Cal Club Autocross Forums

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The SEB is seeking member input on the possibility of changing the minimum treadwear rating for the Road Tire (RT)
Supplemental classes to 200.

If this goes through, it'll be interesting to see if any of the tire manufacturers currently supplying 140+ tires change their treadwear rating.

I don't really see the logic behind changing the minimum treadwear rating for "Street" tires. Sounds like a thinly veiled attempt to ban the Toyo R1R without actually using the exclusion list.

The hardcores will test a bunch of 200tw tires and find the fastest, the lemmings (myself included) will follow suit. No net gain that I see.

Edit: Sorry to burst your bubble Kurt, but we are not so significant that manufacturers will change processes to suit our needs. Believe it or not there is a method to deriving the treadwear rating of a tire. The manufacturers would not be able to just slap 200 on a tire that was previously made as a 140 without either changing the rubber compound, or molding it to a deeper tread-depth.

Sebastian Rios wrote: Believe it or not there is a method to deriving the treadwear rating of a tire. The manufacturers would not be able to just slap 200 on a tire

No, they can't slap a higher number on than it earns during the tests, but there's nothing stopping them from putting a lower treadwear number on it than resulted from the tests.

The tire manufacturers we heard from on the SEB wouldn't reveal whether or not they've done that.

Dunlops are 200 ;). LeMons has a 200 Treadwear limit and everyone runs either Dunlops or Falkens.

Completely unrelated to the content of FasTrack:
Does anyone else use Chrome as their browser that can't ever get these pdfs to download? If I click the link in Safari (on Mac) or on Firefox (on Linux) they download fine, but in Chrome on both OSs the PDF doesn't download. I have this problem with all the other PDFs on the SCCA's website as well, like the solo rule book. If it's not just me then I'll try and get in touch with their web people...

A number of years ago Toyo changed RA1's from 60 wear to 100, with no change in anything. They simply said that after years of use and seeing how well they wore, 100 was a more realistic number. They actually said yes, you can run 60's with 100's ... there is NO difference.

Mike Simanyi wrote:

Sebastian Rios wrote: Believe it or not there is a method to deriving the treadwear rating of a tire. The manufacturers would not be able to just slap 200 on a tire

No, they can't slap a higher number on than it earns during the tests, but there's nothing stopping them from putting a lower treadwear number on it than resulted from the tests.

The tire manufacturers we heard from on the SEB wouldn't reveal whether or not they've done that.

Why would a manufacturer want to do that, and if they did, why would I care?

Jeff Stuart wrote:Dunlops are 200 ;). LeMons has a 200 Treadwear limit and everyone runs either Dunlops or Falkens.

Completely unrelated to the content of FasTrack:
Does anyone else use Chrome as their browser that can't ever get these pdfs to download? If I click the link in Safari (on Mac) or on Firefox (on Linux) they download fine, but in Chrome on both OSs the PDF doesn't download. I have this problem with all the other PDFs on the SCCA's website as well, like the solo rule book. If it's not just me then I'll try and get in touch with their web people...

I got it to work on mine, but the same settings didn't work on a different computer..

go to > chrome://plugins/
then disable the chrome PDF viewer
and make sure the adobe viewer is enabled

Sebastian Rios wrote: Why would a manufacturer want to do that, and if they did, why would I care?

I know when I was first getting into the sport, I shopped tires based heavily on tread-wear. Autocross rules (as well as many other forms of racing) basically teach people that lower tread-wear == faster, even though it's not necessarily true, so it's not surprising (to me anyways...) that tire manufacturers would want to put a lower number on the tire to make people think it was faster.

Nicole Nagler wrote: I got it to work on mine, but the same settings didn't work on a different computer..

go to > chrome://plugins/
then disable the chrome PDF viewer
and make sure the adobe viewer is enabled

That worked for me in Linux, thanks!

Jeff Stuart wrote:I know when I was first getting into the sport, I shopped tires based heavily on tread-wear. Autocross rules (as well as many other forms of racing) basically teach people that lower tread-wear == faster, even though it's not necessarily true, so it's not surprising (to me anyways...) that tire manufacturers would want to put a lower number on the tire to make people think it was faster.

