so im running a 33x12.5r15 mud tire on my FJ60 on the highway the tires are filled to 30 psi now my question is, in the mud, sand, ect. what psi should i air down to without having to worry to much about popping the bead? 
Psi?
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just askin why 36 psi?
REKCUT
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Before I went to beadlocks I would run 15 pounds without issues. I used to run 10, but with the weight of a wagon you can have problems when your off camber and facing down hill.you will end up with all your weight on on one tire and that can cause you to roll off the rim. I know several of the 80's I wheel with run 15 with no issues.
What's the width of the rim?
I run my 35x12.50's at about 10psi but like REKCUT said, I tend to burp air and get a flat about once a wheeling weekend. I'm running 10" rims and if I had 8" rims, it would be less of an issue.
I run my 35x12.50's at about 10psi but like REKCUT said, I tend to burp air and get a flat about once a wheeling weekend. I'm running 10" rims and if I had 8" rims, it would be less of an issue.
Check the manufacture's spec's. BFG MT 33x12.5x15 are rated for 35 psig maximum. running higher pressures may get you into problems later if you have a tire related accident and you are found exceeding the limit.
Like others have said, offroad I would run between 10-15, depending on the rim. Typically, I run about 12 on my 8" rims.
As for the highway PSI, you want to inflate the tire so that the entire tread lies evenly on the pavement. You can do the chalk test so that you know what the proper pressure is for your tire / wheel / rig combination.
Optimizing Tire Pressure
As for the highway PSI, you want to inflate the tire so that the entire tread lies evenly on the pavement. You can do the chalk test so that you know what the proper pressure is for your tire / wheel / rig combination.
Optimizing Tire Pressure
I have run 18 in my 285/75R16 on my 60 without problem. They're the equivalent to a 33x11, but I run them on a 7.5" wheel. If you're running a 8" wheel, you might want to stay above 20.
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If you're on 8" rims, and you keep your speeds low, there's no reason not to run between 8 PSI and 12 PSI. If you are going to travel faster than about 25 kph, then your pressures should be up a bit, and do not even think of going more than about 40 kph without around 20 psi in your tires.
Do not run low pressures at higher speeds - tires will get very hot and come apart, also you risk losing control of your vehicle.
~John
Do not run low pressures at higher speeds - tires will get very hot and come apart, also you risk losing control of your vehicle.
~John
At 35-36 PSI you are probably going to wear heavily in the center of your tire. Try 32-33 for the road and see what sort of contact pattern you are getting. Try the chalk line as has been mentioned. If you are doing some fairly agressive low-range wheeling, you will want to go as low as you can on the pressure, I wouldn't go below 10. My travels usually involve high amounts of higher-speed dirt roads with some wheeling in between, so going down to the lower end of the spectrum for that sort of thing doesn't work for me. I usually go down to about 24 PSI on my 35s and that works very well for my nomadic wanderings with a mixed bag of terrain, I don't feel the small road rocks and wash board ruts at that pressure. Saves me and the rig a lot of beating.