Question about tire pressure and why OEM states that it needs to be set at 50 PSI

Ok this question has been on my mind…

In all my years I have had a number of vehicles - and all of them have had P-Metric tires. With that being said, the sticker on the door frame has always called for a cold pressure around 30-35 pounds. Very common, in fact, my tire pressure gauges have the 31-33 PSI area shaded in to “clue” you into what you should look for when checking/adding air.

When checking the tires on these various autos, the max. pressure is always higher than the recommended tire pressure.

My truck, however, states that the cold pressure for the LT tires to be set at 50 PSI, and the max. pressure on the tire is 50 PSI.

So my question is this- why is there no “room” between maximum pressure and the recommended pressure on my truck. I know that some truck tires, such as E rated can be filled with 80 PSI and I also know that load carrying capacity is altered by the pressure of the tire. I did not want to discuss those aspects but rather my question of why the max. pressure and the tire pressure have to be one in the same. I feel that the tire at max pressure does not have any “safe tire pressure wiggle room” like the tires of my other vehicles. This is where my knowledge of tires starts to become foggy.

On a side note, I have had more than one dealership, garage, etc. set my tires at a lower 32-35 pounds and then state that they do that to all tires, regardless of the door sticker. I believe that door tag was put there for a reason and we should follow its information! Other garages have put the recommended 50 PSI in them, letting me believe that not all people in the trade value those recommendations the same! Thanks for any and all advice on this thread.

You’re right that the sticker governs (except if sticker is higher). In your case I wonder if you have the right tires. I had a similar problem. I got tires that were rated a few psi too low for my suburban. My mistake. Check on tirerack if you have the right load rating.

It would be helpful to post details on the vehicle and tires. One thought was you actually have passenger car tires on your light truck. Hard to figure out if those details are omitted…

First, tires have a built in margin on the high end, secondly, I agree that you may not have LT rated tires or tires that are rated too low for your vehicle. Load capacity depends on how much air you can safely put in your tires. If you are running around with no load, 32 lbs may be perfectly acceptable. The idea you must have 50 lbs in an unloaded light pick up is a CYA. It is too inconvenient for mst people to change tire pressure at the drop of a hat.

I think dagosa and other might be right that you don’t have the right tires on your vehicle. As long as the load rating matches, you’re probably fine, but the wrong tires may affect the truck’s ride and handling dynamics. (actually the ride might be better) If you keep these tires through the summer, I don’t think I’d keep them inflated to 50 ‘cold’ for hot weather if this is the max. psi. Sounds like a good recipe for a blowout at highway speeds.

Something fishy here? Is this a standard pickup like a Ford F-150 or a Super Duty like F-250 or F-350? 50 psi on the door sticker seems high for a F-150 sized pickup truck. A Super duty would have much higher load rating on the factory recommended tires and not be maxed out at 50 psi. If the sticker is being read correctly, then the truck is running the wrong tires.

My first set of tires were firestone steeltex LT 245 75 r16. They were OEM and the max pressure on them were 50. I ran them at 45 and got 65,000 out of them and was satisfied. My truck, 2004 Chevy silver ado 1500 ext cab, has a towing package and that is why I believe the door sticker calls for LT tires to be run at 50 Psi. 10,000 miles ago I put on firestone destination a/t tires that have the same max pressure of 50 psi. And while the door calls for 50 I run them at 45 and they are wearing evenly. I don’t really feel a difference when I ran tires at 33-35 in the past (when the garage “lowered” the pressure) and I don’t really worry about ride quality - it’s a pickup truck.

I do not haul anything on a daily basis and I do not tow anything as well.

My concern is this- should I worry at all about the recommended pressure and the max pressure being one in the same ?

These are the recommended tires according to load range.

Even a mid range pickup like the k2500 will run load range E tires for any hauling or towing. Starting pressure is 50-55 unloaded. Fully loaded I ran 75-80. I remember buying tires from Sears. One time I didn’t bother to check in their parking lot and when I got home 30 miles from there the tires were way too hot. Found 32 psi all around. Was I PO’d!! That could have seriously compromised my new tires. The manager was clueless and said what someone already mentioned- we set all tires to that. Moron.

