Who Rates Tires -- Gov't or Mfr.?

[pbonsalb]

If Wanli performance tires look like they are a copy of some better known brand performance tires, are they just as good as long as they have the same speed rating? Are the speed ratings the product of official testing or are they assigned by the manufacturer?

Is there good rubber and bad rubber?

Are treadwear numbers the product of official testing or are they assigned by the manufacturer? Is the treadwear rating a reasonable performance indicator -- i.e., the lower the stickier or might some tires with treadwear ratings over, say, 300, be very sticky?

Philip Bradley

 

[tuong]

rate them where, on tire rack. u kinda gotta be more specific on what rating. U mean the Z rating???
but if your thinking of what im thinking about and I would think ur thinking about Tire rack. I dont know, but there rating are pretty accurate MOst of the time

 

[CapriRacer]

UTQG ratings are a US government required rating. There is a standardized test for each of the ratings, but the rating itself is done by the manufacturer and all the manufacturer has to do is be able to justify his ratings. So you have to take the ratings with a degree of skepticism.

Speed ratings are also a standardized test, but not government required, nor regulated. But these are also rated by the tire manufacturer.

Good rubber / bad rubber? I tend to think more in terms of performance parameters that have to be balanced out. A good wearing tread compound usually doesn't have good wet grip. Sidewall compounds that don't crack generally are expensive. Etc.

Hope this helps.

 

[Bamaro]

I think you can sum it up - let the buyer beware. You need to take all the ratings with a grain of salt.

 

[moribundman]

quote:

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If Wanli performance tires look like they are a copy of some better known brand performance tires, are they just as good as long as they have the same speed rating?

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No, they could be better or worse in one or several regards. That said, I've never heard of "Wanli" tires.

quote:

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Is there good rubber and bad rubber?

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Yes.

quote:

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Is the treadwear rating a reasonable performance indicator

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Depends on your definition of "reasonable."

The treadwear number is little more than an indicator of whether a rubber is sticker or better wearing. The higher the number, the longer wearing a tire at cost of stickiness. Around 200 is a good compromise, but the numbers are not really comparable between brands.

There are other factors that determine how "good" a tire is. How many plies does it have? Are there cap plies?

The tirerack does test tires pretty thoroughly, so they are certainly a good source for information.

 

[outrun]

1. US Goverment

2. Department of Transportation Laboratories

No matter what tire you buy make sure it is Traction A, Temperature B at a BARE MINIMUM.

If it is traction B like: Bridgestone Guardsman 3e & Trailhandler. Goodyear SuperSport SSR, certain Toyo lines.....

Run far far away.

The BFG Traction TA and Dunlop Sport SPA2 are DOT Traction AA for thought

 

[Bamaro]

I thought the gov set the standards but the manufacturers supplied the ratings.

 

[CapriRacer]

Not quite.

The UTQG rating - Treadwear, Traction, Temperature ratings - is set by government regulations. The tire manufacturer tests the tires and sets the rating according to the regulations. Be aware that the regulations are worded such that the rating has to be JUSTIFIABLE.

The speed rating is a standard industry test, and the tire manufacturer tests against the standard. In this case, the type of tire is designed to meet a predetermined rating. If it doesn't, the tire is redesigned to meet the rating.

Hope this helps.

 

[XS650]

quote:

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Originally posted by CapriRacer:
Not quite.

The UTQG rating - Treadwear, Traction, Temperature ratings - is set by government regulations.

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I have heard that the wear ratings are a dim indication of what to expect when comparing brands, but are usually fairly good within one brand of tire. Supposidly because the test prcedures are vague enough that the different tire companies test differently.

 

[VaderSS]

On treadwear. It's more marketing than anthing else.

On traction. It's wet sliding (locked up) braking. Has nothing to do with ANYTHING else. Also, a "C" rating has no lower limit... Don't think I've ever seen a "C" rated tire on a car though...

The Heat rating is actually a pretty good indicator of how a tire will handle heat, if it's properly inflated. It is similar to the test used to determine speed ratings.

Speed ratings. The max speed a tire can handle for at least 10 minutes. Again, a pretty good one, as long as the tire is properly inflated, and has not been damaged or improperly repaired.

The best way to pick tires though, is to get reviews from someone who has run the tires you are contemplating, on the same kind of car, with the same kind of driving habits, with the same size tires.

Lacking that, Tirerack survey results are also good, but I've found I disagree with them, to some extent.

[ May 19, 2005, 04:40 PM: Message edited by: VaderSS ]

 

[outrun]

Speed ratings. The max speed a tire can handle for at least 10 minutes. Again, a pretty good one, as long as the tire is properly inflated, and has not been damaged or improperly repaired.

Interesting, I am not a mechanical/automotive engineer to quote definatively, but I thought speed rating is the maximum rated speed for 24hrs under experimental conditions (ie treadmill)

 

[VaderSS]

Nope, they are pressed against a large metal drum and run up to speed in 6.2 MPH steps in 10 minute increments, until the rated speed is met.

 

[CapriRacer]

OK guys. I'm getting a little discouraged by folks who are posting information that is incorrect.

The ECE speed test requires the tire to be tested at the rated speed for 20 minutes. The lead up to the rated speed is in 10 minute increments. (BTW, I just looked this up to be absolutely sure.)

[ May 20, 2005, 07:53 AM: Message edited by: CapriRacer ]