What if we told you that a tiremaker could put whatever treadwear rating it wanted on the sidewall of a tire? And that the National Highway Transportation Safety Administration does no compliance checking on that rating?
How would you then feel about motorsports rule sets that require tires rated at 200tw or higher? It’s the dirty little secret of the …
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Reading this made me reach out my first Solo rule book. Some cool tire ads in there.
SCCA's first National Solo rule book...
I dig the small-format SCCA rule books.
Honestly reminds me a LOT of the early "fastest street car" days with McCreary clay track tires, retreads, and then the emergence of the Mickey Thompson ET Street, then the discovery of 12" wide "10.5" tires leading to the "10.5W" classes and "true 10.5" classes.
In reply to David S. Wallens :
The artwork on that 1972 is great. MGs and a Manx, along with an intrigued lady.
Keith Tanner said:In reply to David S. Wallens :
The artwork on that 1972 is great. MGs and a Manx, along with an intrigued lady.
I can't speak to the lady, but MG TD was a real fixture in early SCCA Solo. And the Manx was popular in A-Modified, believe it or not. Who'd a thought that was "unlimited".
In reply to Andy Hollis :
This is why I built my MGA to run autocross, and why I'm helping my dad to upgrade his MGTD to bring it out too.
My dad managed automotive testing centers for about 25 years and most of the testing is tire or durability testing. Not all of the testing is out of San Angelo. I lived there 4 years while dad was in this business. This article is good but not quite there. The standard tire was a bias ply design that dates back to the DOT reg. The standard tire had a tread wear rating of 100. New tires last a lot longer have better traction and use way better tech.
No one puts a standard tire on a car today. I sure wouldn't drive a bias ply tire with 3 modern tires. The mileage life of the standard tire is well documented. The tire testers take temperature measurements, inflations, treadwear measurements and even use laser holography if the contract specifies it. They generally run fleets of four cars for each test in case of a failure. The contracts usually go to a set mileage. The cars typically see 500 miles a shift, two shifts a day 5-6 days a week. Off-road tires get totally different tests but have highway tests too.
I've known of test fleets based out of San Angelo, Ft Stockton and the San Antonio area (Devine). I don't know who is still in business or not. My dad hasn't been in that business since 2006 or so.
Dad was also a regional SCCA guy in TX back when those rules were written.
In reply to David S. Wallens :
I dig the small depth.
Great article guys. We are living in a golden age of amazing rubber. Just take a looksie at the typical autox delta between the old standard Hoosiers and the new crop of super 200's.
Planning to do a head to head on my FSP Rabbit this summer between the 255/40/13 A7's and the new Kumho V730 205/50/15. Not exactly a fair fight but will be surprised if they aren't pretty close.
In reply to AnthonyGS (Forum Supporter) :
Your info is a little out of date. The reference tire is now a more modern one...16" radial versus the old 14" bias-ply. And made by Michelin (branded Uniroyal). There are now only two official routes used for UTQG treadwear testing...both in San Angelo. But, many third parties offer routes elsewhere that can be used "for development purposes". And since NHTSA does no compliance checking, that's close enough for many situations. In fact, the information I was given was that way more tire treadwear ratings are "engineered" these days rather than empirically tested.
I was about to ask "where do you get a bias-ply 100TW tire that's not a slick?" And I figured 100TW equals out to 5000 miles. People forget how short tire life was back in the old days especially when you figured in all the punctures and blowouts they suffered back then. About 20 years ago I was on probably 10-year-old old P6s and hit a bag of trash blown in front of me during a violent windstorm. It was literally a beer bottle that took it out. I was like "a beer bottle, really?"
GCrites said:I was about to ask "where do you get a bias-ply 100TW tire that's not a slick?" And I figured 100TW equals out to 5000 miles. People forget how short tire life was back in the old days especially when you figured in all the punctures and blowouts they suffered back then. About 20 years ago I was on probably 10-year-old old P6s and hit a bag of trash blown in front of me during a violent windstorm. It was literally a beer bottle that took it out. I was like "a beer bottle, really?"
As mentioned in the story, 2003 was a turning point in the US tire industry, as a result of the Ford Exploder/Firestone rollover debacle. NHTSA and the industry worked together to tighten the standards resulting in FMVSS 139 (previous was FMVSS 109).
