What is a the proper PSI for a tire that says 44 PSI max?
The door plate says 30 PSI. The tires are not factory tires. My mechanic thinks I should go by the door plate I think I should go by the tire.
The door plate says 30 PSI. The tires are not factory tires. My mechanic thinks I should go by the door plate I think I should go by the tire.
hello
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you should probably go somewhere in between. the 44 is max pressure for a hot day after the car has been run a while. the 30 lbs is for comfort but is bad for fuel economy. a few more pounds will improve handling and fuel economy. typically 35 lbs is a good compromise.
Naughtums
All modern Standard Load range passenger tires, including the tires that originally came on your car have this molded on the sidewall:
"Max Load ____kg (___lb) @ 300kpa (44 psi) MAX PRESS."
Does that sound like a recommendation for how much air to put in that tire when mounted on your specific vehicle? Or does that just tell you how much wieght the tire can carry when it is fully inflated?
There is however, more printing on the tire that it seems nobody EVER bothers to read. It says:
"SAFETY WARNING: SERIOUS INJURY OR DEATH MAY RESULT FROM: Tire failue due to underinflation / overloading - follow owners manual or tire placard in the vehicle."
Now, does that sound like a recommendation? And what is it telling you to do? Go by what it says on the door.
Why?
Tire inflation pressure is determined by tire size. Any tire of the same size as originally fitted to your vehicle, no matter what company made it or what model it is has the exact same inflation requirements as the tires that came on your car from the factory. So, unless you changed tire sizes 30 psi is still the optimum inflation pressure to run no matter what kind of tire it is.
The folks who made your tires probably have a web site. Go there. They will have something on their site that tells you the same thing - follow the Tire Load and Inflation recommendations on the door tag.
If you did change tire sizes that is the subject of a different discussion. That gets a bit more complicated.
Tires are what I do for a living so unlike some of the other people who are making up BS theories this is 100% industry approved information you can take to the bank.
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Convert 300 Kpa To Psi
bobweb
I've got an idea! Let's split the difference between the max tire pressure and the vehicle manufacturer's recommended COLD tire inflation pressures. Let's see, if we add 30 psi to 44 psi and divide by 2, we get 74 psi divided by 2 or 37 psi. THAT's what I'd inflate those tires to. Make sure the tires are cold. By the way, that's what I inflate all my car tires to, about 36 psi (cold).
Eric F
going by the door plate is the SAFETY answer for the mechanic.
You are correct they are not factory tires.
Here's the fact: when tires get HOT, the air inside expands up to 6pounds. this also depends on your tire's temperature rating. a rating of A will allow the air inside to disperse/cool down faster than a B or C.
Most tires have an A or B
My formula is this. Whatever the TIRE says, in your case, 44psi, subtract 6 pounds of air. so in the hot weather, you'll run at 38psi.
in the winter, you'll run at 40psi. Does 2psi make a difference? Barely noticable, varying on your car and how well you know it.
If you get servicing done, assume they will deflate the tire to 30psi because it's "safe". 30psi in a 44psi tires will give sloppy handling and will increase tire wear, don't bother arguing, just adjust the pressure back for yourself.
IF you tires are 35 or 36psi, my formula differs.. I now run at 32psi for winter and usually leave it in the summer as well.
Will they expand past 36psi? Sure.. it won't hurt anything.
If it's like super hot and I'm going on a trip, I might drop it down to 30psi.
Of course, always make pressure adjustments when the tires are COLD, all shops make them at that moment, hot or cold, so they'll usually be wrong and you can't argue with them because they don't know, they're repeating what they're trained to do.
Just make your own adjustments.
I got into it with a guy from walmart (you can't beat their prices on tires and $5 for 1 time mount & balance.. ). my taurus states 35psi on the placard for tire psi, I'm impressed by that actually. the walmart guy put 30 and said the 35 was to much for a 44psi max tire. So I said, just do what you're trained to do, I'll take care of it later. so I went 2 blocks to the gas station and aired up to 38psi.
I have never had obscure tire/tread wear and have always had a great ride/handling combination, and have never (knock on wood) had a blow out. I do however seem to have forgotten to take the magnet out because I pickup a lot of nails.