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daytonars4

Rule Proposal: Tire width and compound mod

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daytonars4

People keep having discussions about width and compounds, mostly privately. So I’ll just toss it out there so it can be formally debated.

 

GTS3 in NE has essentially become 2 classes over the last year. The 3 guys on 315’s at the front with everyone else further behind. Yes, that was the intended goal of the GTS rule set. To build however you want. As builds have progressed people with lesser budgets are being left out. We either address the large discrepancy in pace that has developed or we continue to see racers discouraged and either stop racing or move to ST where they feel they have a chance.

 

The pace of the autocross tires are also known to be far superior to the R compounds but much less durable on number of heat cycles. It’s necessary for GTS to address the performance gap. The fastest guys in class will remain the fastest but these changes at least close the gap to the midfield and make racing more fun and competitive for all.

 

-R1/Hoosier R7/(Maybe BFG R1S) .2 bonus

-Hoosier A7 no bonus

-Slicks -0.5

-275mm and under .3 bonus

-225mm and under .5 bonus

In case you are wondering why I'd skip 245mm. The Hoosier 245 is only 12mm smaller than the 275. Not 30mm as the tire size would suggest.

 

So conceptually a 312whp GTS3 car would be as follows with GTS3 base at 10 to 1

280+mm A7 (10 ratio)       3120lbs

275mm A7 (9.7 ratio)         3026lbs

275mm R7  (9.5 ratio)        2964lbs

225mm A7 (9.5 ratio)         2964lbs

225mm R7 (9.3 ratio)          2902lbs

280+mm slick (10.5 ratio)  3276lbs

275mm slick (10.2 ratio)    3182lbs

225mm slick (10)                3120lbs

 

*A .5 slick ratio for GTS1/2 likely isn't sufficient enough to be a deterrent. With such low power the weight penalty would be minimal and lead larger budget teams to chase optimizing on slicks. So maybe leave it at 1.0 for those classes?

 

Now I have no personal motive on this. Midatlantic didn’t experience the super wide tire craze. But I have seen what it has done in NE causing numerous racers to either leave or consider leaving which has been one of the best GTS region in the country.. The growth of ST during the decline of GTS can’t be ignored if you want the class to succeed.

 

Lawrence Gibson 

Midatlantic GTS2/ST3

 

 

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Emag

I support a tire width rule similar to ST, having a split at 275 as mentioned.  

 

I do not support a compound break as I do not believe that there is sufficient data to show A7s degrading excessively for a race tire (with proper setup).  I have almost the exact same results with 10hc A7s as I do 10hc R7s.  If there is support for this then I’d advise R1S is in the same group.  I’ve had similar results with both tires but they did require exstensive set up changes.  Also Hoosier contingency is awesome and they do a great service to our community by offering it. 

Edited by Emag

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daytonars4

“Almost”... That’s not convincing Mr. 315’s. But happy to see you supporting the concept of a width mod. I’ve had A’s cord in 10 HC when R’s last 20+. Maybe I need you to setup my car 😜

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Emag
Just now, daytonars4 said:

“Almost”... That’s not convincing Mr. 315’s. But happy to see you supporting the concept of a width mod. I’ve had A’s cord in 10 HC when R’s last 20+. Maybe I need you to setup my car 😜

Is anyone really expecting to race competitively in GTS on 20hc tires?

Or are the ~10hc you get enough for a set of race tires (I believe it is). 

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Alan_Wolfe
21 hours ago, daytonars4 said:

Yes, that was the intended goal of the GTS rule set. To build however you want. As builds have progressed people with lesser budgets are being left out. 

 

Lawrence Gibson 

Midatlantic GTS2/ST3

 

 

How does the budget issue have anything to do with Hoosier tires?  Changing size is a couple % issue, and changing compound is next to nothing.  

In my admittedly atypical example, going up one tire size and switching to As increased my tire budget a whopping $12/set.

It's beginning to seem to me to be just a bunch of people whining about have to change - period.

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daytonars4
36 minutes ago, Alan_Wolfe said:

How does the budget issue have anything to do with Hoosier tires?  Changing size is a couple % issue, and changing compound is next to nothing.  

In my admittedly atypical example, going up one tire size and switching to As increased my tire budget a whopping $12/set.

It's beginning to seem to me to be just a bunch of people whining about have to change - period.

It’s not $12 a tire to go from having a stock panel e46 M that can fit 275’s to one that can run 315’s as Emag has done with a widebody kit. He has the data that proves his car is faster on 315’s than 275’s. These mods are simply an effort to reduce the gap that develops from that width advantage.

A vs R is not about the cost per tire. It’s a longevity cost. A’s are known to cord after 10 HC’s. R’s last 20+. The guys who are winning tires I’m sure don’t care. But it’s something that matters to the mid-pack guys. So giving them an additional mod is once again just an effort to allow them to close the gap a tad.

