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Last Post 14 Jan 2001 05:50 PM by  NBM LS1 M6
Street-tire cars running with race-tire cars
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slowSER
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10 Jan 2001 06:50 AM
    This is something I've been thinking about for our local autox club for the 2001 season:

    Instead of lumping together all cars with street tires into a single "Street Tire Class," what about using a PAX so that cars with street tires can run in regular open classes?

    STS and STR can be used as the benchmark -- Those classes are identical except one is for street tires and one is for R-compound tires. The difference in the PAX for the two classes is .027 (.783 for STS, .810 for STR). To determine the street tire PAX for all the other clases, you'd just subtract .027 from the regular PAX. The SS-X PAX would be .803, the AS-X PAX would be .788, BS-X would be .785, and so on.

    So on a "power course" or "handling course," a BS Miata on street tires wouldn't be lumped in the same class as an ESP Mustang on street tires -- the Miata would use a multiplier of .785 and be PAXed against other BS Miatas (.812); and the Mustang (.822) would be PAXed against other ESP Mustangs (.798).

    Of course this applies to Stock and Street Prepared classes, which use R-compound tires -- I don't know how a PAX could be figured for Prepared and Mod classes.

    Thoughts?

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    Pat
    '93 Sentra SE-R, DSP/Tracktoy
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    Mr53CSP
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    10 Jan 2001 07:13 AM
    [b] There was too much math involved. =) In the Las Vegas region, we have a daily driver class that basically puts all the other street tired cars together (for those who wish to run in Daily Driver) and they are PAX against each other. Meaning, a CSP-DD car can be actively competing against a ESP-DD car. I think this is what you're going for...but, you threw too many numbers in the mix and it's early. [/b]

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    [b]-53 CSP
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    10 Jan 2001 09:35 AM
    [QUOTE]Originally posted by slowSER:
    [b]This is something I've been thinking about for our local autox club for the 2001 season:

    Instead of lumping together all cars with street tires into a single "Street Tire Class," what about using a PAX so that cars with street tires can run in regular open classes? . . . STS and STR can be used as the benchmark -- Those classes are identical except one is for street tires and one is for R-compound tires. The difference in the PAX for the two classes is .027 (.783 for STS, .810 for STR). To determine the street tire PAX for all the other clases, you'd just subtract .027 from the regular PAX. . . So on a "power course" or "handling course," a BS Miata on street tires wouldn't be lumped in the same class as an ESP Mustang on street tires. . . Of course this applies to Stock and Street Prepared classes, which use R-compound tires -- I don't know how a PAX could be figured for Prepared and Mod classes. Thoughts?
    [/b]


    I'm suspicious the math calculations wouldn't acheive their desired equality/parity result.

    I take it you have a local street tire class in your region, but only one for all cars with those cars indexed to their respective stock class. We also have a local street tire competition, but it is divided into two separate indexed classes entitled SK1 and SK2. The former covers AS, SS, and FS, while the latter designation covers the balance of the stock classes. In order to run in these classes, the car must meet stock SCCA Solo2 classing specifications.

    I take it from your query that you also would like to accommodate cars that would ordinarily run in Street Prepared so that they could run on street tires on an index within that class. I'm not sure the math would produce parity there either.

    There has been an extensiive discussion regarding the existence of local index street tire classes in our region, and that discussion flowed into a thread elsewhere in this forum. I can understand that such an accommodation might appeal to some, but it is also a judgement call how such special local classes might detract from the operation of the standard stock classes that correspond to SCCA national rules.

    BTW, I fail to see why anyone would want to drive a Prepared class car on street tires.

    In our own region, in addition to STS and STR, and the two stock street tire classes I have mentioned, we have a local "run what you brung" class that covers ANY production car with no limitations on engine or suspension modifications. The car must theoretically be street licensable. The rear seats may be removed, but the interior must be retained. There must be a minimum of two seats. Everyone runs based on a PAX of .870. It's more of a fun class than anything, but it covers street cars that have extensive modifications that would make the car illegal in Street Prepared. We are calling it Street Modified (SM), but the name will no doubt be changed next year to something else so as to avoid confusion with the SCCA national SM class.

