Automotive Thinker

The SCCA and other sanctioning bodies typically have a rule that separates race tires from street tires for classing purposes. Currently, a treadwear rating of 200 is what this rule is based on. Any tire that is equal to or greater than 200 is considered a street tire, while everything below is a race tire. But there is a problem with this; the treadwear rating number, also known as UTQG (Uniform Tire Quality Grading) is arbitrary and means absolutely nothing.

Before we can really look into the problems associated with the 200tw tire rule, we first need to understand why there is a rule for this in the first place, and honestly, I don’t know the exact reason but I strongly suspect that the goal of it was to keep costs down. These ruling bodies are trying to make the sport more attractive to less serious racers or to those who don’t have a way to get their car to the track with a second set of track-only tires. I can see that the idea is to have a “run what you brung” classification so daily drivers and street cars can participate in an event.

To show how meaningless the treadwear number is, before the SCCA had the number set to 200, it was 140. All of the tire manufactures responded to the rule change in 2014 by relabeling their tires to 200. This has been proven by empirical evidence that the 200tw versions of these tires performed and wore the same as their older 140tw counterparts. So this raises the question: what the heck was the point to raise the treadwear number to 200?

Regardless of the reasons for the rule change, the fact of the matter is that 200tw tires are actually full blown race tires in a thin disguise; and everyone seems to know it judging by how they treat them exactly like race tires. It also seems like the SCCA knows that the rule is BS as well, since they have made a list of special exceptions. I tend to run in this CAM class for autocross, and right out of the SCCA rule book you can see they have made exceptions to some 200tw tires:

So what effect is the 200tw rule actually having? There seems to be a lot of cheap, no-name, or foreign tires out there that might have been usable but are simply not allowed due to the rule. For example, these tires include the Nankang NS-2R, Achillies ART-K, Accelera 651 Sport (100tw), and a host of other unheard of companies and tires made around the world. I’m not sure why these no-name manufacturers don’t simply relabel the tires as 200tw, but after looking into some of companies, it looks like they don’t even speak enough English to get their twitter ad’s right. So who can blame them for not knowing the the SCCA rule book. Maybe selling the tires here is is an afterthought.

There is also some things I don’t know. The National Highway Traffic Safety Administration, according to wikipedia on the topic of UTQG, ‘has the right to inspect the tire manufacturer’s data and can fine them if inconsistencies are found’. Maybe there is some under-the-table dealing going on here with companies like Bridgestone and their RE-71R which is considered the most suspicious tire around. Smaller companies like Nankang simply don’t have the clout to pull off the same back-room deal. I have my suspicions that something like this might be the case since there is quite a bit of money at stake.

In researching this topic, I have found that other people are also suspecting less than honorable dealings and agreements concerning 200tw tires. Other than the RE-71R, the other fast (and very expensive) tire on the market right now is the BFG Rival S. I found some comments on the Corvette Forum and there is theories out there stating tires like the Yokohama A052 and the Kumho v720 ACR were specifically banned by the SCCA from 200tw classes (even though labeled as 200tw) because they were subtracting from Rival S sales. Allegedly, a special relationship exists between the SCCA, TireRack, and BFG…

Conspiracy theories aside, the bottom line is that the treadwear rule is doing the opposite of what it was most likely intended to do; that is, its actually increasing the cost of tires and being competitive. I’m trying to think of ways to replace the rule and I have thought of two, but both are problematic. My first idea is that the SCCA or whatever sanctioning body can perform their own tests to get a real objective number. My other idea is to set a price limit based off of the average market price of the tire.

The problem with my first idea of having the sanctioning body do their own testing is that I highly doubt that these organizations have the ability to perform the tests competently, and like any other governing body, they are also susceptible to backroom dealings. Its also not possible to independently test every tire on the market and make a book of approved tires since there is just too many out there. Maybe instead of treadwear, durometer could be used and could be tested at tech inspection for an event. Though, durometer is temperature dependent which could pose a problem. The entire purpose of doing this would be to prevent manufacturers from making real race tires and labeling them as 200tw tires for the street tire class. This would then hopefully allow real street tires, which tend to more affordable with lots of choices, be competitive… I think this system would be difficult to pull off.

My second idea has problems of its own, but might be better. Initially, I found a problem with the tire price changing drastically by the size. For example, a 205 wide tire for a 15″ wheel is typically way cheaper than a wider size for a larger wheel. Maybe an average of the prices for all of the sizes the tire comes in could be used? I was interested to see how this would work so I went to TireRacks site and did this for the BFG Rival S 1.5 tire. The average price I got was $240.66 per tire. So, if the sanctioning body were to set a price limit of, say, $200, then this tire would not be able to be used using this ruling format.

But of course, the market is what sets the tire price in the first place. Setting a price limit is playing with the market and is most likely going to lead to unintended consequences. But really, setting a treadwear limit is also playing with the market and we are currently dealing with the outcomes of that. I’m thinking that maybe there will be shortages and I expect the manufacturers to figure out ways to throw off the average, like make a fake odd size like a 106/63r12.6 for a dollar. Of course the rule would have to be tweaked to prevent something like this.

I’m not sure if these ideas are any good, but I think something needs to be done. Otherwise, to be competitive in a street tire class, you will have very few but very expensive options that are in stark contrast to the spirit of the rule.

Notes:

Recently I found an article on TireRacks website from 2015 talking about the then new RE-71R which can be viewed HERE. This article strikes me as odd because it had this to say about the RE-71R “The new Bridgestone Potenza RE-71R carries the same 200 UTQG wear rating, but is expected to have a bit shorter treadwear than the older Potenza RE-11A.”

Does the RE-71R wearing shorter but still being labled a 200tw tire not sound suspicious?