As I said when I made this proposal, this is not about me personally. I’m fine with no mod for A vs R. I’m also fine with no tire mod since my car has a body kit on it. But this is about trying to increase participation in the class. And one of the biggest deterrents I hear from not only new racers but even those in GTS currently is that it has become a tire war. And at some point you can’t keep ignoring the growth of the more restrictive ST classes compared to the decline of GTS. GTS is one of the only classes around that has no rules in regards to tires. It’s probably time for that to change, at least for the lower classes like GTS1-3. 

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jscheier

Against the tire compound regulation.

Against the tire size regulation.

 

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Alan_Wolfe
22 hours ago, daytonars4 said:

It’s not $12 a tire to go from having a stock panel e46 M that can fit 275’s to one that can run 315’s as Emag has done with a widebody kit. He has the data that proves his car is faster on 315’s than 275’s. These mods are simply an effort to reduce the gap that develops from that width advantage.

A vs R is not about the cost per tire. It’s a longevity cost. A’s are known to cord after 10 HC’s. R’s last 20+. The guys who are winning tires I’m sure don’t care. But it’s something that matters to the mid-pack guys. So giving them an additional mod is once again just an effort to allow them to close the gap a tad.

As I said when I made this proposal, this is not about me personally. I’m fine with no mod for A vs R. I’m also fine with no tire mod since my car has a body kit on it. But this is about trying to increase participation in the class. And one of the biggest deterrents I hear from not only new racers but even those in GTS currently is that it has become a tire war. And at some point you can’t keep ignoring the growth of the more restrictive ST classes compared to the decline of GTS. GTS is one of the only classes around that has no rules in regards to tires. It’s probably time for that to change, at least for the lower classes like GTS1-3. 

We made the wide tires fit with a sawzall and a set of universal fender flares.  If you can do the labor it costs less than 2 tires, and it's a one time cost.

Properly sized As properly setup and driven correctly do Not cord after 10 heat cycles.  Again, my atypical experience is I use the A7s in the Exact Same Rotation with Exactly the Same Number of Heat Cycles as I was using the R7s.

 

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Emag
4 hours ago, Alan_Wolfe said:

We made the wide tires fit with a sawzall and a set of universal fender flares.  If you can do the labor it costs less than 2 tires, and it's a one time cost.

Properly sized As properly setup and driven correctly do Not cord after 10 heat cycles.  Again, my atypical experience is I use the A7s in the Exact Same Rotation with Exactly the Same Number of Heat Cycles as I was using the R7s.

 

We’ve been through this.  The perception is that widebody is an expensive endevour and all we’re trying to do is alleviate the negative connotation that these modifications have to some racers.  Also, allow racers from more restrictive classes (ST) to race in GTS against purpose built GTS cars more competitively. 

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gofastzach
2 hours ago, Emag said:

We’ve been through this.  The perception is that widebody is an expensive endevour and all we’re trying to do is alleviate the negative connotation that these modifications have to some racers.  Also, allow racers from more restrictive classes (ST) to race in GTS against purpose built GTS cars more competitively. 

Against this rule for a few reasons.  No data exists that shows definitively that x-tire is faster that y. Only perception. Which has been the real source of the decline of gts. If I spend whatever money it takes to remove the flares on my car and narrow my wheels will more people show up to gts2? If they don’t do I get to complain the next year so the rules are written in my favor?  Fender flares can’t be the reason e36/e46 guys choose ST over gts because the majority of them have flares already. Pretty sure Matt W is the only who doest and is contemplating it for next year already. I went wide with my car to offset its inherent terminal velocity deficiency. The key there is it was my choice to do that just like it was emags choice to go wide vs go v8 like some in gts. At this point we need to get back on track with what will progress the class with input from people who actually show up and are committed to make the class better. 

Edited by gofastzach
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Alan_Wolfe
16 hours ago, Emag said:

We’ve been through this.  The perception is that widebody is an expensive endevour and all we’re trying to do is alleviate the negative connotation that these modifications have to some racers.  Also, allow racers from more restrictive classes (ST) to race in GTS against purpose built GTS cars more competitively. 

Rule making is done based on perception and negative connotation instead of facts???

If you are trying to get ST folks to participate then why is there a proposal to change GTS2 to 13.5 when ST5 is 14?

And are you going to harmonize the FWD adjustment to make crossing over easier for them?

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daytonars4
31 minutes ago, Alan_Wolfe said:

Rule making is done based on perception and negative connotation instead of facts???

If you are trying to get ST folks to participate then why is there a proposal to change GTS2 to 13.5 when ST5 is 14?

And are you going to harmonize the FWD adjustment to make crossing over easier for them?

You may not be aware. But Emag has multiple track records in GTS3. He has substantial data over the past couple years which shows the benefit of going to 315’s from 275’s. This is not just about perception. He has the data to back it up. Hence why he is willing to spot people on 275’s some power as a BOP for GTS3.

 

ST5 is not the natural crossover for GTS2. It is ST4 which is at 12. But the e36’s that have proven to be extremely competitive in ST4 are easily able to go from 12 to 13.5/14 for almost no cost ($20 restrictor plate.) Some in GTS2 would just like to reduce the amount of ballast they currently have to run so that’s the only real reason for that change. To be less weighted/detuned. 

