Your tires are rated at 3195 pounds of load per tire or over 12,000 pounds total vehicle weight. You are likely running about half that weight fully loaded. A pressure of 30 to 35 PSI will be in the ball park for highway on road driving. The chalk test is a good ball park estimater. Off road, we have run that size tire (not that brand though) on both M/Ts and A/Ts as low as 12 psi and have never had a tire come off the rim. Most tires have very close tolerences for fit, so unless you are on extreme rock crawling trails, you can run low pressures on dirt, snow, ice, mud etc. Heat build up is the issue, and at low speeds on soft surfaces, heat is not a factor. On the highway, heat build up is a big cause of tire failure, and low pressure is usually the cause. We have run the same tire sizes on the highway at 30-35 PSI with no overheating issues at all, so you should be very safe in that range of tire pressure unless you run an unusually heavy load in your JK.

 

Are you saying temps at 30-35 when the tires are cold or at road temperature?