I run mine at 71-75 all the time. Big diff in MPG.

 

Last I knew anything, tires were designed to be able to handle the pressure increase from the normal heat of running; indeed, most tire manufacturers will expressly warn against de-pressuring a hot tire. (I seem to recall that the standard figure was that for every 10 degree increase in COLD inflation temp, you'd add 1 PSI of tire pressure.)

Most pavement temps run 110-120 in "normal" temps, and between 140 and 170 in the desert southwest where air temps are in the 110's and 120's. Again, tires are usually designed to run at this temp, as long as they're not overloaded or dry-rotted or otherwise damaged.

I would submit that if you're smoking/melting/burning/blowing tires in Maine, you've either got other problems elsewhere (bad brakes? bearings? alignment?) or you someone who didn't know what they were talking about sold you an incorrectly-rated tire -- perhaps a P-metric tire in a C-load range, but the correct size.

Something else to keep in mind is that many manufacturers have a maximum speed rating on their tires, and I've seen many RV tires that are rated at unrealistically low speeds (like 45 or 55 MPH). If you're routinely pulling down the road at speeds in excess of 65-70 MPH, you may want to investigate the purchase of (assuming) E load-range truck/car (as opposed to trailer) tires that are at least H or S rated for speed(130 MPH). They'll likely be nearly twice the cost up front, but it'll save you more headaches of this type in the future.

(As an aside to this, I'll never run anything but Bridgestone or Yokohama tires on the Freightliner; they're the only G- or H-load range tires rated to run at 75 MPH; every other one is only rated at 65 MPH.)

-blaine

 

Good advice Frankinbiker.

 

This debate has gone on in my family forever. Recently my brother inlaw started working for a major tire distribution company and he was sent for some Track time down in Arizona for a day of testing with Bridgestone. While he was there he asked the Tire Design Engineer what was proper (55 in the front and back, 70 when loaded.....). This was the reply from the Engineer. "Run your tires at the recommended inflation pres on the tire sidewall. If you do not you are damaging the tires sidewall and may experience failure when under load". Have been running that way ever since. Just my $0.02.

 

In my 07 with 325/60R18 Goodyear Silent Armors (65psi max on the sidewall) I run 60 psi all the way around. Rides better than 65psi and good nice, even wear. The rears would ride better unloaded at a lower psi.....but I often have 1500-2300lbs in the bed or towing ~10,000lbs so the 60 psi works out the best.


On my 01 with 38/15.50R20 Dick Cepek Mud Country tires (50psi max) I run 45 psi front and 40 psi rear.....truck never tows or hauls a lot of weight.



As for damaging the sidwall with too low a psi.....while it is possible in truck tires if you run waaaaayyyy low, it's more of an issue in car tires that have a rec. inflation psi on the sidewall.
Truck tires are rated fo X number of lbs of weight at X psi.

 

I was just repeating what an actuall tire design eng. told my brother inlaw and he specifically asked about truck tires not passenger car tires.

 

Good two cents worth. As a matter of fact your two cents worth will result in lots of dollars saved. I've been doing just that for forty years since I got tired of replacing tires that wore out too fast. By keeping them at max inflation presure the tires wear much longer saving bucks. However, you won't get as cushy a ride. My last five tires on my F150 I replaced after 95,000 miles. Those and cast aluminum 17 inch rims were a four hundred dollar option at the time I ordered the truck from the factory. Pretty good mileage for factory tires huh?