Street tires in IT??

[pfcs]

why not simplify it to "Run street tires of 180TW or higher in IT using existing rules and classifications"?

if it's popular, you have people to run with. what you're proposing seems like an awful lot of work, not to mention weight reductions are not always achievable. ITA cars in your system need to loose 20% of their ITCS weight if on street tires. that's 200# for every 1000# of ITCS weight. few if any cars will be able to do that. and you didn't even include ITB, a class you used ot run and know is popular in your area, and one of the more cost sensitive classes, too. What you've made is effectively equalized ITS/R with compensation for tires.

I don't get it.

Time to build a New Beetle!

[Flyinglizard]

great start, great idea.

FWIW there is not a lot of lap time difference of the non Hoosier tires in the 40-140 TW value range. The Toyo R 1 can be very close to the Hoosier on some cars. heavy, High power/ or over driven.
I think that you are wasting your effort trying to correct the tires in the 40-140 range. Just do 180 or not.
Add 100# for not and subtract 100# for 180. The Hoosier will still cover the weight IMHE
data follows
After running the same cars( Golf HP, Jetta Turbo, 99 SM) on R1,R6 and Dunlop DZ1 and DZ101;
The Hoosier to 180 + will be about 3-4 sec per lap @ 2:30 laps , like WGI or Sebring, RAlanta.

It takes around 100#added to slow one second for Sebring and WGI under 250HP/sedan.
So I get about 1.5 sec advantage Hoosier @ 200# weight spread. ( a little less @ Sebring a maybe a little more @ WGI, due to speed range)

Maybe consider backing off the throttle stop on the faster car until you die laughing form the drafting battles.

I would consider double dipping the cars the other way. IE spec @ 180+ and let them also run the IT group with whatever tires that they have. The 180 Tires may go as far as 3000 race miles @ 120$ per tire for many cars. Many SCCA guys could run two years on these tires with careful management, IMHO.

[lateapex911]

OK, so lets run a scenario.

Your RX-8 will race with the highest deduction for TW 131 and up at a weight of 3005.
And your buddy, on the same tires will race at a weight of 2465.

Assuming that car can get that low, thats a 540 pound difference. FIVE HUNDRED and FORTY pounds.

Now, I know that an ITS RX-7 puts out about 185, and the RX-8 about 214, in IT trim.
So, thats about 30HP more to move the 540 extra pounds.

The RX-8 DOES get 1" wider rims, but.....

My quick sniff test tells me the RX-7 will win at 99% of the tracks.

You've taken the idea, and folded in a cross class equalization. While I admire the concept, it really cubes the difficulty of the concept.

Equalizing withing the class for tires of say 180 is hard enough, but adding multiple levels of tire factoring and THEN adding class equalization is reeeeeeeaaaly hard.

How did you come up with your factors??

[StephenB]

I tried to use what works for NASA. They use weight as an equalizer. Going from memory I think it equals about 170lbs difference. What they don't include is a factor for different weights of different cars. I figured a % factor would be easier and account for a car that weight is 2400lbs vs 3000lbs. Obviously 150lbs wouldn't affect both those cases the same.

I think what makes it seem complicated is adding the layer of combining ITR with ITS. I get that, honestly if it worked easily they wouldn't have ever created ITR.

I don't see a bunch of people buying tires for next weekend and probably not even for next year. In my class (ITR) I don't see any interest in using street tires, they have the money to keep doing what they are. Sooo.... a few NER ITS cars see already racing in STL. I am trying to equalize my car with them so that I can race with them. Maybe if I can demonstrate that racing on street tires can still be fun more people will join in and interest will build. At that time I wouldn't mind just racing other ITR cars. What I don't want to do is just race all alone on street tires in STU.

I hope this helps make more sense.


My personal goal: I will most likely be the only one in street tires and I will try to stay up with the double dipping ITS cars!

[mossaidis]

I agree with Jake. Large variances in minimum weights just to create equity within ONE street class complicates the issues since many cars will NOT be able to make the new minimum weight.

Option 1 would be to keep it simple, allow cars to run within their own class at the ITCS weight, provide separate prizes for running street tires.

Option 2 run with the NASA prescribed mins you mentioned above so that everyone runs in one class.

