Tires: 2005 Cadillac STS, tire placard, tire guides

Question
My front tires are a different size from the back tires.  What was the original tire sizes issued with this vehicle both front and back?

Answer
Nancy,

On every vehicle sold in the US - and I understand this is a worldwide practice as well - there is a sticker – commonly called the vehicle 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.

According to Tire Guides, some versions of your vehicle came with different tire sizes front to back - and the wheels are different, too!  So you really need to check the vehicle tire placard.

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.