I wouldn’t be worried about running the tires at the sidewall pressure, since it matches the sticker pressure. As said above, there’s a safety margin present.

In my opinion the vast majority of blowouts are caused by underinflated tires overheating and failing, not from overpressure.

I just talked to a guy who raced cars for many years and he agrees with you texases. He said the best way to really check is to have a tool for checking the heat buildup.

I plan on Sticking to running 45 in them all.

I wonder how many people are driving with under inflated tires and how much premature wear is occurring as a result. Not to mention the adverse effects on fuel economy. I know this is an arcane concern of mine but hey, there are now studies that show gas mileage is declining because of obese operators and passengers! Anyway my Suburban is supposed to have 45 pounds in the tires. Recently I had new tires installed and I knew as soon as a pulled out of the shop parking lot they were under inflated. Just felt kind of sloppy. Sure enough, 30psi. As far as heat is concerned I got in the habit of always checking the sidewalls with the palm of my hand after any extended high speed travel. And especially so for the tires of any trailer I was pulling. You know they are good when you can comfortably rest your hand on them and leave it there without immediately imagining frying eggs. I also check the cold tire pressure religiously before hitting the highway (along with oil and coolant levels) and have fortunately never experienced any catastrophic failure in over forty years of driving.

I am going to bump off of london’s comment here. How many people are driving around out there with over-inflated tires? It’s most likely because of the idiotic governmental regulation that requires the “max” pressure be listed on the sidewalls. They should have, at least, put the pressure in code so the general public would not inflate to the max pressure listed on the tire. I’m only mentioning this because a “Wallymart” tire technician argued with me that the best thing to do was to fill the tire to the pressure listed on the sidewall. I let his boss know that he had a dangerous employee working for him.

It would be raelly nice to know the year, make, model, and mileagl of the track, as well as if you’re the original owner. My wild guess with the nonexistant information is that you have the wrong tires.

It is a 2004 Chevy Silverado 1500 5.3 Extended Cab 4x4 Base model (with towing package) with 75000 miles on it. I bought it from my grandfather after he put 1,500 miles on it in 2005 (he decided that he didn’t need it!). He was the original owner. The tires currently on it are Firestone Destination A/Ts LT 265- 75- R16. The original tires on it were Firestone Steeltex 245-75-r16. I am curious as to why you think the tires on it are the wrong ones.

I agree with you guys in that too many people are unaware of the fact that garages and shops do not fill tires correctly. For those who drive pickups, it amazes me that more do not understand P vs. LT metric tires and why they are needed for certain applications (hauling, towing, etc…) It also amazes me to see the number of people driving on tires that I would have long ago retires for deeper tread! Tirerack has done some nice research on the stopping ability of new vs. 4/32 tread vs. 2/32 tread (tread down to the wear bars). The results are eye opening.

Because you said the cold pressure suggested in the owner’s manual was the same as the max pressure on the tire sidewalls. With absolutely no information to go on, that was the logical assumption.

So do you think they are the wrong ones still?

Perhaps. But I’ve seen manufacturer mistakes too. I’d have to see the manual and the tires.

There are high pressure tires and you have them. You should put the 50 PSI in them and not worry. I think you can get away with 45 but I think you should have 50. You can’t tell the difference (much) any way.

I hope everyone now realizes why tire pressures are so confusing.

First, P metric tires are typically inflated in the 26 to 35 psi range.

LT metric tires are in the 40 psi to 80 psi range.

Why the difference? They are designed differently.

Over the road truck tires use 120 psi sometimes. Aircraft tires? I’ve seen over 300 psi. So it all depends on how the tires are designed.

That’s why the vehicle manufacturer is required to put a sticker on the vehicle to tell you what type of tire is needed, the size and the proper inflation pressure.

BTW, people shouldn’t listen to what is done at the race track. That doesn’t apply to street usage. A racecar’s tires only have to last as long as the race - and not years and years and tens of thousands of miles. The whole point of the race is to get there first and that involves sacrificng something in order to do that. On the street, you shouldn’t be treating your tires like that.