Tires: Original tires for Chevy Silverado 1500 & swapping tire sizes, chevy silverado, 2004 chevy silverado

Question
Hi Barry,

I drive a 2004 Chevy Silverado C1500.  I bought it used.  It’s currently running on P255/70/R16 109S tires.  I have two questions:

1) Everything I can find indicates that the original equipment tires should be 235/75/R16, but the sticker on the driver’s door pillar states that the tires should, in fact, be 255/70/R16 (what it’s running).  Can you shed any light on why this disagreement exists, and whether I should be concerned by it?  What is the “real” original equipment tire size?

2) Given this uncertainty over the correct tire size, can I use P245/75/R16 109S tires on the truck safely?  I’m aware that running taller tires will cause the speedometer to read too low, but the speedometer already reads ~2mph higher than the speed at which the vehicle is traveling (according to police radar speed signs) so that suggests to me that using slightly taller tires should cause my speedometer to become more accurate.  Is my thinking correct?  Are there any other concerns I should be aware of?

Thank you!
Chris

Answer
Chris,

1)  Unfortunately, trucks come in some many configurations, it is easy to get lost as to what tire size a particular truck came with.  The only truly reliable source is the vehicle tire placard.

2)  A P245/75R16 is the functional equivalent of a P255/70R16.  Sizingwise, they can be interchanged.  Just be aware that some tire properties are tied more to the way they were designed and not the size.