Why different tire brands for different sizes?
#1
Mach 1 Member
![](https://themustangsource.com/forums/images/rank.gif)
![](https://themustangsource.com/forums/images/rank.gif)
Thread Starter
Join Date: May 7, 2007
Location: New England
Posts: 616
Likes: 0
Received 0 Likes
on
0 Posts
Why different tire brands for different sizes?
I am just curious why the Mustang has Pirelli's for 17" wheels, and BFGoodrich for 18" wheels. On a side not (sorry I am in a tire state of mind at the moment) what do the numbers (such as 300A A a vs. 400AA A) next to UTQG represent, treadwear?
Last edited by jmanpatsfan; 5/25/08 at 05:17 PM.
#2
AKA 1 BULLITT------------ Legacy TMS Member
![](https://themustangsource.com/forums/images/rank.gif)
![](https://themustangsource.com/forums/images/rank.gif)
![](https://themustangsource.com/forums/images/rank.gif)
![](https://themustangsource.com/forums/images/rank.gif)
![](https://themustangsource.com/forums/images/rank.gif)
Price and rating.
#3
Mach 1 Member
![](https://themustangsource.com/forums/images/rank.gif)
![](https://themustangsource.com/forums/images/rank.gif)
Join Date: October 22, 2004
Location: Niantic CT
Posts: 819
Likes: 0
Received 0 Likes
on
0 Posts
![Smile](https://themustangsource.com/forums/images/smilies/smile.gif)
#5
Mach 1 Member
![](https://themustangsource.com/forums/images/rank.gif)
![](https://themustangsource.com/forums/images/rank.gif)
Join Date: July 16, 2004
Location: Greenfield In.
Posts: 851
Likes: 0
Received 0 Likes
on
0 Posts
This seems to be correct! Thanks for the info.
Treadwear Grade Number
The treadwear grade describes how long the tire manufacturer expects the tire to last. A Course Monitoring Tire (the standard tire that a test tire will be compared to) has a rating of "100". If a manufacturer assigns a treadwear rating of 200 to a new tire, they are indicating that they expect the new tire to have a useful lifespan that is 200% of the life of a Course Monitoring Tire.
[edit] Limitations
The DOT does not test tires. It depends on manufacturers to test their own tires and report the results. Unfortunately, this system has made treadwear ratings far less useful than the DOT had originally intended because tire manufacturers are able to use the treadwear grade as a marketing tool.
It is legal and permissible for a manufacturer to give their tire a 240 rating when their competitor's equivalent tire has a 220 rating; thus creating the false impression that the 240 tire is a better purchase because it will last longer. This tendency to inflate treadwear numbers has become so common that some manufacturers may report that ALL their tires have above average treadwear grades. Some are taking normal tires and reporting a treadwear of 600 or more, or giving a 220 rating to maximum performance tires with a reputation for poor tire life (e.g. the Goodyear Eagle F1 Supercar EMT).
Treadwear Grade Number
The treadwear grade describes how long the tire manufacturer expects the tire to last. A Course Monitoring Tire (the standard tire that a test tire will be compared to) has a rating of "100". If a manufacturer assigns a treadwear rating of 200 to a new tire, they are indicating that they expect the new tire to have a useful lifespan that is 200% of the life of a Course Monitoring Tire.
[edit] Limitations
The DOT does not test tires. It depends on manufacturers to test their own tires and report the results. Unfortunately, this system has made treadwear ratings far less useful than the DOT had originally intended because tire manufacturers are able to use the treadwear grade as a marketing tool.
It is legal and permissible for a manufacturer to give their tire a 240 rating when their competitor's equivalent tire has a 220 rating; thus creating the false impression that the 240 tire is a better purchase because it will last longer. This tendency to inflate treadwear numbers has become so common that some manufacturers may report that ALL their tires have above average treadwear grades. Some are taking normal tires and reporting a treadwear of 600 or more, or giving a 220 rating to maximum performance tires with a reputation for poor tire life (e.g. the Goodyear Eagle F1 Supercar EMT).
Thread
Thread Starter
Forum
Replies
Last Post