CST Tire Treadwear Rules Change

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Bob Endicott
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CST Tire Treadwear Rules Change

Postby Bob Endicott » Wed Aug 22, 2018 8:03 am

The current CST rules say that tires must have a treadwear rating of 140 or higher. I don't think that any of the tire manufactures even make a 140 tire anymore. In the spirt of CST, which is to allow any car that can be truly driven on the street to and from an event, I would like to see the treadwear rating changed to 100. This would allow people that are doing track days with the Toyo R888 and R888R to run in CST instead of CSM. These tires have a real tread pattern, unlike the Hoosier and BFG DOT race tires which are basically slicks. They are inexpensive and wear well and don't seem to heat cycle out. The R888R is available in sizes from 13" all the way up to 20". A set of 255/40X17's would cost $205 at The Tire Rack. I'm going to ask that at the next Committee meeting that this be brought before the Voting Committee for a vote. Anybody have any thoughts, positive or negative?

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Anthony Porta
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Re: CST Tire Treadwear Rules Change

Postby Anthony Porta » Wed Aug 22, 2018 8:37 am

CALIFORNIA STREET TOURING (CST):
Vehicles eligible for CST must comply with the rules of CSM, with the exception that all of the
tires mounted on the car must have a TREADWEAR number of 140 or higher molded by the
manufacturer on the sidewall.

In the title it mentions Street Touring, I believe we should have a 200 treadware limit to match what is currently in the rules for street touring as well as a minimum molded depth of 7/32" as specified by the manufacturer.

If it were 100, there is only 1 tire that would fit my car, the Maxxis RC1 which is 100 treadwear and looks like this.

RC1-2.png
RC1-2.png (272.29 KiB) Viewed 1027 times


There are a very limited set of 100 treadwear tires for 15" wheels, in addition to everyone wanting to compete in that class having to go down to 100 treadwear tires to be competitive. When looking at the different tire brands and products there are far less choices and options in the 100 treadwear styles.
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Re: CST Tire Treadwear Rules Change

Postby Jonathan Lugod » Wed Aug 22, 2018 9:55 am

The Maxxis RC1 is hardly a threat IMO. I have driven fresh ones and they aren't anywhere close to sticky at 120º compared to when they are 180º on track. A BFG or RE71R will be grippier even when comparing 245 vs 205.

I agree with Bob that CST should be more open as those type of participants do gravitate towards CST. Most of the people I know in CST have a lax'd attitude towards autocross (terms of prep) and often do track as well.
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Sean Fenstermacher
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Re: CST Tire Treadwear Rules Change

Postby Sean Fenstermacher » Wed Aug 22, 2018 10:09 am

I don't really see a reason to really limit CST to 200tw, as the class is supposed to be a "Run What You Brung" class.

I can agree that the 140tw is a bit outdated nowadays.

Honestly, I am not sure if there is any downside to NOT lowering the treadwear restrictions to 100tw.
At this point in time, none of the semi-slick tires have proven to be faster at autocross than the BFG Rival S 1.5 nor the Bridgestone RE-71R.
So it would be likely to think that the more serious CST competitors would still compete on the top level 200tw tires to get the best overall raw time.

Lowering the treadwear restrictions may invite more "track" oriented drivers to come play, as they would now have a place to compete in a class with their car "as-is",
as well as possibly accommodate better for for vehicles at that use 19" and 20" tires. Selection for BFG and Bridgestone is very limited for those larger sizes.

Here is a recent test done with the R888R vs some of the 200tw tires:

http://www.tracktuned.com/feed/2017/3/1 ... ankook-rs4

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Reed Gibson
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Re: CST Tire Treadwear Rules Change

Postby Reed Gibson » Wed Aug 22, 2018 1:24 pm

I see no reason to not allow this, it's a run what you brung class. If they can drive the car "legally" on the streets then why restrict them to a specific treadware. Like Jon mentioned, the current crop of "street legal slicks" don't work nearly as well at autox temperatures as the current crop of 200 tw tires do. This should be an easy update to the rulebook for next year and I'm sure we can let people run in class for the remainder of the current season (maybe we just ask the CST field if they are ok with the updated rule change).

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Marshall Grice
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Re: CST Tire Treadwear Rules Change

Postby Marshall Grice » Wed Aug 22, 2018 2:00 pm

Why wouldn’t we just kill csm while we are at it? And why limit the treadwear to 100, why not cut straight to the chase and make the treadwear limit something like 41 (hoosiers are treadwear 40)?

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Sean Fenstermacher
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Re: CST Tire Treadwear Rules Change

Postby Sean Fenstermacher » Wed Aug 22, 2018 2:33 pm

Marshall Grice wrote:Why wouldn’t we just kill csm while we are at it? And why limit the treadwear to 100, why not cut straight to the chase and make the treadwear limit something like 41 (hoosiers are treadwear 40)?


Is there a faster autocross tire you know of from 41tw to 200tw than the RE-71R/Rival S?
If not, then why not?

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Re: CST Tire Treadwear Rules Change

Postby David Barrish » Thu Aug 23, 2018 6:38 am

I would second Bob's request to update the tire rating to 100. In my case Toyo RA1's.