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    Bob Hempy
    SoPac CSCC GRA
    SM #27
    NBM 1998 Z28 M6
    PGM 1995 Z28 A4

    [This message has been edited by NBM LS1 M6 (edited January 10, 2001).]
    Mr53CSP
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    10 Jan 2001 10:07 AM
    [i] BTW, I fail to see why anyone would want to drive a Prepared class car on street tires. [/i]
    [b] Well, I bought a '89 Honda CRX in the first part of 99. I began autoXing in the summer of 99...basically as is when i bought it (except adding sway-bars). I didn't have another set of rims or the money to buy new tires...so i ran with street tires until i could afford race tires (last week =)). I'm sure there are several people who can relate to this. That's why they run street tires in Street Prepared. And, out of an average of 70 competitors, i was consistently (as time improved) in the top 20. This is pretty good considering i was on Nitto 450s with a threadwear of 300 and a car that got to 1320' from a stand still in 16.1secs. I was the fastest on street tires every event, except one. I'm not saying running on street tires is smart or the best way to compete...but, sometimes, it's affordable.

    About classing them all the same. AutoX is suppose to be the introduction to road racing. It's suppose to be fun, yet technical. It lets you wring out the most of your street driven or modified trailer queens. I don't mind being classed similarly to a Mustang Cobra (ESP) while driving my CRX (CSP) while in a street tire class, I'm out to have fun. This is slightly different. I think people who buy race tires and such are out to compete. People who run on street tires are there to enjoy themselves...but, with a competitive environment making it more interesting So, what did mean in all this...

    eh, let the street tire guys run all together. PAX the street tire guys according to what their class would be. It may not be completely equal...but, close enough to make enough people smile. And that's what it's all about.[/b]

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    [b]-53 CSP
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    Mark Hirt
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    10 Jan 2001 10:17 AM
    Most clubs/regions just lump all the street tire cars into one class (we use ST) and score that class on index. In the computer a driver in ES Street tire is classes as ST-ES and indexed with the ES number.

    Creating an accurate index number (PAX or RTP) for street tired cars is a crap shoot at best. So much depends on tire quality and different cars will probably react differently to the race/street rubber. When we came up with the STS/STR number for the RTP a couple years back we guessed (we did have some good data) street that tires made about a 1.5 second difference on a 40 second course. Locally we had two drivers of fairly equal talent driving the same car, not THE same but same make model. Their times were almost always in the 1.5 to 2 second range so we set the STS and STR number at 1.6 seconds, crossed our fingers and prayed. At the beginning of the year the top two STS drivers in our area were doing quite well, good enough that people complained the index number was too easy. Later in the year when the weather got warmer they started to fade. See on a 40 degree day it seams a shaved Yokohama 520 will out stick a BFG, Hoosier or Kumho especially on a well prepared STS car.

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    [url="http://sites.netscape.net/hirtmark/"]Mark Hirt[/URL]
    2000 Totyota Celica GT
    thedoc
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    10 Jan 2001 11:09 AM
    [QUOTE]Originally posted by slowSER:
    [b]Instead of lumping together all cars with street tires into a single "Street Tire Class," what about using a PAX so that cars with street tires can run in regular open classes?[/b]


    Hmmm... The sentiment is nice, but the follow-through is far too complex and unreliable.

    There is no reason why a car with street tires can't run in the regular class. As long as the car meets the rules, it's fine. Now as far as being competitive, not likely.

    Here's my thought: WAH.

    Solo II rules already break down the classes to a very low level. Sometime I almost think too low, not many competitors. At national-level events, the classes are definitely justifiable, though.

    If you look around at some other motorsports, you'll probably feel spoiled. Rally only has a handful of classes. For the people with serious mods, you gave Group 2 (small engines + 2WD), Group 5 (big engines + 2WD) and Open (all 4WD). I you wanna run your Subaru Justy, you are going to have to play with the Imprezzas and Hyundais. WAH.

    If you don't want to spend the time AND money that it takes to make your car and yourself the best possible, do you really deserve to win? Why should there be an index on tires? For that matter, different kinds of tires? Should we subdivide classes with indexes on particular models and options? What's the index for an automatic transmission, or a worn-out slipping clutch? What's the index on driver experience? Where should it stop?

    Even the PAX system, based on thousands of data points, isn't 100% even.

    If you know you don't have the right equipment to win, you can either obtain it, put up with not winning, or move on.

    "If I play with my calculator long enough, I can prove I'm faster than you!" SCCAForums Image


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    Michael McAvoy - 1990 Supra Turbo
    NHA Hillclimbs OSPO Class
    SCCA Solo II "Ill-Prepared"
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    www.premier1.net/~thedoc[/URL]
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    NBM LS1 M6
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    10 Jan 2001 11:20 AM
    [QUOTE]Originally posted by Mr53CSP:
    [b]. . . Well, I bought a '89 Honda CRX in the first part of 99. I began autoXing in the summer of 99...basically as is when i bought it (except adding sway-bars). I didn't have another set of rims or the money to buy new tires...so i ran with street tires until i could afford race tires (last week =)). I'm sure there are several people who can relate to this. That's why they run street tires in Street Prepared. . . . About classing them all the same. AutoX is suppose to be the introduction to road racing.
    [/b]


    I understand the first part. I did the same thing. I ran in ESP on street tires until I had extra wheels and had acquired Kumhos for them.