Sure that works for one set of tires, but the observant new folks will see what tire the fast guys are using and follow suit. I too had what I thought were fast tires when I started...they were Z-rated! I quickly bought some Falken Azenis RT-215 after my first couple of events.

Kurt Rahn wrote:

The SEB is seeking member input on the possibility of changing the minimum treadwear rating for the Road Tire (RT)
Supplemental classes to 200.

If this goes through, it'll be interesting to see if any of the tire manufacturers currently supplying 140+ tires change their treadwear rating.

As Mike mentioned, they can only move it to a lower number. Keep in mind, and I think this is lost on most consumers, that it is a treadwear rating, not a treadsoftness rating.

Tread depth, softness, differing compounds all factor into how long a tire will last on the test circuit.

Sebastian Rios wrote:

Mike Simanyi wrote:

Sebastian Rios wrote: Believe it or not there is a method to deriving the treadwear rating of a tire. The manufacturers would not be able to just slap 200 on a tire

No, they can't slap a higher number on than it earns during the tests, but there's nothing stopping them from putting a lower treadwear number on it than resulted from the tests.

The tire manufacturers we heard from on the SEB wouldn't reveal whether or not they've done that.

Why would a manufacturer want to do that, and if they did, why would I care?

A. Marketing.
B. Because it explains how a manufacturer could nearly instantly raise their UTQG rating in certain circumstances.

Star Specs: 200
615K: 200
RE-11: 180
Ecsta CS: 180
AD08: 180
RS-3: 140
R1R: 140

As Jeff said, Dunlops and Falkens. It would make RT* close to a spec tire class, at least with the current crop.

Playing off of Mike's comment, is the thought behind this rule proposal to force the tire manufacturers to show their hand or something? I can see Hankook and Toyo "lowballing" down to the ST* minimum of 140, but why would Bridgestone, Kumho and Yoko lowball down to 180? That doesn't make much sense.

Maybe it's a backhanded effort to reduce interest in the RT* classes. Everyone wants street tires, huh? Well, here you go, a street tire class where you can't use two of the most popular autox street tires out there. I wonder if this was proposed by a "must keep racing tires in stock classes" evangelist...

Mike Simanyi wrote:

Sebastian Rios wrote: Why would a manufacturer want to do that, and if they did, why would I care?

A. Marketing.

Anecdote: In grid on Sunday I was talking to someone who was a newb (well, more of a newb than I am). I can't remember who it was, we were parked near each other and chatting between runs. The topic of my new star specs came up and the first question he asked was "what's the treadwear rating?"

Experienced drivers know that UTQG isn't directly correlated with performance, but with experienced drivers marketing doesn't matter. Performance and contigency $$$ does.

Davin Swanson wrote:Playing off of Mike's comment, is the thought behind this rule proposal to force the tire manufacturers to show their hand or something? I can see Hankook and Toyo "lowballing" down to the ST* minimum of 140, but why would Bridgestone, Kumho and Yoko lowball down to 180? That doesn't make much sense.

We aren't the only sanctioning/rule making body to use treadwear ratings as part of the rules. We are one of the few that go as low as 140, however. Lowballing to 180 keeps you in other markets.

Sebastian Rios wrote:Edit: Sorry to burst your bubble Kurt, but we are not so significant that manufacturers will change processes to suit our needs. Believe it or not there is a method to deriving the treadwear rating of a tire. The manufacturers would not be able to just slap 200 on a tire that was previously made as a 140 without either changing the rubber compound, or molding it to a deeper tread-depth.

Bubble not burst...my "question" was a snarky reply to the no-street-tires-in-stock folks who claim that if r-comps were outlawed, Hoosier and Kumho would just slap a higher treadwear on their existing r-comps. It was apparently so subtle that nobody got it.

Davin Swanson wrote:Maybe it's a backhanded effort to reduce interest in the RT* classes. Everyone wants street tires, huh? Well, here you go, a street tire class where you can't use two of the most popular autox street tires out there. I wonder if this was proposed by a "must keep racing tires in stock classes" evangelist...

