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Proper Tire Inflation

I recently purchased my 16 year old daughter a 2001 Oldsmobile Alero. The tires on the car are Continental ContiExtremeContact tires. The tires were purchased from Discount Tire Co. before I purchased the car.

My question is Discount Tire is recommending inflating the tires to 30 psi, but on the tires it says that the maximum pressure can be 44 psi. I have always heard that you should keep your tires fully inflated for better gas mileage and proper wear. The guys at Discount tire tell me that while the maximum pressure listed is 44, the tires will wear better at 30 psi. Please let me know what is best for the tires.

Look on the door pillar for a manufacturer’s label. The proper pressure for the tires will be listed there. The tire place is right - It goes by car, not by tire. You can run them a little firmer as long as you don’t exceed that 44psi cold.

We get this question at least once a month. The owner’s manual and the number on the door post or glove box lid is the proper inflation pressure FOR YOUR CAR.

The number stamped on the tire is the maximum safe pressure this tire can be inflated to; it has nothing to do with your car’s requirement.

With 44psi the car will ride rough, and the tire may wear excessively in the center. However, if this car was raced, the racing driver may insist on having 44psi to keep the tire from overheating at high speed and cornering.

So, stick to the what is in the manual or stamped on the car, and it is likely close to 30psi or a little more. The Discount Tire guys are closer to the truth than the number stamped on the tire.

Check the manufacturer’s recommended pressure, found on a placard on the door frame. It is probably closer to 30 than the 44 max on the tire. The maximum tire pressure on the tire is exactly that. The manufacturer’s recommendation should provide a reasonable ride and decent tire wear. Some folks overinflate a couple of pounds in pursuit of better tire wear, but start with the manufacturer’s recommendation first.

You’ve heard wrong. Overinflating the tires that much will cause improper tire wear and make the car ride like a truck. More important, it will reduce handling capabilities, especially in emergency maneuvers. Follow the label on the door jamb or the owner’s manual (assuming these tires are the same size as the OEM ones).

“Fully inflated” means to the pressure recommended by the manufacturer for your specific car. That’s on the door jam.

“Maximum pressure” as on the tire sidewall is the maximum pressure the tire will withstand without danger of exploding…yes, exploding. There is a federal test standard that the tires are tested to.

Go by the door jam placard.

If the door placard is missing, this site recommends 30 psi for the Alero.

My personal preference is to run 2 or 3 PSI higher than the placard for crisper steering response. My 2010 Cobalt (similar size and weight) with Continental Touring Contact AS tires (195/60R15, Max Pressure 44 psi) recommends 33 psi. At 44 psi the ride would be unbearable.

There’s good info on tire pressure and care at Tire Rack.

Ed B.

Use the recommended tire inflation pressure listed on the vehicle. I have always used 32 psi on normal passenger cars and trucks. Never had a problem with my tires or their wear and I always get good fuel economy. The problem with using 44psi is that tire pressure increases as the tire heats up. It might not be bad in the winter but just imagine traveling down the interstate in Arizona when the temperature is over 100 degrees.

The “MAX COLD INFLATION” pressure on the tire allows for the fact that it will heat up and the hot pressure will be higher. That’s not the problem.

The two real problems are:

  1. There will be less contact area between the tire and the road than the car manufacturer counted on if you inflate to a higher pressure than stated on the door placard.
  2. The sidewalls of the tires will flex less than the car manufacturer counted on if you inflate to a higher pressure than stated on the door placard.
    This all means that your handling and ride comfort will be affected. How much is hard to say, except for case by case.

My experiences have been good using the pressure(s) listed on the door placard.
If the placard gives a pressure higher than the one stamped on the side of the tires, then you bought the wrong tires for your car.

The number on the tyre is NOT a recommendation, it is a maximum for that tyre. The manufacturer had no idea what car that tyre was going to end up on, so they can not judge what pressure would be correct for your car. That is why it says maximum.

The question that you pose is a fair one and will continue to be asked until tire mfrs. put an additional statement on tire sidewalls that could read as follows: “Maximum inflation pressure is for tire installation on wheel. See label on vehicle door jamb or door edge for normal cold inflation pressure.”

The present tire sidewall labeling regarding pressure is misleading and has been this way for years. I, for one, wonder why this continues. Someone in a place of authority, likely governmental, is sleeping at their desk.

In addition to tire tread wear consideration, I would be concerned with the possibility of reduced traction at the maximum inflation pressure.

In my opinion there is a safety factor that comes into play when the maximum inflation pressure as per the sidewall is used in error. Inflation pressure will increase when a bump is encountered.

I know what you are saying and have the same labeling on my and my wife’s Alero tires. We run them at 90% of the sidewall max figures - 40psi - with no problems and excellent tire wear and traction. And, for my Summer (May thru Oct) performance tires for my Alero, which sport a sidewall max of 51psi, I run them at 45 to 46 psi with excellect results.

WhaWho said: “…The present tire sidewall labeling regarding pressure is misleading and has been this way for years. I, for one, wonder why this continues…”

I know the answer to this one. Because the regulators - the same one’s you accused of sleeping - INSISTED that there be no change. It was proposed - and denied - to remove the maximum and replace it with a statement similar to what is being discussed - and for the exact reason you mentioned - confusion.

BTW, the pressure increase caused by a bump is tiny - less than a psi! It is commonly held myth that tires will explode if the sidewall maximum is exceeded - well it MIGHT if you exceed it by a factor of 2!

Oh and Galaxy’s 90% value (see below) is as wrongheaded as can be. The whole issue about what gets put on the sidewall as a maximum pressure is pretty complex and would take longer to explore than this thread allows.