Tires: please help!, Tire Size and Pressure

Question
I have a 2002 Chevy Tahoe. I have been looking at new tires. My Tahoe currently has 255/70R16 on it now. Wal-Mart told me that wasn't even the right size for my truck! Sears told me it didn't matter! Does it matter? What is the normal size for my Tahoe?

Answer
Brandi,

On every vehicle sold in the US, there is a sticker commonly - called the vehicle 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.

If I remember correctly, on GM trucks, the placard is on the doorpost.  That is the proper size tire for your vehicle.