No conspiracy...they're proposing it for the ST classes as well.

Kurt Rahn wrote:

Davin Swanson wrote:Maybe it's a backhanded effort to reduce interest in the RT* classes. Everyone wants street tires, huh? Well, here you go, a street tire class where you can't use two of the most popular autox street tires out there. I wonder if this was proposed by a "must keep racing tires in stock classes" evangelist...

No conspiracy...they're proposing it for the ST classes as well.

Oh, duh. Would help if I read the whole thing, wouldn't it?

Star Specs: 200
615K: 200
RE-11: 180
Ecsta CS: 180
AD08: 180
RS-3: 140
R1R: 140

From what I recall from the old days, the treadwear rating was a test that the tire manufacturers ran on their own tires. It was not a standardized test and the test varied between manufacturers. So if the Kumho was rated at 180 on their test, if another manufacturer tested the Kumho tire using their test, they might/would probably come up with a different rating. I don't know if that has changed, but in the old days, the treadwear rating was a meaningless number. The manufacturer would like a higher number to market to the general public because the higher numbered tire should last longer. If their primary market is the enthusiast, a lower number would be perferred to indicate it is a "performance" tire.
Unless all tire manufacturers adopt a mandated standardized test, the number is meaningless. The only parameter that counts is how the tire performs on your car.

John Fendel wrote:

Star Specs: 200
615K: 200
RE-11: 180
Ecsta CS: 180
AD08: 180
RS-3: 140
R1R: 140

From what I recall from the old days, the treadwear rating was a test that the tire manufacturers ran on their own tires. It was not a standardized test and the test varied between manufacturers. So if the Kumho was rated at 180 on their test, if another manufacturer tested the Kumho tire using their test, they might/would probably come up with a different rating. I don't know if that has changed, but in the old days, the treadwear rating was a meaningless number. The manufacturer would like a higher number to market to the general public because the higher numbered tire should last longer. If their primary market is the enthusiast, a lower number would be perferred to indicate it is a "performance" tire.
Unless all tire manufacturers adopt a mandated standardized test, the number is meaningless. The only parameter that counts is how the tire performs on your car.

Since the 70s,it has been a standard test, standard course (in Texas), and control tires. Control tires have changed over the decades, so you can't really compare a 80s number to a 90s number.

I thought there WASN'T a standardized industry test, only a test within each company?

Yet the ultimate grip between what's labeled 140 and 200 isn't all that great. Each of those tires has qualities that make it different, for different weight cars and in feel and performance at the limit that makes it apparent why not everyone is running the same 140 tires.

so the main advantage the H and K tires have over real street tires is their "tread" design. All they have to do is change the compound to what ever hardness is required to get the wear rating they need and they will again dominate all other real street tires on the market. So raising the treadwear limit will make the tires last longer but it's likely to increase the price of the tires because the tire companies won't sell as many of them.

I don't believe that the tread design is really the main reason for the performance difference. There have been other tires with very little void area that were not nearly as fast as an A6, V710, or even an R6. Falken RT-215, Yokohama A038/A048.

There is an exclusion list that I expect will be used if a company tries to make a two-groove slick with a high treadwear rating.

I don't see the relevance of that argument to whether the minimum rating for ST should be 140 or 200.

John Stimson wrote:I don't believe that the tread design is really the main reason for the performance difference. There have been other tires with very little void area that were not nearly as fast as an A6, V710, or even an R6. Falken RT-215, Yokohama A038/A048.

There is an exclusion list that I expect will be used if a company tries to make a two-groove slick with a high treadwear rating.

I don't see the relevance of that argument to whether the minimum rating for ST should be 140 or 200.

The tread design alone does not account for the current performance difference. Given similar treadwear the 2 groove tread design will allow a softer compound and thus more performance.

Why the aversion to a 2 groove tread design? It's DOT legal and offers higher autox performance potential. We're not trying to create a level playing field for all tire manufacturers to play in, we're trying to save our SCCA members money by getting more runs out of a set of tires. no?

And my arugment is more based on street tires in stock, i could care less about the treadwear marketing number.