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Greg G.

Rule Change discussion: Non-DOT Approved Tires in ST3/TT3

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Greg G.

Hi Folks,

A bunch of competitors have requested that we look into the possibility of changing the rule regarding the use of non-DOT approved tires in ST3/TT3 (and therefore E0 also).  The request being made is to either disallow their use entirely (probably with the few exceptions we have made in the past for tires that are non-DOT but not actually non-DOT racing slicks), or to increase the Modification Factor from -0.5 to -1.0.   This request would not change anything in any of the other classes, and would only apply to ST3/TT3.  We are soliciting opinions on either of these possible changes here now, and may also do a pole or send out a Survey Monkey to current ST3/TT3 competitors regarding this in the future.  Currently, we have less than 20% of ST3/TT3 competitors using non-DOT slicks.

Here is the current rule:   Tire Type: Non-DOT approved tires (ST1, ST2, ST3 Only) = -0.5
(They are already not permitted in ST4-ST6)

Additionally, keep in mind that we are soon going to release ST rules revisions (in the next few weeks) that will include a rule that will require racers to use the same ST Car Classification form (without changes) for Qualifying and the Race (or forfeit the qualifying position and go to the back of the class/grid for the race).  So, the practice of using different Minimum Comp. Wt, or tires that have different Mod. Factors for qualifying will be going away.  We will give a few months of lead time for this one to take effect so drivers can use up tires they won't need in the future.  And, this rule will only apply to changes to the vehicle that would change the Car Classification Form or require a new Dyno test.  So, for example, in ST1-3, a driver could still run on an "A" tire in qualifying and an "R" tire in the race if desired (assuming no changes to tire size Mod Factors), because there would be no differences on the ST CC Form.  But, an ST4 driver would not be able to, because there is a Mod Factor for "A" tires in ST4. 

The proposed reason that we were given for these requested changes are that the current Modification Factor for non-DOT tires is not enough to cover the performance benefit in ST3/TT3, and that with the large majority of competitors not on these tires, a rule change will prevent the majority from having to switch wheels and tires to non-DOT's to "keep up".  (FYI, none of the above necessarily reflects what my opinion or the opinion of the NASA National is--just describing the request so that a discussion can take place).

Fire away--and please stay objective and civil. 😀

 

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B Esquire

I sent this direct to the rules writers, but here is some really good data to chew on for the masses if you think the current rules for non-DOT slicks are fair and equal :).

1)  My ST1/2 370Z in almost EXACTLY the same configuration, at Buttonwillow in 1CW,  ran a full 4 seconds a lap faster on the Toyo Proxes slick (Flying lizard tire) as compared to the RR. 
 
2)  I ran the numbers on my GT-R, at 3600 lbs and 349 hp, I could bolt on a the biggest non DOT slick I wanted and only loose 16 HP.  Knowing how much difference non-DOT tires make on the GT-R, I would estimate I would still go at least 4 seconds a lap faster.  16 HP is nothing at 3600 lbs, especially if I play with my power curve to minimize it's top end effect.
 
-Brian

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daytonars4
Posted (edited)

Using data from RR’s to argue a 4 second performance gap to slicks makes absolutely no sense. It’s a slow tire compared to a DOT Hoosier. For relevance you would need to compare data from a Hoosier A7 or BFG R1S to a slick. In Midatlantic everyone runs DOT. Our first race of the season was the first time that we had anyone run slicks in ST3 competitively. It happened to be a factory VW TCR. His fastest lap of the weekend was .5 seconds faster on Michelin 265’s than the next racer on 275 DOT BFG’s. Based on that alone I would have to consider the 4 second delta argument as nonsense.  

If the goal is to remove slicks from ST3 then going from .5 to 1 will accomplish that. If your goal is to make the competition level between slicks and DOT then a decent amount of research would need to be put in to determine if for some reason what exists now isn’t already effective. Maybe someone else has relevant data on this? 

Edited by daytonars4

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Clavette

I think the current penalty for slicks seems to be sufficient to dissuade folks from running slicks in the TT3 events that I have driven.  Bumping the penalty up or disallowing it would be fine.  A7's come to temperature so fast, that I still think they are the go to tire for TT3.

That being said, I picked up a set of slicks and will be trying them out for the first time in some DE events.  If I decide to run TT, I'll just jump to TT2 and shoot for maybe a podium finish. I would not plan on trying to run them and adding weight or detuning car to make them work in TT3.  I just can't see them being that much faster than A7's to make it worthwhile even under current mod factors.

