Tires: Tire size, doorpost, fuel filler

Question
What will happen if I put P255/70R/16 on a 95Chevy 3/4 ton truck?  It has P265/70R16 on it now.

Answer
LeaAnna,

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

My book say a 1995 Chevy 3/4 tons came with at least an LT225/75R16.  This gets into an area I'm normally opposed to: Switch between LT metric and P metric tires.

But to be more specific I need to know what the vehicle placard says.