Hey guys! Just got my jeep back from the shop and had a 4.5 BDS short arm lift with 37x13.50r20 Cooper discoverer stt pro tires and 20x12 wheels. They recomended filling them with 48 psi. The ride was really rough on the way home compared to stock but Ive driven lifted jeeps before and werent as rough. What PSI are you guys running/recommend on the streets?

 

Have run my 37x12.50-17 Trail Grapplers at 30 for nearly 5 years and have 40k+ miles on them. At 48...you'll wear those things down quick! And you decrease the traction running them that high because the contact patch becomes that much smaller. So....yeah....48 is way too high.

 

Do the chalk test.

 

Thanks for the info! i could feel every imperfection in the road ill probably lower them to 38 at least

 

38? :eek:

I run my 37x12 at 25 / 23

 

I'm on 37"x13.5-18 Cooper STT Pro and run 26 PSI mounted to 18"x9" wheels. Doing a chalk line test across the tread, I actually should be lower being that the outer 2" of the tread don't touch the ground, but any lower and it triggers the ever annoying TPMS warning. So I compromise to 26, keep the TPMS warning away, and the ride is about like it was with the stock 32" BFG MT tires.

 

You have to expect a rougher ride with those small sidewalls. A 17" wheel size would have been much better. You will want to run somewhere between 25 and 30.

 

Great tire choice thanks though ill take your word. I had a small coupe which had a factory psi recommendation of 32 so i always thought bigger and heavier cars need more air. But ill be freeing almost half of the air in them. Crazy!

 

I run 24 in my 37x17s

 

With the 20" tires I would expect you to run mid 20's for a decent ride. I agree with above that 17" wheels would have been a better choice.