For the new autocross classes like STR, etc., you need to have tires with a UTQG rating of 140, but the rating isn't literally seen on the tire's sidewall. Instead, you get a bunch of other stuff like tread wear, traction, and temperature. So how do you go from there to the UTQG value?

thxZ

Whenever i buy tires the UTQG rating is listed, but you are correct thats its not on the sidewall. I would just see if you can lookup your tires at tirerack.com and see if they list the rating. Its important to note though that not all tires need to have that rating, i know mud and snow tires are exempt so its possible certain race tires have the same rules.

I thought that the place where you buy the tires should have the UTQG values. I haven't talked to them since it's a new thing for me, and my tires are fine for everything else.

It's just that the new ST classes for SCCA autocross require tires with a UTQG rating for 140 or more. How would you, or the autocross tech guy, know if your tires are compliant?

Of course mud and snow tires are exempt- I doubt they would ever get anywhere close to the limit of temperature, or wear.

Edited October 23, 201212 yr by TomoHawk

The UTQC is the whole suite of ratings. I believe the one the new rules are referring to is the Tread wear rating. The idea is to not allow the use of DOT-R tires (which frequently have ratings of 50 or so).

Normal people would use the UTQC when shopping for tires to compare tread life, its almost like a benchmark. I think the idea like Arne says is to just make sure you have "street" tires on your ride and rather than a complex set of rules they just adopted a minimum level of an existing standard. Tire rack has a good article explaining the whole topic:

http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=48

Ok, so I looked up some tires on TireRack.com, and found some BFG Radial T/A tires, size: 215/60R14 and it has a UTQG rating of 400AB (it says this in the description box for the tire.) The a service description was 91S.

Treadwear: 400

Traction: A

temperature: B

Load Index 91: 1356 LB per tire

Speed rating S: 112 MPH this on the

So it looks like that tire should be adequate for some autocross in the stock or STU classes.

Arne is correct that the rules require a "minimum UTQG treadwear rating of 140" so thanks for clarifying that. The temperature rating is unfamiliar to me, but that should be easy to look into. I suppose it only matters if you're doing something like driving long-distance at 100 MPH through phoenix, AZ in August?

Edited October 23, 201212 yr by TomoHawk

It's on the sidewall, they are talking about 140 treadwear tires. This is not complicated. The Tirerack article does a pretty good job of explaining things.

EDIT: We posted at the same time, looks like you figured it out. The TR article describes what the temp and traction ratings signify.

It would be nice to know where to look on the sidewall, like near the outer tread, on the (main ring) or by the wheel rim.What does it look like: "UTQG: 400AB" or something else (400AB)? It's not as prominent as the tire size numbers.

I looked at the tires on my DD, and they have "treadwear 540"? (CooperTires 185/65/R14) I suppose passenger tires can wear less (over 50,000 miles) and still be safe to drive, compared to a higher-performance tire.

Edited October 23, 201212 yr by TomoHawk

It would be nice to know where to look on the sidewall, like on the (main ring) or by the wheel rim. It's not as prominent as the tire size numbers.

The best advice I can give is it's somewhere on the sidewall. Usually doesn't take long to find it unless the tire is caked in dirt.

If you're buying new tires, that information is available to you without having to look at the sidewall.

It doesn't actually say "UTQG" on there anywhere. You just look for where it says "treadwear" or "load" or "temperature" or whatever rating value you are interested in.

I suppose there's a reason for having a "minimum UTQG treadwear rating of 140" for the autocross ST classes as it equalizes things between cars, at least in that respect.

Edited October 23, 201212 yr by TomoHawk

It doesn't actually say "UTQG" on there anywhere. You just look for where it says "treadwear" or "load" or "temperature" or whatever rating value you are interested in.

Correct.

I suppose there's a reason for having a "minimum UTQG treadwear rating of 140" for the autocross ST classes equalizes things between cars.

Or rather, they attempt to equalize. One 140 treadwear tire will differ from the next, depending on manufacturer. This is due to the way that the treadwear rating is determined. Treadwear ratings are something that can be played with and this is actually somewhat described in the TR article.

To truly equalize tires, everyone would have to run the same tire. With that said, none of this matters much if you're not trying to win National Championships.