Steel-belted radials became the new norm. Many of the early examples were indeed rugged but handled like crap. It was a huge reset for the performance tire biz, as some figured it all out a lot quicker than others.
Thanks for diving into this Andy. Great presentation. I was the guy at Yokohama in the late 80s and early to mid-90's who led the autocross tire development program, including the evolution from A008R to the 8RS (first as a dual use track/autocross and later solely track/time trial), and then 8RS2 (autocross). We did have each new generation of tires tested in San Angelo to validate against our internal testing & engineering data, but obviously didn't re-test when we would change construction and compound. We did create an optimized tire each year for Nationals (as did BFG), but the number of times that there were "special tires for special drivers" was very, very minimal. We didn't engineer them that way; but in testing, some drivers would prefer a different test tire than what we felt struck the best balance between performance and drivability for Nationals. So a few sponsored drivers were allowed to run on a test tire that they preferred over the official Nationals tires that we would produce. They weren't necessarily faster tires, they just were slightly different in characteristics. The official tires for Nationals did need to strike a balance between performance and drivability -- not all customers could really drive a tire at 9.5/10ths all of the time! Most years, we would have one Nationals construction + compound for smaller/lighter cars and one for larger/heavier cars. They weren't the same. In those days, we mostly used a tw rating of 80 for the autocross versions, but we could have supported a 200tw rating easily. Anyway, hope that additional context is helpful. Great article!
bslarsen728 said:Thanks for diving into this Andy. Great presentation. I was the guy at Yokohama in the late 80s and early to mid-90's who led the autocross tire development program,
....
but the number of times that there were "special tires for special drivers" was very, very minimal.
Welcome back to the madness!
One of my favorite stories from that era was the Reitmeir/Tunnell BMW tire swapping in grid at Solo Nats. A008RTU, I believe. Only two special sets available and flown in, but had to last for four drivers for both the Pro Finale and Nats. Their BMW 318's, ran in different classes (4door vs 2door)...so H Stock and E Stock. Plus the L classes for each. Which put them in grid constantly through most of the day. One set of tires was being hot swapped between the two cars, the other car being left up on stands...in grid.
The details are a bit fuzzy, but the Tunnells are still good friends. I checked with Bob the other day to proof the story and he said "I can neither confirm nor deny that ever happened". :)
Fun times.
As for running changes during the year (again, none of this was against the rules)...here's me doing a blind taste test of three variants of the latest BFG Comp T/A R1. This was a go-kart track in upstate NY which could facilitate cars at autocross speeds. The Monday after a Pro Solo weekend in NJ, we met the BFG support semi there. The resulting tire was in production within a month. Being based in Akron has its advantages for logistics.
Y'all really need to scold the ex-Buzzfeed staffer writing your titles lately. That article is EXACTLY how we all thought the process worked...
In reply to cyow5 :
Except the part about driving around on 3 tires one type and one tire that isn't like the other 3. That only happens when your local genius goes to the used tire place.
In reply to Andy Hollis :
Yeah - that happened. Stacy, Jeff, Bob and Patty were (and are) great folks. Things settled down a lot after the 008RS and RS2 came along ...
In reply to Andy Hollis :
And lots (and lots) of Nationals testing in Ardmore ... Heard recently that Michelin is closing that plant. Sad.
I had a set of the Kuhmo V710s. I ran them on a y2k Camaro Z28 and then on a y2k Corvette FRC. I loved them. Fast and relatively easy to find the limit for a race tire.
Really great article. Fun read. I would love to read more about those tires used throughout the eras.
In reply to Andy Hollis :
I think that intrigued lady might be my ex-wife and multi-time Solo National champ Linda Pobst. 
Although '72 may be a couple years too early.
Andy, congrats and thanks on another fantastic and thorough article. So much good info! I read somewhere when TDW 200 was introduced that there was no enforcement. Uh, oh, I thought. Your test articles here in GRM do a fantastic job of defining performance, and in fact, SCCA could use them as a guideline that is far more accurate than allowing manufacturers to put whatever numbers they want on tires. As long as they don't buy YOU. 
(That McLaren must be expensive to fix all the time)
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