Tires: Buick Lesabre tire inflation, tire placard, inflation pressure

Question
Our 1992 Buick Lesabre has two front tires that look partially flat, even though the mechanic said they are at the recommended 30 pound pressure. Is this normal because the car is so heavy?

Answer
Dee,

On every vehicle sold in the US - and I understand this is a worldwide practice as well - there is a sticker – commonly called the tire placard - that lists the original tire size and the proper pressure for that size.  The placard is usually located on a doorpost or in the glove box – but sometimes it is located in the trunk or on the fuel filler door.

BTW, it doesn't matter who makes the tire or what pressure is listed on the tire's sidewall, if the tire size is the same as the placard, then the pressure listed on placard is also appropriate.

If you are using a tire size that is different than what is listed on the placard, then the pressure has to be recalculated.  The calculation is not difficult, but it requires tire load tables which are not allowed to be published in the Internet because of copyright laws.  However, I have a copy and would be glad to do the calculation, but the starting point is the vehicle placard: Tire size and inflation pressure.  I will also need to know the new tire size.

In your particular case, I'm guessing the front tires look more deflected than the rears because the engine 9 a lot of weight) is up there and your trunk is empty.  If you were to load your trunk up, the tires would look the same.