So I have Nitto Terra Grapplers on my truck, 285/70/17. The sidewall says the tires are rated at 80 psi. What should I run for pressure in them? I don't really do a lot of heavy work with this truck, or go off-road too much. Any help is appreciated.....

 

I will not be of much help but the 80 psi on the tire sidewall is for the max load the tires can handle, it dosent have to be run at that pressure at all times. I have "P" rated tires on my truck and run those at 40 psi all around with no funny wear or trouble. You may have to run a little higher psi in yours though but not the whole 80. Someone more knowledgable than I will be along shortly with a more educated answer.

 

so they are Load range E right? and LT rated

I personally would run 45 psi up front, 44 psi back


the on a nice hot day on level pavement, get a section of pavement wet for about 3 feet. the object is for your tires to do a complete revolution through the wet section

after about 1,000 miles look for even wear...it's a long process, but if you take the initial time and get a good pressure setup, you can optimize the tire life. Too much/little can kill a tires longevity.

 

Ok thanks for all the info guys. The guy who mounted my tires had them set at 45 psi, so I figured that would be close.

 

We had them on another truck. We most always ran 45 psi in them. Sometimes 50 if we had a heavy trailer.

 

I ran my Nittos at 45psi for hwy and 50 towing. Tylus, good explaination of tire footprint to tread life. Even a couple of psi can add thousands of miles of life to a tire.

 

45 works ok. Ive ran them anywhere from 35-50 for guys that drove their trucks lightly every day.

On your truck I would do 40 personally, but I seem to have the best luck with a few psi in my tires then most

 

I run 40psi and when towing I put 50psi in the rears.

 

Tylus gave you good advice and 45 up front is what my Cepeks take also.

There's another way to determine what you need, or at least a starting point. I got the Load/Inflation charts for the tires (available from the manufacturer and sometimes a tire dealer that's up on stuff). It tells you the inflation needed to carry a given weight. Go weigh your truck to get the individual front and rear weight Pull just the front tires on, record the weight, then pull off till just the backs are on). Unless you use a scale that can give you individual weights front and rear, you'll need to divide each axle weight by two. Compare that weight to the chart, rounding UP to the nearest weight. I usually add another 10 percent for safety as well, from experience. In my case, I use 45 up front and 28 in the rear (unloaded). I usually keep 35 in the rear at all times so I can toss a little something in, but I have a compressor on the truck for airing up for heavy loads. Since I just hung 350 pounds of winch and bumper up front, I now run 50 psi up front. My truck has an 8200 GVW, BTW.

 

Try one of the Cat scale locations to get your axle weights. http://catscale.findlocation.com/