Being able to run the tires that I will be using on my refreshed NASA spec BMW lets me have seat time at an autocross on the combination that I will be driving on the track. This combination will not be as fast as the car on RE71's, but the RA's last longer on the track.

Making the change is removing the need for yet again another set of tires and rims to entice a potential group of drivers. Again, Track time is not like our events. But seat time is what some of us really need before we go all out on a track, doing "track days".

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Reed Gibson
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Re: CST Tire Treadwear Rules Change

Postby Reed Gibson » Thu Aug 23, 2018 7:05 am

David Barrish wrote:I would second Bob's request to update the tire rating to 100. In my case Toyo RA1's.

Being able to run the tires that I will be using on my refreshed NASA spec BMW lets me have seat time at an autocross on the combination that I will be driving on the track. This combination will not be as fast as the car on RE71's, but the RA's last longer on the track.

Making the change is removing the need for yet again another set of tires and rims to entice a potential group of drivers. Again, Track time is not like our events. But seat time is what some of us really need before we go all out on a track, doing "track days".


Yeah I like this sentiment. It allows people to bring out their more track oriented cars without having to feel alienated by the Solo rulebook. CST is just for local fun; having big tire style discrepancies shouldn't ruffle too many feathers when you have all manners/levels of prepped cars competing against each other already (RX-7 vs Mini vs S2000 vs etc.).

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Michael Bradley
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Re: CST Tire Treadwear Rules Change

Postby Michael Bradley » Thu Aug 23, 2018 10:20 am

So I figured I'd chime in here as I'm the only one in the comments that actually competes (regularly) in CST. I was always under the impression that CST followed the treadwear rules of street tire classes and when street tire classes changed from 140tw to 200tw CST followed suite. Of course tire manufacturers also paid attention to this rule change and now all the fast tires are magically 200tw as well. I and my fellow competitors changed with the rules with little to no drama. So here's my only concern, are we modifying the tire rules to accommodate the occasional track day person who tries autocross for the first time never to see them again because they found it to difficult and decided to stick to track days? I'm all for change for good reasons, I'm just not convinced (yet) that this is one. My 2 cents

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Marshall Grice
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Re: CST Tire Treadwear Rules Change

Postby Marshall Grice » Thu Aug 23, 2018 1:43 pm

It should be obvious (my snarky comment clearly didn’t come across well) but we have an entire class (csm) dedicated to lower treadwear tires that people can run right now. Why can’t the track day crowds run in that class? What problem are we solving?

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Sean Fenstermacher
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Re: CST Tire Treadwear Rules Change

Postby Sean Fenstermacher » Thu Aug 23, 2018 2:19 pm

How about we just vote on an upcoming meeting and ask club reps to poll their members in the meantime?

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Jonathan Hartendorp
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Re: CST Tire Treadwear Rules Change

Postby Jonathan Hartendorp » Thu Aug 23, 2018 2:41 pm

I agree with Porta: The "ST" in "CST" stands for "Street Tire" and we should stick to it (literally) being a "run what you brung" class ON street tires.

BUT if we do change the rules to a 100 treadwear minimum for CST, we keep it at that and go no lower...keep the R-comps and slicks in SM/CSM class where they belong thank ya.

As for the occasional track day guy who tries autocross for the first time: Why not stick them in CSM class like Marshall said?
OR stick them in "NOV SM" class or "TO" if they feel intimidated OR just don't wanna run with the big dogs yet. If they really get hooked on AutoX and want to stay, they then could decide what class they want to compete in be it CST or CSM and with the appropriate treadwear tire that fits the rules.

I think more competitors have gravitated towards CST than CSM because of the open, less-restraining rules for car prep and the friendly-fun competitive atmosphere of the class along with the camaraderie amongst the drivers....plus we don't got enough monies for any R-compound purple crack :lol: :P ;)

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Sean Fenstermacher
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Re: CST Tire Treadwear Rules Change

Postby Sean Fenstermacher » Fri Aug 24, 2018 9:34 am

Looking 2018/2017 years of overall results say that no one has raced in CSM since 2016.

With CST already having very strong large turnout year after year, perhaps we can compromise by tweaking the rules for CSM to restrict tire wear ratings to DOT tires of 41tw and above?

That way, if it turns out that there is a decent population of drivers with only access to these DOT "track tires" that want to come and play, they might regularly return to future events with friends without fear that someone with a set of Hoosiers will show up and ruin their day.

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Re: CST Tire Treadwear Rules Change

Postby Eddie Atherton » Tue Aug 28, 2018 11:38 pm

Why not just simplify it: If the tyre is DOT street legal it's CST. If it's not DOT then it's CSM.

Cheers.

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Anthony Porta
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Re: CST Tire Treadwear Rules Change

Postby Anthony Porta » Wed Aug 29, 2018 7:28 am

Eddie Atherton wrote:Why not just simplify it: If the tyre is DOT street legal it's CST. If it's not DOT then it's CSM.

Cheers.


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Jason Swindle
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Re: CST Tire Treadwear Rules Change

Postby Jason Swindle » Wed Aug 29, 2018 3:28 pm

This is the inevitable slippery slope that the whole moving "stock" back to "street tires".... The number the manufacturer molds on the side of the tire has very little to do with the durability or grip....


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