Quote:
Originally Posted by freebeard
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Allow me to give everyone a short cut:
Pretty much EVERY tire uses silica nowadays. It's old technology. The question is, how can you tell what the RR level is compared to the tire's grip and treadwear?
Unfortunately, you can't. Grip and treadwear are delineated by the UTQG rating - required for all P type tires (except for winter tires!), but RR is more complex and doesn't lend itself to simple testing/labeling. It varies by tire size - even for tires built exactly the same. HOWEVER, RR varies more between make/models than it does for size, further complicating the issue.
This means that trying to gain an improved RR by changing tire size yields small changes, where changing make/model yield larger changes.
A proposal to change the UTQG rating system to include RR has stalled. I don't know what the current proposal is (it was announced, but not published!), but a previous proposal ran afoul of the problem is tire size and how to label.