Got a question about my dad's truck.... He just bought a 98 F-150 4x4, offroad package, Triton, all that.
He just out a set of BF Goodrich Rugged Trail T/A 10 ply 265/70/17 tires on it, and is a little confused...
The door plate/tag on the truck says 32-35 psi, and the tires say max 90 psi.... he's got them all at 45 at the moment. what is an ideal pressure for on-road driving with little/no payload?
thanks!

 

Hi there!.......The inflation recommendation on the door sticker is pretty much only for the tires that came with the truck. The maximum inflation is just that .....maximum. I'm sure you'll get lots of opinions on this, but to my mind 45lbs seems a little high if you're not carrying any load. I run my BFG 285/75/16's at 38lbs all around on pavement. If I'm going off the beaten track I'll usually drop them to 20 lbs or so. You might get exagerrated center tread wear at 45lbs. Bear in mind that on radial tires its normal to have a bulge in the tire......they are not necessarily under inflated......take care hope this helps Phil

 

I keep my 265/75/16s at around 35-40 all around (back tires usually 1-2 PSI lower)

 

I keep all my tires at 35 psi...265/70/17"....Been everywhere and it works well...the tires are wearing even and I get a good ride and gas mileage seems better as well...

 

It sounds like you are running LT265/70-R17 load range E tires. If you are the 45lbs is about right or even a little low. Load range C and D tires run lornmally at the 35-40lb ranges. Load range E's are higher. I used to run load range E BFG ATs at about 48-50 lbs when I had them. Tire wear at the pressure was normal.

 

Man, you guys run low pressures......... Well, IMO you do.

My question is why get Load range E tires for a 1/2 ton truck?? Even D's would be overkill.... You'll exceed the axle ratings long before you even get close to the tire limits. Also, the stock wheels are only rated for up to 65 psi anyway.... That's what a D max COLD psi is.

I've got C's and the max COLD psi is 50. Empty, I run the fronts at 46 and the rears at 42. If I'm loaded up or towing, they all go to 50....

Did that on my last set of "40,000 mile" tires and got 60,000 out of them and they still had quite a bit of tread left... Center was not worn any more then the rest of the tire. I just wanted new tires!

IMO, heat is what kills tires. The lower the psi, the hotter the tire gets. Sure, the tire is rated for various loads depending on the psi, but why max out the load on a tire with a given PSI and have it run HOTTER then upping the psi and having it run COOLER....

I don't have a fancy infra red temp reader, but when cruising at my "empty" weight psi, the tires 'feel' as warm as they do when I'm running my "loaded" psi, but I have more load on them..... I know there's tons of variables that I'm missing between the two "tests", but in general, I have found that running a lower psi creates more heat for a given load then a higher psi for the same load...... On my trailer, it has these wimpy Load range B tires..... 35 max psi...... I ran them at that and did my 'feel' test on them and they are on the warmer side of 'warm'. I checked the hot psi, just for fun, and they were at 48 psi. I then set them to 40 COLD psi and ran them. They felt much cooler then they did before and the HOT psi was 50 psi..... Only 2 psi difference, but the temp difference was very noticable. The outside air temps were even HOTTER then the first check......

This is just what I do and I'm in no way saying this is what you have to do......

I'll probably get told that running my trailer tires with too much cold psi is just a blow out waiting to happen, but I only know what I've seen and I do plan on getting the load range C versions of the trailer tires so that I can run 50 psi in them at that point!

Good luck!