Tires: tires, passenger car tires, load index

Question
What dose the load index  for a tire mean, and where can I found the information. I am looking for tires and all the warnings say "will not install tires with a load index below that of your vehicle's Original Equipment (OE) tires."

Answer
Doug,

Load Index is a measure of a tire's load carrying capacity.  Obviously, it would be going the wrong direction to install a tire with a LOWER load carrying capacity as that increases the risk of a load related failure - which sometimes has tragic results.

When you look at a tire size, it will look something like this:  P225/60R16.  - BUT - the complete description includes a number and a letter after the tire size - like this:  P225/60R16 97H - where the 97 is the Load Index and the H is the speed rating.

The quirk in this is that for Passenger Car tires, the size pretty much determines the load carrying capacity - and the differences in Load Index between tires of the same size has more to do with the different standardizing organizations and the way they calculate Load Index than it does with actual construction of the tire.  For practical purposes, the constructions are the same.  The except to that is the difference between Standard Load (SL# and Extra Load #XL), where there IS a difference in load carrying capacity.

However, this is not true for LT type tires, which come in Load Ranges.  It is important to chose the proper Load Range for LT type tires.