ok, i know what all the symbols stand for in it, but im wondering exactly what the letters for temperature stand for?

example, Azenis RT-215 is a 200 AA tire.

my goodyears(185/70 13) are 280 AB. what does the b stand for?


oh, and i DID search

 

The tire engineer LOVES when you ask questions like this

Government testing requires that all tire companies stamp their tires with this information. For example, take your Goodyear's...

280 A B

280 represents the treadwear rating

A represents the traction rating

B represents the temperature rating

I have a feeling you and everyone else probably knew that much...now for the mind-numbing details!! I'll provide you with a reader's digest version before I launch into the full-blown engineer's version of the story...

http://www.tiretesting.com/1g-utqg.htm

Every tire is tested against a "reference tire". For whatever reason, the gov't decided that a 195/75R14 Uniroyal Tiger Paw would be the reference tire for every size and type of tire made for passenger vehicles. This tire is called the "standard reference testing tire or SRTT. So the UTQG ratings for your tires are in relation to this Uniroyal Tiger Paw...keep that in mind.

Treadwear Testing :: Using a government specified test procedure, tires are tested on a gov't specified test course, side-by-side with SRTT tires. Based on wear projections, the tires are given a treadwear number relative to the SRTT. SRTT = 100. So your Falkens are projected to last TWICE AS LONG as the SRTT. Keep in mind that the SRTT is an all season Uniroyal Tiger Paw. That makes this number pretty useless, don't you think?? Can you say a tire rated "200" is stickier than one rated "260"?? Not really...but people like to do that. Tire wear is also a factor of the footprint shape, tread depth, load, inflation, etc. So this number isn't really a "fair" indicator of tread compound "stickiness".

Traction :: This is a wet braking test typically performed @ 20mph, 40mph, and 60mph on gov't specified surfaces. Based on the amount of stopping force the tire provides, a correct value for the COEFFICIENT OF FRICTION (CoF) developed between the tire and road can be extrapolated from test results. The SRTT results are corrected to values of 0.35 & 0.50 for the CoF on concrete and asphalt, respectively. The other ratings are all determined relative to the SRTT...

SRTT = 0.35 for concrete & 0.50 for asphalt

AA > 0.38 for concrete & > 0.54 for asphalt

A > 0.25 for concrete & > 0.47 for asphalt

B > 0.26 for concrete & > 0.38 for asphalt

C -->> corrected values didn't meet any other criteria (aka - crappy tire!)

So...you buy a tire with an "AA" traction rating. All that means is that it can develop 7.5% more stopping force on wet asphalt than an outdated, all-season, Uniroyal Tiger Paw. You can imagine that "AA" is pretty easy to attain when you have a directional tread pattern. So again, this number is somewhat meaningless!!

Temperature :: Tires are tested on an indoor flywheel under controlled conditions for load and inflation...again, tested against the SRTT Uniroyal. Based on the condition of the tire when it is removed from the durability test, it is given a rating of A, B, or C compared to the SRTT. Because of the robust construction of just about any "speed-rated" tire, you'll have a hard time finding a performance tire that is not rated "A".

So...big picture, the UTQG ratings don't really tell you much. Well, I suppose they tell you how a tire stacked up against an all season tire with outdated technology, but not much else. It gives you a feel for what kind of tire you're buying, but I don't think we should split hairs over "AA vs. A" or "280 vs. 180"...there really isn't much you can conclude from that.

Thanks for reading...if you have more questions keep them coming!

Matt

 

awesome reply! thanks!