Just dont get it - Tire pressure

What width are your wheels? If they are narrow, it will cause the tire to bow across the tread area causing the center to make more contact with the ground. I have 315/70/17 on 17x8 wheels on my Silverado and they look similar to yours. I run around 33-35 lbs. and as long as you rotate front to rear every 5 to 10K miles they should wear evenly. 40 lbs sounds pretty high unless your doing serious weight carrying or looking for extra mpg.

 

Pressure advice is to give the tire a deflection that wont overheat them, when driving the speed the maximum load of tire os calculated for
The pressure/ loadcapacity- list take care that for every pressure, the weight on tire is given, that gives this deflection.

Its a bit more complicated, but in short , this is the only thing the tire- and car- makers care about.

If an LT-tire E-load Needs a bit more pressure for the same load, to give it the same deflection as a SL P-tire, because the larger overgoing curve from unloaded radius to flat on the ground.
But even your P-tires could carry about the complete gross axle weight rating, and normal use weigt is already lower than that.
Roughly you can say that the OEM P-tires could do with half the reference-pressure wich is 35 psi for up to 160km/99m/h.
All educated quessing. Now on mobile phone, so to be continued.

 

True, was thinking putting less weight on the rubber would cause it to wear a little slower though, due to the thickness. But I'm just guessing. If your experience has been otherwise, I'll take your word for it!

 

I have always heard that E rated tires take more psi. But what you are saying makes total sense. I have learned a lot in the past week. And great advice about trusting the chalk test...and using the same gauge. Thanks!

 

Theoretically, an E tire will squirm less on the road, and squirming does wear rubber. In actual fact though, tire wear seems to follow driving habits more than load rating, at least for me

 

agree with this. it's also one of the reasons i use E's on my Tacoma. for the driveability of E tires, which is not for everyone on a 4500lb vehicle. especially 265/65's... they're kinda like driving on little rocks.

 

They sure are. The ride is slightly less terrible at 32psi, I've gotten used to it. I LOVE these tires tho. I live in Philly and have a job that requires me to get to work even when it snows 3 feet. Never had a problem since I put these on. Wet traction is outstanding too for such an aggressive tire.

 

When bad information gets repeated enough, it becomes gospel. A lot of misinformation got rolling after the huge Firestone / Ford debacle. Now everyone errs way to the high pressure side to protect their butt from lawsuits. Every time I take my tires in for rotation, they come back hard as a rock. The shop tells me they are required to do that. The tire industry loves it because it wears out tires. Nobody seems to be competent enough anymore to simply take responsibility for their tire pressure. Years ago, EVERYONE that drove knew that you needed more pressure for long road trips, or hauling loads. With bias ply tires there was much less room for error. Now tires are so safe, and people so stupid, that the best advice is just to run them over-inflated all the time. For those who have forgotten, the Firestone / Ford deal is the reason we have TPMS now too.

 

Door sticker regardless of tire type is about where you need to be. Might even be less for an E rated tire. I had E rated falkens and they damn near held the truck up nicely with 10 psi.

OP - chalk test definitely over inflated.

 

I love the way high profile tires like the 255/85-16 drive with E rating. A C rated tire would roll so badly during cornering, in that size, that it would be unsafe. The E's track so well, and steer much more precisely. With a lower sidewall it wouldn't matter as much.

 

yeah the 265/65-17 ST Maxx are like the single most important part of my whole truck package. i modded the suspension around those tires in that size, literally. it's nice knowing i've found my tires for life and never have to think about it again!

so true. when i got my ST Maxx mounted on the Tacoma they came back at 48psi all around. i'm surprised i still have teeth after that drive home.

on the way to work today my readout said 25F, 22R, and they warm up to about 28/25 in the first 3-4 miles. perfect drive, great handling, and can carry a good load at that pressure with this particular tire size, but i would bump up the pressures if i had anything over say 500lbs on a regular basis.

it's also true that, when the weather is back to normal warm here, i'll be shooting for 30F & 27R when fully warmed up. that's the golden zone for my truck, given that i ride light.

 

I used to just do the math right and call it good. Was around 35psi IIRC.

Alignment guy two weeks ago set them all to 60! (BFG AT 265/75R16 e-rated)

Been running them like that since to see if I get better gas mileage but I don't like how harsh it feels

 

You know, My TPMS reads exactly 5 PSI lower than my precision gauge. Have you found that to be true? I'm thinking they offset the TPMS, just like they do the speedometer to cover their butt.

 

You will certainly get better gas mileage, but every other aspect of your tire performance will suffer

 

actually, no. i have a Longacre analog gauge, an expensive one (that alone may not make it accurate i'm aware) and it's spot on with my TPMS readouts. which has kinda surprised me.

 

I've got these same tires and have been running 40psi cold in them for the 30k they've been on the truck. Still have plenty of tread left and are wearing well. I just recently went down to 35, and have no complaints.

 

I run around 35 all the time.

 

Man, what great discussion! I have taken so much away from this. Thanks guys!

 

The sticker in the door jamb is printed with some assumptions that may not apply to everyone. My Tacoma weighs 6000 pounds before I put a load in it or a trailer on it. With my particular tires, at the weight I regularly have in/ on it, 40 psi is the sweet spot. With a heavy trailer, I add 5 pounds to the rear and a few pounds to the air bags too.

 

what are your particular tires, if i may ask? and are they E range?