Possible option 3 would be to run multiple street class configuration by allowing street tire IT cars to run at lower class at a new minimum weight (or same minimum weight) OR allow them to run in the same class but at a new calculated min weight based on a standard weight deduction based on originating class. Driver's choice. If the region allow this, we can run multi-street classes with IT classes. If the region does not allow this, run multi-street classes within STL/STU or within ITE and be done with it.

ok... I am in Quebec City. Time to get my drink back on.

[Flyinglizard]

looking at the results.
180 Street tires on the ITB cars runs about the same as the ITC cars.
My Low level SM/ITA runs about the same as the ITB class.

[Bill Miller]

looking at the results.
180 Street tires on the ITB cars runs about the same as the ITC cars.
My Low level SM/ITA runs about the same as the ITB class.

Given that, is it a reasonable first approximation to say that an IT car would just run a class 'lower' if it runs a TW 180 or greater tire? For example, Stephen's ITR RX8 would run as an ITS car if it had TW 180 tires, and his buddy's ITS RX7 would run as an ITA car w/ the same tires.

And Stephen, I think it's great that you put so much thought, time, and effort into your idea, but I have to agree w/ Jake, I think you've over-complicated it.

As far as how to go about implementing something like this, I would imagine that if you could get enough folks that wanted to double-dip, you might be able to get a separate group added to one of the lower-subscribed run groups in your Region. I'm by no means suggesting adding an extra run group at this time, as that cuts into everybody's track time, and only benefits the double-dippers. But, if there's 'room' in another run group, why not? This is just something that popped into my head, so I haven't totally thought it through to determine the problems w/ it. I would say, that you would have to limit entries to those IT cars that were running street tires (TW 180+), otherwise you'd run the risk of lots of the IT cars wanting to double-dip, and over-subscribing that group. In other words, no ITS cars running Hoosiers going heads up against ITR cars on street tires.

[Xian]

I think the "class lower" thing is pretty darn close. The Hong Norrth MX3's would be an ITA car (if they existed with the 1.8 liter engine) and run around ITB times on street tires.

[StephenB]

Great feedback guys. I don't think it's worth 14+% weight penalty for an ITR car, that is the amount need to change an itr car to its with the current IT classification system used by the ITAC. Probably closer to the 8% I was thinking but who knows to be honest! I wish I could afford the track time and tire bill to get the info we are looking for to get this perfect but I will keep gathering data and sharing it

Stephen

[pfcs]

A possible problem with going one class lower is the distorted "ballistics"
An ITR car on street rubber is still going to accelerate like hell before slowing way down for turns.
Reminiscent of when SSA Camaros ran in ITB race groups. The lap times were nearly identical but re-passing the Camaro at the end of the Glenn's main straight (before bus stop existed) was a little more scary than how he passed me at the beginning! And it was required every lap if you wanted to keep up.

[Bill Miller]

A possible problem with going one class lower is the distorted "ballistics"
An ITR car on street rubber is still going to accelerate like hell before slowing way down for turns.
Reminiscent of when SSA Camaros ran in ITB race groups. The lap times were nearly identical but re-passing the Camaro at the end of the Glenn's main straight (before bus stop existed) was a little more scary than how he passed me at the beginning! And it was required every lap if you wanted to keep up.

I don't think there's that much of a disparity now Phil. You don't necessarily see ITR cars walking ITS cars out of corners now. So I don't think the old SSA / ITB comparison is valid, especially given that we're talking what, 15 years ago at least.

I'd say you can look at lap records, or fastest laps for each class for a given race weekend, to get a reasonable gauge if the 'class lower' concept is valid. It would certainly be easy enough to test via gentleman's agreement w/ an extra set of wheels and a set of street tires. It should be easy enough to distinguish those cars too, just add an "S" (for street tires) after the class designation (e.g. and ITR car running in ITS on street tires would have their class designation be ITRS, and subsequently ITSS, ITAS, and ITBS for the other respective classes). Unfortunately, the ones that get the short end of the stick are the ITC folks.

[lateapex911]

I don't think there's that much of a disparity now Phil. You don't necessarily see ITR cars walking ITS cars out of corners now. So I don't think the old SSA / ITB comparison is valid, especially given that we're talking what, 15 years ago at least.

