What tire pressure should I run?

[ksa8907]

Originally Posted by CapriRacer

I guess I have to say it again:

Inflation pressure is just one of many variables when it comes to tire wear - and it isn't the most important. You can get even wear on underinflated tires as well as overinflated tires. You can also get uneven wear on properly inflated tires.

So even wear is NOT an indication that the inflation pressure is where it ought to be. And uneven wear is NOT an indication that the pressure is wrong.

This is starting to sound like there is no black and white answer, which i am glad you bring attention to. We live in a gray world, there are few absolutes.

100psig inflation works well in a semi truck tire, not so well in a passenger car tire.

[Hersbird]

Originally Posted by EcoCivic

Ok, but the recommended pressure is for the average person who just wants a smooth ride. Rhat about people like me who don't care about a "smooth comfortable ride" and just care about stopping distance, handling, tire wear and gas mileage?

Ford actually went so far as to recommend lower than safe operating pressure on the Explorer with the Firestone tires to pass rollover testing and give a "car like ride". Lots of people were killed by this bonehead move. Firestone took a bunch of "heat" for flaws in the tires but the biggest flaw was running low pressure (only 26 psi was the Ford recommendation) which builds tons of heat in rolling resistance and breaks the tire down. Most of the failures happened in the hottest, southern most states.

I wouldn't just take the manufacturers recommendation without some critical thinking on your own behalf.

In the truck/hauling world you must go over the recommendation to allow for Max load rating. Running LT tires at non-LT tire pressures actually gives you a lower load rating than the standard tire if run at the rating on the door sticker.

[ecocruze]

That's all I ever think about when I look at door placard tire pressure. I have always run mine a bit over recommend but since joining this forum I have been pushing max sidewall. Had 51 max sidewall before and when I switched to 44 psi max sidewall I have stayed with 50 psi. Car still remains quieter than old tires and cut mpg loss from going to non LRR tires in half.

[CapriRacer]

Originally Posted by Hersbird

Ford actually went so far as to recommend lower than safe operating pressure on the Explorer with the Firestone tires to pass rollover testing and give a "car like ride". Lots of people were killed by this bonehead move. Firestone took a bunch of "heat" for flaws in the tires but the biggest flaw was running low pressure (only 26 psi was the Ford recommendation) which builds tons of heat in rolling resistance and breaks the tire down. Most of the failures happened in the hottest, southern most states.

I wouldn't just take the manufacturers recommendation without some critical thinking on your own behalf.

In the truck/hauling world you must go over the recommendation to allow for Max load rating. Running LT tires at non-LT tire pressures actually gives you a lower load rating than the standard tire if run at the rating on the door sticker.

I'm going to disagree about the inflation pressure on the Ford Explorers. I've written up my comments on the subject:

Barry's Tire Tech

Bottomline: The placard pressure for the Ford Explorer was adequate to carry the loads specified. There were a number of specific problems with the Firestone tires, that did not exist other brands of tires.

Further, since that incident EVERY vehicle manufacturer has re-examined its tire pressure specifications and as a general rule, the pressure is MORE than the GAWR requires. In other words, even if there was a problem, they fixed it.

[PaulB2]

My VW Passat recommended pressure is 32 PSI, and I run them at 36. I recall trying 38 but the handling was not to my liking so I went back down. The tires have 58,000 miles and I'm still not down to the wear bars; the wear is even too. At 36 I know the ride is a bit harsher, but not enough to deter me. They are the stock Hankooks.

"Everything in moderation"?

[McDesign]

Originally Posted by EcoCivic

I have a 2005 Civic with Kumho Ecowing KH30 tires and I need help deciding what air pressure to run in the tires. Honda recommends 30 PSI. I am currently running 38 PSI cold in all 4 tires, and I am wondering if that is a good pressure. My priorities are safety/handling, long tire life and gas mileage. 38 PSI seems to work very well, but I am concerned about wearing out the center of the tires from too much pressure. What pressure should I run? Thanks!

I've run 50 psi in my '91 Accord with 195/60-15s for five years now. Seems fine.

[slowmover]

I use the door placard range. Its higher than the Load & Pressure Table as those are dead minimums and test for pressure rise (CapriRacer, tire engineer who has posted here).

This is after weighing the vehicle on a segmented scale, and then all four corners.

First set of tires on this one ton lasted to 6/32's at 120,000-miles. At that adjusted minimum.

Safety trumps a couple of dollars. A tire inflated very much past what is needed is compromising the contact patch. Tune the suspension for better vehicle response, not the tire pressure.

Decreased tire life, suspension and steering component life plus various other ALONE should discourage this practice.

Tire quality, design, and correct tread for use are what matter.

And external heat measurement doesn't work. Another engineer who blogs on RV tire safety can take you through that problem.

.

[stefanv]

Turns out this is all moot for me. Maximum pressure stamped on the sidewalls of my tires is 35psi, which is already what I run them at (door sticker recommends 28 front and 26 rear). I was hoping to try higher, but won't with these tires.

[Hersbird]

Originally Posted by CapriRacer

I'm going to disagree about the inflation pressure on the Ford Explorers. I've written up my comments on the subject:

Barry's Tire Tech

Bottomline: The placard pressure for the Ford Explorer was adequate to carry the loads specified. There were a number of specific problems with the Firestone tires, that did not exist other brands of tires.

Further, since that incident EVERY vehicle manufacturer has re-examined its tire pressure specifications and as a general rule, the pressure is MORE than the GAWR requires. In other words, even if there was a problem, they fixed it.

Right, they fixed it by changing the recommended pressure to 30spi. It was 35 on the Ranger which didn't have a problem, it was higher on other cars/suv that used the same firestone tires that didn't have any issues. It occurred mostly on Explorers in hot southernmost states. There may have been a flaw there but it was exposed by heat from low pressure. Run a more normal pressure and there was no problem with the tires.

[McDesign]

Originally Posted by stefanv

Turns out this is all moot for me. Maximum pressure stamped on the sidewalls of my tires is 35psi, which is already what I run them at (door sticker recommends 28 front and 26 rear). I was hoping to try higher, but won't with these tires.

Ah, try it - it's a light car; "they all say max 35 psi".

And yes, I am a mechanical engineer.