like a top fuel car. I dropped front and rear to 28psi off road and it was better at finding traction. Look at your tires closely and look for tears where the knobs connect to the carcus.