Guys, i have been experimenting with my new PJ Dirtgrips with the PSI in the tires. Basically i want them to last as long as possible with mostly freeway (70mph) driving. Anyway they are load range E so the max pressure is way up there, but i keep painting a line across the tread then taking it out to the road to see where the entire surface of the tire is touching the road, anyway i tried every 5 PSI from 45PSI, and im down to 32PSI right now, and they still ride more in the center than the sides, (the outside 3/4" doesnt wear the paint off), i am hesitant to let anymore air out, im going to leave them at 32PSI for now, My question is for all of you guys out there with 33" tires and greater what PSI do you run and how is the tear wear? Any experiance is greatly appreciated.
Jetjock16.

 

Hey Jetjock,

I have 285/75-16's (which I think equates to 33's) and I have been running them at 45 psi fronts and backs. I have noticed that the center of the tires are wearing much more than the outside. I have since aired down to 40 in the front and 35 in the rear. The tires have a good contact patch on the road now. I haven't had enough miles as yet to determine if this pressure is sufficient, but it seems to be a lot better for tire wear. The only negative is the reduced gas mileage...

Best regards,

Jeff

 

More important to tire pressure is the rim width in relation to tire width. Often the tire pressure is lowered to make up for a wide tire on a narrow rim, and it helps ride quality. What i am getting at is how wide is your tire in comparison to your rim, you really should look at this if you want your tires to wear evenly. The rim will stretch out a tire at all times but with just low pressure on a narrow rim once you start cruising the tire will bow up. Hope this helps.

 

BFT is right on that one! I run between 40 -44 psi on my 36x14.5 swampers because if I go below 40 the tire could pop right off the rim. I am running a 12"rim. I have been getting good wear at 42-44psi
I have noticed however that I have to rotate tires every 2000 miles they wear uneven QUICK! that is just mudders for you! hey Jet! I am going to do the same thing in a few months with the hangers system! but I dont want to go to a 38" tire yet do you like your 36's with that much lift? my truck will be the same height and tire set up as yours! any feedback would be great. OHHH and I am looking into stinless brake lines as well are they worth it and how much? your truck looks real sharp. Your truck made up my mind to go with the hangers! THANKS! oh 1 last question what gears are you running! oh 1 more ( heard that before) how much for the drive shaft lenghtening? ok htats it for now I think.

 

Hirolln: i love the setup i got, all my pics are from the first day i got it done and they are not very good, all get some new ones up in the next few days. i could easily run 38's with this setup but chose not to due to my truck is exacty at the legal lift height for my state and 38 PJs would put it an inch over the limit, I need to be legal cause i live on a military installation, i probably would have went with 38's had that not of been a factor, AND KNOW THIS: i did tons of reaserch on actual tire hieght and if you buy any of the super swampers tires or Mickey Thompsons the 36" PJ's are about equal in size to the 39.5" tires of those two companies, as i compared them all back to back at a shop that had all of them, so be aware differnt tire companies make the tires significantly different sizes for the same advertised size. As for the hangars, i love them, youll have to get a block in rear or another set of leafs to compensate. The drive shafts were : up front just lengthened 2" cost $100, the rear was just shimmed carrier bearing 4", at first, worked fine just had a shutter on initial takeoff due to angles, you will suffer this between 0-15mph, i elected to go with a One piece, custom made rear driveshaft with upper CV unit, cost $450, totally eliminated the initial shutter.

Any other questions, email me.
Jetjock16.

 

thanks for the info! how are those brake lines? that is next on my list!

 

HIROLLIN,

Your gallary says you have a 6.5" Skyjacker lift with 8" in the rear. Is that a special kit??. I thought Skyjacker only made 4", 6" and 8" lift kits?? Did you go with new rear springs or rear blocks? Just curious because I am gonna order the 6" Skyjacker kit w/ rear blocks this week. I'm still undecided weather to run 35"x12.5" or 36"x14.5" tires. I already have 16x10 rims. I'm leaning more towards the 35's (BFG Mud-Terrains) because they're cheaper. I'm just afraid the 35's might look a little small with a 6" lift. What do you think???
-Rich


2002 F-350 Crew Cab Lariat Short Bed 4x4, V10, 4:30 LS, Black w/ Med. Parchment Leather, Off-Road Pkg, Snow Plow Prep pkg, Heated Captain's Chairs, Towing Pkg, Privacy Glass, Rear Sliding Window, Power Telescopic Trailer Tow Mirrors, Auto Shift-On-The-Fly, Fog Lamps

Mods: Westin Nerf Bars, Front Side Windows Tinted, Bed-Liner, Tonneau Bed Cover, 16x10 Mickey Thompson Classic II Rims (not installed yet)

Future Mods: 6" Skyjacker Suspension Lift & 315/75 R16 BFG Mud-Terrains (coming soon), 1" Track Bar...

 

Actually the skyjacker lift is 6.5" they just call it 6" why? I have no clue! as for the rear I had a 1.5" block put in a month or so after the initial lift. The rear seemed to look lower as you can see in my profile pictures ( those were before the block) as for the tires my 36's even look small on the truck. But it all depends what you want! I have seen 35's on alot of 4" trucks I personnaly think the 35's will look a little small! But I am stuck on bigger is better that is why I am lifting again soon! :P

 

Wow, guys im gettin alot of mixed answers here, ive got 12" wide rims and the tires are 36x14.5's the rim is what the tire has printed on it
"recomended 11.5 inch rim" and im down to 32PSI, (where im leaving it for now) and still the outer edges dont touch the road, when i was running 45psi only the inner most 5" touched the road, so maybe the dirtgrips are a differnt type of tire than others?? I just know i would not be running 50PSI in them or even 5 under max >>like 70psi?? as some people recommended. Im soo confused and right before Xmas i gotta do a 5k mile road trip on these baby's so i want to get the PSI right.
GLAMIS here i come!!!!!!!!!!
Rob.