I have an 06 f150 that i just put some Cooper Discoverer STT 265/ 70/ 17 tires on and I have searched and received conflicting answers on the correct psi. The tires are a Load Range E and have a max of 80 psi. The truck calls for 34 psi front and rear but i have read from some people that the LR E tires should have a minimum of 50psi.

What would you recommend for PSI for these tire. Mostly Road driving with some offroad, really just like the look of Mud tires.

By the way the tires are not very load and they look great, i'll try an get a pick later.

Thanks Matt

 

I have been running load range E tires on the last two trucks at 40 psi front and rear with rotations every 5K. The first set lasted for about 60K and this set is just turing 25K with great wear (both BFG TAKO's). The 80 psi mark is really for a 3/4 or 1ton with one heck of a load. If you plan on hauling something heavy, just put around 10 more psi in and go. These 1/2 ton trucks really cannot use the max potential of these E range tires, so loading them up on pressure is just a waste.

 

Also having them at that high of a pressure also invites a lot of tire wear and a rougher ride.

 

If your vehicle had a TPMS set up, setup for those tires, the sensors would be set to go off at 46psi.
Do a little calculation. Your tires are probably rated at around 3000 to 3300lbs at 80 psi. 40 would make them rated at best 1500-1650lbs per tire. Your rear axle is rated to 4000lbs, or 2000lbs per tire. 50 would be a lot closer to that number than 40 is.

 

I just got a set of Cooper Discoverer ATR's put on. 275 70 18 LT load range E.
couldn't get a good answer on the PSI so I did the chaulk test and came up w/ 55 front, 45 rear. It still rides a bit rougher than the P tire as would be expected but, from my research, LT tires definitely require more PST

BTW, I have an 04 F150 FX4 Screw

 

Thanks for the replies. It seems the responses are as mixed as when i searched for an hour, maybe i should just try the chaulk line trick. What is the proper way of doing that? or i can just search.

Thanks Matt

 

I'm not good w/ the pics but, you can find them searching. I found a bunch searching google.

using what I found out, I tested with "cold" tires, then, used thick playground chaulk making an approx. 1" wide line accross the treads(sidewall to sidewall). I then drove a few hundred feet and checked the wear of the chaulk. If it wore off in the center only, I decreased the TP, made a new line and checked again. It took several attempt to finally come up with my PSI #'s. This may not be a 100% exact method but, I feel it's much closer than simply guessing.

From what I read, the front carries more weight and should have more PSI which seems to make sense on an empty truck. Also made sense to me, that if you typically ride empty and then add a lot of weight, you should increase the PSI accoridingly. Various sites also recommended highly against too low a pressure as it increases heat in the sidewalls which may lead to tire failure

I probably spent a good couple of hours searching and finally settled on this method. My father, an "old time mechanic" recommended 50 psi all around. The chaulk test proved him pretty close.

I also double checked PSI from cold to hot(mine went up 5 pounds which, is about right.Had it gone up a lot, that would indicate too low a setting.

Hope this helps.

 

Thanks Jimmy K

You have been very helpful and informative. I am going to do the chaulk test today on my lunch break. Also that was a great tip on the tire heat. I will be sure to check that.

Thanks again
Matt

 

JUst got back from doing the chaulk test and just like Jimmy K i came up with 45 rear and 55 front.

I've got about a 45 muinute drive after work today so i'll do a temp test and see where i am at
Thanks Again Matt

 

Glad to help. those settings should work for you as well.