 

The FWD adjustment is basically a TCR mod. TCR’s currently in ST get a 1.0 advantage which is absurd. This is simply an attempt to remove any FWD mod from GTS for factory built TCR’s so they don’t start dominating GTS as they have ST.

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Alan_Wolfe
23 hours ago, daytonars4 said:

You may not be aware. But Emag has multiple track records in GTS3. He has substantial data over the past couple years which shows the benefit of going to 315’s from 275’s. This is not just about perception. He has the data to back it up. Hence why he is willing to spot people on 275’s some power as a BOP for GTS3.

 

ST5 is not the natural crossover for GTS2. It is ST4 which is at 12. But the e36’s that have proven to be extremely competitive in ST4 are easily able to go from 12 to 13.5/14 for almost no cost ($20 restrictor plate.) Some in GTS2 would just like to reduce the amount of ballast they currently have to run so that’s the only real reason for that change. To be less weighted/detuned. 

 

The FWD adjustment is basically a TCR mod. TCR’s currently in ST get a 1.0 advantage which is absurd. This is simply an attempt to remove any FWD mod from GTS for factory built TCR’s so they don’t start dominating GTS as they have ST.

I'm not doing a good job of explaining my points.

I was referring to A7s vs R7s and the non-budget issue of switching.  Why are we restricting people's choices for items which have a zero or trivial budget impact?

The FWD adjustment I was referring to is the production car adjustment: 0.6 in ST vs 0.4 in GTS

Edited by Alan_Wolfe
misplaced .

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daytonars4
19 minutes ago, Alan_Wolfe said:

I'm not doing a good job of explaining my points.

I was referring to A7s vs R7s and the non-budget issue of switching.  Why are we restricting people's choices for items which have a zero or trivial budget impact?

The FWD adjustment I was referring to is the production car adjustment: 0.6 in ST vs 0.4 in GTS

Gotcha. Yea I think there's not much support for the R vs A compound mod.

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Alan_Wolfe

Two more questions, then I plan to shut-up.  I'm also getting tired of me posting.

How is the adjustment calculated for a staggered setup?

How is the adjustment calculated after a wet race for different sized wets than the tires used for the certification dyno?

 

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daytonars4
1 hour ago, Alan_Wolfe said:

Two more questions, then I plan to shut-up.  I'm also getting tired of me posting.

How is the adjustment calculated for a staggered setup?

How is the adjustment calculated after a wet race for different sized wets than the tires used for the certification dyno?

 

Conceptually if you have a 245 front and 315 rear then your mod would be based on 315's. If wets are 225 and drys are 275 then you would be submitting a compliance file for each. 1 wet file and 1 dry file. The dyno in theory shouldn't dramatically change based on tires so you don't necessarily need to do a completely different dyno for each. 

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dkslankard

For a staggered setup I would propose the average size of combined front and rear sizes. i.e. 255 front with 295 rear would be classed as 275s square setup. Weight bias in different cars or person set up choice may dictate staggered setup. Tire performance correlates to total tire width, averaging front and rear seems a fair way to go.

 

Keith Slankard

Rocky Mountain Region

GTS2 #44 moving to GTS3

 

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daytonars4
22 hours ago, dkslankard said:

For a staggered setup I would propose the average size of combined front and rear sizes. i.e. 255 front with 295 rear would be classed as 275s square setup. Weight bias in different cars or person set up choice may dictate staggered setup. Tire performance correlates to total tire width, averaging front and rear seems a fair way to go.

 

Keith Slankard

Rocky Mountain Region

GTS2 #44 moving to GTS3

 

I like your idea with 1 caveat. The Hoosier A/R7 255/35 18 is actually larger than the Hoosier 275/35 18. So if someone is running that specific 255/295 combo it should be treated as "over 275 avg" otherwise you are basically undermining the system. 

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jbrauer11

I do not support any tire rule changes at this time.

Josh Brauer
NASA RM GTS2

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rokkit

I support this and would like to see it implemented in some form or another. 

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jvanhouten

I do not support a mod for tire width/compound.

GTS has always been an open class and the last time we changed a rule based on "perception" we lost numbers and the same thing will happen here, I fear. We makes changes the disadvantage those that have invested in their cars and actually race with us in order to attract those that "say" they will race with us if we just make these changes, but then never do. We alienate those that have supported us and never get an increase in new racers to make up for it. 

The more we make the series like ST, the lesser the incentive to choose GTS over ST--people will just go where the numbers are. GTS had the attraction of an open rule set (with German cars) over the complication of ST--that was the appeal. We are steadily taking away the differentiation and our strength. I'd rather open the series to non-German cars than continue with the restrictions/modifiers.

John Van Houten
GTS4 - back in 2020.

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Michael G.

The Period of Proposals submissions is now closed.

Michael G

GTS Dir.

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