Tire question

[tcc11tcc]

I just got new tires and they state inflate to 44 PSI. Why did the dealer only put 32 PSI in them? I believe that is what it says to do on the door but these are different tires than what came on them new. For proper wear and towing, do I want the Max PSI?

[CapriRacer]

Just an FYI:

Evenness of tire wear - that is whether the tire wears in the center or the shoulders - is only slightly related to inflation pressure. Put anther way, inflation pressure has a small effect - other things have a much larger affect than inflation pressure.

There has been a trend for pickup truck manufacturers to go to larger than the minimum size tires - and inflate them so. This is because of the Ford/Firestone situation a few years ago. As a result, there is pressure (pun intended) on tire manufacturers to adjust their tires so they wear more evenly at those higher pressures. I suspect enough time has gone by that the latest offerings have been adjusted.

So I don't buy using the load tables by themselves in order to maximize tire wear. I don't like the idea of running tires at the minimum inflation pressure needed.

[pitch]

I replaced my p rated with LT's. Store manager told me when I paid the bill that they could only inflate to the door sticker. Whether by law or store policy I don't know. He then pulled out the air hose and gauge handed it to me and told me do as I wished.

[Campfire_Time]

tcc11tcc wrote:
I suppose this means P rated, P275/60R20

So you fill back ones to 40ish when towing and leave front at 32?

For some reason I thought if you didn't have the tires inflated to where they were suppose to be, they wouldn't wear correctly?

I always inflate my boat and campers tires to what they list as Max PSI because I was told to do that.

Not very mechanical....can you tell 🙂

My door sticker says 30 in front, 35 in back. My Firestone Destination LEs are great tires but are softer than other tires I've owned. I tend to keep 2-3 psi extra in them at all times. They seem to wear much better. For towing I put 5 psi extra all the way around. 35psi in front, 40 in back.

Trailer tires are always aired up to their max psi listed on the sidewall. Even my HTT manual tells me to do that. Vehicles are an entirely different matter. Weight changes how they behave. So yes, in theory, running at psis outside of the recommended can produce abnormal wear. Its a matter of experimenting a bit.

[45Ricochet]

Generally the door post is correct. If you scale your vehicle and know the weights of each wheel you can look up load index charts that most tire manufacturers have on their web sites. Example

[tcc11tcc]

I suppose this means P rated, P275/60R20

So you fill back ones to 40ish when towing and leave front at 32?

For some reason I thought if you didn't have the tires inflated to where they were suppose to be, they wouldn't wear correctly?

I always inflate my boat and campers tires to what they list as Max PSI because I was told to do that.

Not very mechanical....can you tell 🙂

[skipnchar]

The information on the door post gives the proper pressure to enable handling the maximum load the vehicle can carry (GVWR) when using the OEM tires. The NEW tires are apparently in the same class (passenger car tires) so would inflate to the same pressure.

I would READ the part where the tires says what the inflation pressure should be because that makes no sense at all. Tires are NEVER advising what the proper pressure is, they only state what the MAXIMUM pressure they can handle is.

[Campfire_Time]

If they are P rated tires, generally you fill them according to the door sticker for day to day driving. When you tow, put more air in them. Its makes a world of difference towing. I've been running mine at 40psi in the back.

Keep in mind that tires are made to fit a variety of applications. The tire manufacturer has no idea what the handling characteristics of the vehicle are. The vehicle manufacturer does. Unless you deviate from the OEM specs on tire size, follow the door PSI recommendations for day to day driving.

[rhagfo]

Not unless they have a max load on them.
Sounds like P rated tires, when towing I would bring the rears up to close to max, depending on the loading of the rear axle.
My "E" rated tire state max 80 psi, my rear axles only has 5,200# on it when loaded, tires (pair) are rated for 6,830#, so I run between 70 and 75 psi.

[Norskeman]

When the vehicle is loaded inflate to the pressure stated on the drivers door. The 44 psi is probably the max pressure the tire is rated for. Running at 32 psi improves the ride but limits the load capability of the tires. Don't assume that the person who installed the tires is an expert at tire inflation.

I had a Chevy mechanic put 12 quarts in my Duramax when it only takes 10 quarts - had to drain 2 quarts out - luckily I looked at the service slip and saw that he put in 12 quarts of oil.