Tires: tire sizes, tire failure, tire specifications

Question
My Tahoe XLT tire specifications call for 265/70R/16.  I would like to replace with 255/70R/16. Currently running Firestones will replace with Michelin Coss Terains.

The load on 255/70R/16 is rated a hundred pounds less than 265/70R/16. Also the tire revolution per mile is greater on the 255's.

Is this a major safety issue?

Thanks, Earl

Answer
Earl,

This is indeed a safety issue.

I prefer to think of this sort of thing as risk - which is the inverse of safety (simply because most of us have trouble with the concept of "less safe" or "more safe".)

By decreasing the load carrying capacity of the tire, you are increasing the risk of a load related tire failure - and any sort of tire failure where the load on the tire is a factor (which is pretty much all of them.)  

This is one of the lessons that came out of the Ford / Firestone situation a few years back.  To their credit, the vehicle manufacturers recognized this and took the steps to increase the load carrying capacity of their tires.  (This wasn't the first time they did this, and it likely won't be the last.)