Ideal tire pressure for gas milage & wear ?

[1979 GMC Sierra]

Just curious as to what you guys feel is the ideal tire pressure for gas milage as well as for less wear and tear on the tires ? I have 245/75/16 tires on my truck. Max pressure on the tires is 88 psi. Right now i'm running them all on 70 psi. The gas milage on hwy driving seems to be decent, although the ride is a bit stiff on rougher roads. What do you guys think is best for gas milage based on your experience ? Is 70 psi decent...or should i go higher or lower ?

[bikes&bowties]

It depends on the tires... Such as on my bfg km2's I run like 25psi with a max of like 45... Generally more would mean better mileage and wear depends on how they sit either bulged out or riding more on sidewalls
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[Goldfinger]

keep it close to the maximum it's better for mileage but if you notice wear in just the middle let some air out.

[donut]

IMO, it's like bikes&bowties already mentioned. The 245/75-16's I had on my 73 used to be inflated according to how I was using it. 75-80 psi if loaded or plowing (80psi max), summer or general driving I'd drop back to about 50 psi.

YMMV. @ 50, wear pattern appeared to look good and ride was much better than @75. Mileage didn't change by much if any.

Too much air and the tire will run on a thin strip in the center of the tire, too little and your riding on the edges. Either way, you can do damage to the tire and affect handling of the truck due to changing the contact patch of the tire.
Heat build-up due to improper inflation can also play a factor in the life of the tire.

[Hottrucks]

go old school.....

get some white shoe polish ( you know the one with the little sponge on the top) put somo on the sidewall and tread about an inch or so each way...take it to work or what ever....for every 1/4" the polish is on the side wall add 3 lbs and for every 1/4" of tread showing take out 3 lbs...do it a couple time till you get it just right.....I WILL BUY THE NEXT SET ( ok maybe not but I'm that confident) of tires if you have no other issues in your front end and if those tires dont wear flat and you get the best milage...this works on ALL cars and trucks....the door tags are for MAX load of the vech...but I don't know anyone who has 4,5,6, people and a trunk full all the time...most people I know its just them and a weekly trip to the grocery store


Over or under inflating tire will give better mileage UNTIL the center/outsides are worn then all you have is a 1/2 bald tire...rolling resitance ( tread design and hardness of compound) is the biggest factor on milage ...this is the reason that you see ALOT of big trucks going to Super singles instead of the old style duals...10% less rolling resitance

[tucsonjwt]

Higher tire pressure = quicker tire wear in center, but better gas mileage. Since our trucks don't get good gas mileage regardless of tire pressure, it makes more economic sense to set the tire pressure where it gives the best tire wear. If you are hauling a heavy load or towing, then higher tire pressure is better. Load range D or E tires for my 3/4 ton truck are now $500-$600 minimum for cheap tires, so saving a little on gas does not offset the cost of quickly worn tires. If you drive a lot of highway miles, then high tire pressure might be close to a break even on accelerated tire wear vs. fuel savings.
I keep my BFG load range D commercial tires at 60 lbs. all around. I drive very little and only city miles so it works out OK. I am getting sidewall tire rot much sooner than tread wear over 6 years of tire use in the hot AZ desert.

[Hottrucks]

lets talk tire wear...heres my TRUCK....$1500 for 2 tires but only $200 for an alignment my old tire wore on the inside cutting tire life 10% (read as $150 or 10,000 miles) so you can see that a good alignment is worth it weight also....