Hi Blog World,
I promised you an explanation of Speed Ratings.
The key is that the tire has the capability to do the speed it is associated to. As I put in another post, generally speaking, a tire with a higher speed rating handles better delivering better grip in cornering, accelerating, and braking. A common thought is that someone doesn’t need this. Do you really want to stop slower rate?
I grabbed this chart from our website since it is so complete. Click the chart to see it enlarged.
The most basic way you can think of how these work and how they will mix into different vehicles is nothing more than a equals to or greater than approach =>.
Let’s say we have a vehicle and it has 91S service description.
This means that a tire that has a like speed rating S, in this case, will be perfectly fine for the vehicle. In addition, from the above chart, you can also use speed ratings T, U, H, V, W, Y, (Y), or Z. All these will work with this vehicle. Now, don’t let Z speed rating confuse you with W and Y. W and Y rated tires are Z rated and will often times say ZR along with the W and Z rating.
Likewise for the Load Index part of the Service Description, any value higher than or equal to 91 will suffice.
In short, you can always go to higher load or speed rating, but you shouldn’t go lower.