    However, I was referring to the scenario where someone would purposely built a "Prepared" class car and purposely run on street tires. You will notice I didn't day "Street Prepared." OTOH, if one reads the SCCA rulebook, one can understand how the slightest modification, if it the "wrong one," can throw one's nearly stock street car into a Prepared or Modified class. The case in point is the triangulated subframe connectors that MANY Camaro and Firebird owners have installed on their cars as the first modification they made after buying the car new.

    BTW. . . where in the SCCA Solo rulebook does it imply that autox is **supposed** to be an introduction to road racing? Many of us see it as a stand alone sport in itself, and not some primer for road racing.

    Also, the SCCA Solo rulebook doesn't refer to Kumhos, etc., as race tires. They are DOT tires, and therefore street legal until the corresponding street legal treadwear guidelines are exceeded. The word "race" doesn't occur within the realm of SCCA Solo2 competition. Therefore, in what way is autox intended by SCCA to be a primer for road racing?

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    Bob Hempy
    SoPac CSCC GRA
    SM #27
    NBM 1998 Z28 M6
    PGM 1995 Z28 A4

    [This message has been edited by NBM LS1 M6 (edited January 10, 2001).]
    Mr53CSP
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    10 Jan 2001 02:54 PM
    [b] I'm not saying it's officially the Prep Auto Sport to road racing. I just know that anyone who takes AutoXing as a formal competitive sport tends to do other events, such as Solo 1 and Club racing. I am personally very happy do AutoX for the time being, but, i hope to move to a more commercialized form of racing where bumping fenders is much more possible. I love autoXing, but, one event of wheel-to-wheel "Racing" has given me a fonder desire to do more than just AutoX.

    And Kumho's are DOT tires? So i could still run (technically) in a "street-tired" class? CSP-DD is MINE!! =)

    That would be kinda silly to build a street-prepared car just to run on street tires though... maybe the driver would be trying to overcome the underdog status? ie. taking the 17sec Civic and doing 11s. If a guy could take TTOD with a street-tired car...it has to mean something: either the rest of the entrants suck (for the lack of a better word) or he's an extremely good driver. [/b]

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    [b]-53 CSP
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    Mark Hirt
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    10 Jan 2001 04:26 PM
    NBM LS1 M6: I know you want your sub-frame connectors. One of the reasons you should not want them is... While they don't do that much in a Camaro and Firebird they do help Mustangs A LOT.

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    [url="http://sites.netscape.net/hirtmark/"]Mark Hirt[/URL]
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    Davard
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    10 Jan 2001 11:49 PM
    [QUOTE]Originally posted by Mr53CSP:
    [b]And Kumho's are DOT tires? So i could still run (technically) in a "street-tired" class? CSP-DD is MINE!! =) [/b]


    The DOT on the Kumhos means that they are street-legal. Most street tire classes have minimum treadwear ratings, usually 140 or higher. Kumhos have a treadwear around 50 or less.

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    David Avard
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    11 Jan 2001 11:34 AM
    [QUOTE]Originally posted by NBM LS1 M6:
    [b]However, I was referring to the scenario where someone would purposely built a "Prepared" class car and purposely run on street tires. You will notice I didn't day "Street Prepared." OTOH, if one reads the SCCA rulebook, one can understand how the slightest modification, if it the "wrong one," can throw one's nearly stock street car into a Prepared or Modified class.[/b]


    This is rather silly, I think. Why would anyone want to intentially built a street-tired Prepared Class car? Building such a car will be an involved and expensive project, and when done to the extent of the rules, not really street legal. Since wheels are usually not stock sizes, new tires will need to be purchased. When it comes to that, Treadwear 140 DOT tires - or slicks.
    Hmmmm...!

    As far as someone running in prepared because of small mods kicking them out of another group, oh, well... An otherwise stock Camaro with subframes won't likely keep up with a truly Prepared-Class car no matter the tires. Most often, these people are pretty novice anyway, not likely to be truly competitive drivers yet. Why bother trying to account for it?

