Tires: Speed rated tires, passenger car tires, light truck tires

Question
Barry,

I have read mountains of info on speed rated tires and understand the concept.
I know that light truck tires are not speed rated.
My situation is, I like to drive fast on a very remote paved road in Alberta.
Can you suggest a tire for a 2005 GMC 1500hd 4 door crew cab 4x4. It has quadrasteer as well.
I just want to know if there is a tire manufactured that I could purchase that will fit on a 16 inch rim and be as good as one that had the speed rating indicated on it.

I work overseas in Yemen and could ship tires home to Alberta Canada from Europe if they could be purchased there.

Thank You,
Randy


Answer
Randy,

I think you will find that most light truck tires are speed rating.  Certainly the tires supplied to GM are.

However, you will find that most light truck tires have low speed ratings compared to passenger car tires.  This is due to the nature of the tire in the 2 categories.

Typically, passenger car tires are minimally speed rated at S - which is fairly easy to achieve by using conventional tire design techniques.  T and higher speed rating usually require some additional reinforcement to achieve those speed ratings.

A light truck tires can not be designed using conventional design techniques to achieve more than a Q speed rating - and in some cases an R.  Speed ratings higher than that are achievable using the same design techniques as passenger car tires, but then the speed ratings generally stop at S.

To find the speed rating of a tire, you need to find the "Service Description".  It will be in the form of a number and a letter, like this - 116Q - where the numbers are the load index and the letter is the speed rating.  For light truck tires, it is customary to have to load indices as light truck tires are sometimes "dualled" - 2 tires mounted side to side on the same corner - 4 to an axle.  In this case the Service Description will look like this - "116/113Q".

Do a little searching and I think you will find a tire with a suitable speed rating.

BTW, it is more likely you will find these tires on the North American side of the ocean as Europe uses smaller pickup trucks and vans than the US and Canada.