I just put on some Nitto Trail Grapplers (295/70R18) via Discount Tire. I checked the pressure and they set it to 45psi and needless to say I feel every pebble on the street. So, my question is what does everyone set their tire pressure to for the street? And, while we're at it...what do you set your pressure to for rock trails, rock crawling and also sand?

Thx!

 

I would drop them down to 35PSI and chalk test them for street. For trails/rocks/dirt I would start about 15PSI and see how they wrap and conform. For sand I would start at 10PSI and go down more only if necessary. On my old Jeep for sand I have gone as low as 6 pounds with 33x12.5x15's on 10" wheels. With the JK on the stock 255/75/17's I took them down to 10PSI in the sand and they were nearly riding on the rim so I went back up to 14PSI. I havent had the 37's in the sand yet so I cant comment on them.

 

I would drop them to 30 psi and do a chalk test. I run mine at 26 psi cold.

 

What is a chalk test?

 

You run a piece of chalk or powder accross the tread and drive it to see if the tread is wearing evenly all the way accross the pattern.

 

Thanks for the feedback. I just chalked the tires after setting the pressure to 32psi. In regards to the chalk test, how long do you run before noticing the wear? Is this something that would show after less than an hour of driving time or does it require more time?

 

Should only need a couple hundred yards.