I'd say you can look at lap records, or fastest laps for each class for a given race weekend, to get a reasonable gauge if the 'class lower' concept is valid. It would certainly be easy enough to test via gentleman's agreement w/ an extra set of wheels and a set of street tires. It should be easy enough to distinguish those cars too, just add an "S" (for street tires) after the class designation (e.g. and ITR car running in ITS on street tires would have their class designation be ITRS, and subsequently ITSS, ITAS, and ITBs for the other respective classes). Unfortunately, the ones that get the short end of the stick are the ITC folks.

I'd go lower case, for, you know, better reads.

I'm not losing too much sleep over ITC at this point.
(Certainly, at some tracks, their lap times won't be nearly as affected as higher class cars. They are easy flat through much of Lime Rock, and if the Street tires have lower rolling resistance, they benefit there. On the flip side, a major issue for them will be unsprung weight. it's more complicated than just the compound)

[Bill Miller]

I'd go lower case, for, you know, better reads.

I'm not losing too much sleep over ITC at this point.
(Certainly, at some tracks, their lap times won't be nearly as affected as higher class cars. They are easy flat through much of Lime Rock, and if the Street tires have lower rolling resistance, they benefit there. On the flip side, a major issue for them will be unsprung weight. it's more complicated than just the compound)

Lower case (or a different size) may make it easier to read.

I think you missed my point about ITC Jake. ITC doesn't have the option of going a class lower if they run street tires. But then again, I don't think an ITC Rabbit or 510 wears out a set of R6's like an ITS RX7 or an ITR BMW.

[Flyinglizard]

FWIW there are no 180TW tires in 13in. The ITC cars would have to go to 14 or 15s and the result would be a lot slower than my data.

My times were taken all with the same roll out, or Inches Per Revolution (IPR).
Even if the ITC cars made gearchanges to match prior IPR, they wil still be slower with larger tires.

[quadzjr]

Bring back ITD! Then ITC cars can run street tires against a slower class.. but then what about ITD? racing against horse drawn buggies?

[Knestis]

The "one class lower" idea wasn't quite right for the "E" (endurance) classes we saw at the Devil in the Dark this year, but those were "collapsed" classes with broader performance distributions. I wouldn't be at all surprised if within the existing IT category a one-class drop for street tires would be about right.

Kirk (who means on a REGION-BY-REGION basis, not as something to be implemented in the ITCS nationwide at this point)

[Chip42]

means on a REGION-BY-REGION basis, not as something to be implemented in the ITCS nationwide at this point

Don't worry about that!!

I've got some Rivals on order for my B car. I'll be testing at Roebling here soon, and racing at Sebring and Roebling in the near future. yes, partly this will be first time back out for the car since being rearranged by a mustang in February, but it should be a good test anyhow as I will have used but still good hohos to use, too.

I don't think I like the class lower drop. I see enough class overlap anyhow that it shouldn't matter. Race on street rubber, race within a group doing likewise and have fun. isn't that the point?

[Bill Miller]

I don't think I like the class lower drop. I see enough class overlap anyhow that it shouldn't matter. Race on street rubber, race within a group doing likewise and have fun. isn't that the point?

I think it's more about proof of concept and and easy implementation at this point Chip. As I said, I kind of threw the 'one class drop' concept out there as a straw man based on some of the other comments.

It certainly would offer a pretty easy double-dip potential (provided the adjacent classes run in different groups). I think it will be tough to squeeze an extra group into an already packed schedule (at least from what I remember in the NE).

/edit Think of it as something like the limited prep / full prep concept in Prod. And before anybody gets all up in arms, I'm simply saying that you can have cars that could be faster, racing in lower classes, by virtue of differences in the prep rules. Not really that much different than running a higher grunt car on lower performing tires, against a lower grunt car on stickier rubber.

[ShelbyRacer]

Chip-

Buy a 2nd set and let me shave 'em. Test those too. Let's see how deep the "cost savings" actually are.

And before anyone says "no shaving"- send me a set of worn tires and a set of new ones. I'll send you back two sets that you won't be able to tell apart *visually*.

[Knestis]

I'm pretty confident that you're going to be disappointed in the difference between shaved (or "worn") street tires and new ones, with the current crop of options. That's just one guy's pointing at the fence, tho.

K