    My Supra started out to be a Group 5 Rally car, purchased for that goal. Unfortunately, it has been sidetracked, and is now an NHA OSPO-Class hillclimber. Did awesome in two events this year, although it got bent at the latter. The goals of this class are almost totally incompatible with and SCCA Solo II class, but it fits best in Prepared. How well does it do? See my sig. SCCAForums Image


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    Michael McAvoy - 1990 Supra Turbo
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    11 Jan 2001 01:18 PM
    [QUOTE]Originally posted by thedoc:
    [b] This is rather silly, I think. Why would anyone want to intentially built a street-tired Prepared Class car? [/b]


    I think you misunderstood my point. That was my point, to wit, no one **would** purposely build a Prepared class car and then run it on street tires. SCCAForums Image

    The original direction of this thread was about indexing cars on street tires so that they could run in their respective standard SCCA national class against similar cars on DOT tires, and I suggested that the math would be too complicated. I further suggested that we had accommodated this issue by setting up two local street tire classes, one for cars running in AS, SS, and FS, and the other for the balance of the Stock classes.
    Then--the confusion--I suggested that further diluting the regular SCCA national classes by having separate indexed street tire **classes** for Street Prepared class cars was too much. One of the complaints--discussed in another thread on these boards--is the notion that the very existence of local indexed street tire classes dilutes the number of participants in the regular SCCA Stock classes (classes where DOT tires are the rule rather than the exception to be competitive).

    [QUOTE][b] As far as someone running in prepared because of small mods kicking them out of another group, oh, well... An otherwise stock Camaro with subframes won't likely keep up with a truly Prepared-Class car no matter the tires. Most often, these people are pretty novice anyway, not likely to be truly competitive drivers yet. Why bother trying to account for it? [/b]

    My point is the fact that many of us came to SCCA autox events the first time with our
    cars **already** setup with those minor suspension modifications. We were not fully
    aware of the SCCA rules before we decided to take up autox events. SCCAForums Image

    There is a trade-off involved. Some of us are on limited budgets. Having an all around
    high performance toy is fun. Demodding and/or trading the car for a similar car so as to
    run that car legally in a Stock or SP class is a financial decision. In the long run, with planning, maybe some of us can keep our toys and eventually, in addition, buy a car
    specifically to run in a Stock class. That is my long range plan. In the meantime, trading
    a car can sometimes mean losing one's financial shirt. SCCAForums Image

    Besides, it is my observation that, driving skills being equal, i.e. if I had national class driving skills, I would be within a second or two of the BSP Corvettes driven by the national champion drivers in my local SM class. So. . . while I am learning to drive, I have decided to drive my highly undermatched Z28 in our local "run what ya brung" any thing goes class we call SM. SCCAForums Image

    Bob Hempy
    CSCC Solo2 E-Board Secretary
    NBM '98 Z28 M6 (autox car)
    PGM '95 Z28 A4 (grocery getter)

    [This message has been edited by NBM LS1 M6 (edited January 11, 2001).]
    Patrick Washburn
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    14 Jan 2001 04:19 PM
    Mr53CSP Wrote:
    'm not saying it's officially the Prep Auto Sport to road racing. I just know that anyone
    who takes AutoXing as a formal competitive sport tends to do other events, such as Solo
    1 and Club racing.

    You haven't been to Nationals yet, have you? I disagree with this sentiment, as well as any implication whatsoever that Solo is some sort of introduction to road racing, or is somehow a "lesser" sport. Two completely and distinctly different sports with different skill sets. I happen to know *many* soloists who are serious enough to invest thousands of dollers and many weeks of time every year for nothing more than Solo trophies. Most serious national class competitors that I know don't do any other forms of motorsport.

    Not to jump on you or anything, but I think it's wrong to imply that AX is some sort of "training" series for real racing.

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    Patrick Washburn
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    14 Jan 2001 05:50 PM
    [QUOTE]Originally posted by Patrick Washburn:
    [b] You haven't been to Nationals yet, have you? I disagree with this sentiment, as well as any implication whatsoever that Solo is some sort of introduction to road racing, or is somehow a "lesser" sport. Two completely and distinctly different sports with different skill sets. I happen to know *many* soloists who are serious enough to invest thousands of dollers and many weeks of time every year for nothing more than Solo trophies. Most serious national class competitors that I know don't do any other forms of motorsport.

    Not to jump on you or anything, but I think it's wrong to imply that AX is some sort of "training" series for real racing.
    [/b]


    My sentiments exactly. FWIW, I happen to know one **serious** autox only competitor--who BTW placed second at nationals in a stock class last Fall--who drives or tows her husband's daily driver to events. This is the car in which she placed second at Topeka last Fall.



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    Bob Hempy
    SoPac Cal Club GRA
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    PGM 1995 Z28 A4 (grocery getter)
    NBM 1998 Z28 M6 (autox car)
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