AboutBarry Smith Expertise I have over 30 years experience in the design, manufacturing, and
testing of tires. I have served as the technical advisor to the "800"
number. I have authored or co-authored many publications - usually
without credit. I can answer almost any technical question, but
please don`t ask me to compare brands. I probably have prejudices because of
my work experience.
Experience Member SAE (Society of Automotive
Engineers)
Member Tire Society (Tire Technical Organization)
SCCA Regional Competiton License holder
Authored many training manuals on tires, their care and use.
Expert: Barry Smith Date: 6/17/2008 Subject: tire load rating vs axle rating
Question Is there a relationship between the tire load rating and the axle rating?
Answer Leslie,
Yes. The simple answer is: The load rating of the tire at the specified pressure must be larger than the GAWR (Gross Axle Weight Rating).
This is a complex issue and how the tire rating is selected based on the GAWR is one of those things that every vehicle manufacturer has, but doesn't publish. However, it is good engineering practice for the tire's capacity to be underutilized - and that is one of the lessons learned from the FORD / Firestone situation a few years back.
But the issue of tire rating vs GAWR is so complex, that to make it simple, there is a sticker the listed the original tire size and the proper pressure for that size - and the GAWR - and with that information, you don't need to know how this works. Either use the same size, or a tire with the same or larger capacity.
But be careful. There are still some pitfalls in changing tire size and they are too numerous to put in this simple Q & A format.
