Ultra High Performance tires all have A or AA traction and A temperature ratings but come in a pretty wide range of treadwear ratings. Can you use the treadwear rating as a "stickiness" measure?
The Sumitomo HTR Z has a treadwear rating of 160 and the Fuzion Zri has a rating of 320. The Dunlop Direzza DZ101 has a rating 300. Can you use the treadwear rating to make a decision on a tire for autocross? Would the Sumitomo be the better tire?
I don't know, therefore I ask.
You can only use the treadwear as a stickiness measure within the same brand, and then it's not an exact relationship.
It's kinda like tire sizes, they are only a guideline, not a real size.
On 265/35 x 18" I have found as much as a 2" difference in widths between brands and models.
I am not sure why we have either if they aren't going to mean anything.
Even within the same brand treadwear is somewhat meaningless. Especially if that brand is Bridgestone. The RE92 (known as one of the worst tires ever) has a treadwear of 160, while the RE01R (known as one of the best autox tires ever) has a treadwear of 180.
I certainly wouldn't use it to compare the tires you have listed. Unfortunately, not many people/magazines take the time to compare street tires that are not competitors in the ST classes.
Here's a brief explaination of threadwear:
~This is a rating of the tread's durability, as tested against an industry standard. The reference number is 100 so a tire with a treadwear rating of 180 has an 80 percent longer predicted tread life while a rating of 80 means a predicted tread life only 80 percent as long as the industry standard. And there is a newer standard that goes from 20 to 620.In either case,the higher the number, the longer a tire's useable tread life.~
...but it agree, it doesn't seem consistent between tires and their "stickieness" vs wear.
I ran Kumho Advans (40 TW) and Yoko A032Rs (50 TW) they didn't seem to stick more than the Toyo RA-1s (100 TW) that I'm running now on my vintage race Sprite. Wear seemed about equal.
I also have bigger RA-1s on my NASA PTF Escort and they have a 40 TW, but seem to wear pretty well.
I just ordered a new set of Toyo R888s (the RA-1 replacement). They have a TW of 100. I guess I'll see how they work.