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Matt G.

I enjoy my take off slicks in TT3. The slick penalty allows some flexibility in my builds that include lower hp and more reliable cars. Also I can typically find affordable long lasting take off slicks which helps keep my costs of racing low. Am I going to be competitive with the fastest TT3 cars/drivers no probably not. But can I afford above average speed combined with reliability based on my budget slick build? Yes! Aero+Slicks equals a surprisingly affordable package for the mechanically inclined without significant investment in power modification.

I strongly disagree with disallowing slicks. I may argue a stiffer penalty for slicks, but at least it's something I can work with! Personally I would like to see open tire rules employed throughout all of the ST/TT classes with balance penalties adjusted throughout the years as tires evolve and develop. To me "INCLUSIVE" rules allow for greater flexibility and ultimately more participants at the cost of greater attention spent crafting the balance of the rules (sorry Greg)


And I'm not sure I agree with a 4 second delta either, but it is hard to disagree with B.Lock. In my own experience with a handful of competent drivers at my disposal the RR has never been a competitive tire when stacked up against the hoosier. R/A7's are always 2-4 lbs heavier per "size" despite being wider. And in terms of grip they out perform the Toyos even through the current RR carcass. So that 4 second delta may be narrowed using even the R7, and certainly narrowed even further when compared against the A7.

Currently A7's dominate the TT groups, and interesting meta games pop up about which session to deploy the "stickers" in, prompting "Too soon junior" comments across the paddock. This tire needs greater attention more then the non DOT argument I believe, and it's one that I know the admin is closely observing and responding to as well. We haven't seen the qualifying games mentioned in Greg's discussion either so that's interesting but seems like it could be resolved by addressing the Hoosier A7 like the unique tire it is. And that may also help mitigate costs in the TT Hoosier wars as well.

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pbuff

My experience with A7s vs. Slicks (both Yoks and Pirelli)  is both in race group and TT.  The biggest difference I've found is longevity. 

A7s are ready to go at Green flag.....slicks take longer to come in.

The A7s will fall off at the end.....slicks may not

Makes for some real good racing in the last 3-4 laps

I strongly disagree with increasing the penalty or disallowing slicks altogether

The current penalty (.5) is sufficient and significant enough to really make drivers think about the total performance impact of using non-DOTs

 

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daytonars4

If the only data driven concern with slicks is related to their benefit over the longer endurance races, why not just create an addendum specially excluding slicks in endurance racing only? Doesn’t seem necessary to screw up the sprint racing formula for the sake of enduro’s. Or make it 1.0 for only enduro’s instead of the 0.5. I can definitely see how the Hoosier A7 and BFG R1S may not be a viable option for enduro’s. So for them the R7/R1 is a bigger gap in performance to a slick. 

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codename Bil Doe

Minor BoP adjustments are fine to balance tires - A's vs R's, DOT vs non-DOT.

It would be more beneficial to add a rule in which a competitor's set of tires are marked for an event weekend so that each competitor uses only one set if four tires per class per weekend.

This would reduce costs by precluding someone from having multiple sets of new tires for warmup, quali, and race regardless of compound or Saturday vs Sunday.

Rule could also have stipulation for approval of up to one substitute tire in case of a flat.

Very easy to mark tires. It's done in karting events all the time for the same reasons.

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Balroks

I agree with the previous posts.  As it sits currently it's perfectly balanced for the competitor to "choose his/her weapon" for the conditions.  Enduro's should use the current rules as  a "suggestion" at best because those conditions are completely different and it makes the "autocross" tire selection moot at best.  If we're gonna suggest making non-dot's -1.0 may as well make A compounds -0.5 while you're at it lol.  As it sits it's really setup to make us think hard about track, temp, conditions, suspension setup, etc like real teams do.  Anything else you may as well make the RR the "spec" tire for everything.      

Same goes for the .5 for 100 tw DOT's.  If it was really worth the hit we'd all be running it. 

What a lot of guys forget is that lower weight trumps ALL tires regardless of make/model/compound, food for thought.

At the end of the day gents if someone wants to build a killer car he or she is gonna have new shocks, tires, engine, everything at every event so there's no point in chasing him or her with rules but rather push them out with good racing craft. 

Edited by Balroks

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