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Author Topic: Best Tire and wheel options for Autocross  (Read 1571 times)

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Offline SilverGXP

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Best Tire and wheel options for Autocross
« on: August 13, 2019, 08:05:35 PM »
Hello,  my son and I recently purchased a 2008 Solstice GXP.  We intend to use it to run some autocross events in a stock class.  The rules require a stock rim width, but do allow up to 1 inch change in wheel diameter and up to 7mm change in offset.  I have seen some articles recommending a smaller wheel diameter to save rotational weight.  Any recommendations on the best wheel/tire set up?

Offline elff

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Re: Best Tire and wheel options for Autocross
« Reply #1 on: August 13, 2019, 08:43:04 PM »
if stock class, then your best option is as light a rim that you can find in the stock size of 18x8"
Then put on the biggest Hoosiers R-Comps that fit in your wheel wells.

It's actually one of the dumbest things, but according to the rules.  RACE rubber is consider OK for stock.
So if you don't run it, you are not competitive to those that do.


Offline Steelmesh

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Re: Best Tire and wheel options for Autocross
« Reply #2 on: August 14, 2019, 01:43:59 PM »
Hello,  my son and I recently purchased a 2008 Solstice GXP.  We intend to use it to run some autocross events in a stock class.  The rules require a stock rim width, but do allow up to 1 inch change in wheel diameter and up to 7mm change in offset.  I have seen some articles recommending a smaller wheel diameter to save rotational weight.  Any recommendations on the best wheel/tire set up?

Welcome!  Are you guys experienced with autocross?  I'll be at the Aug 25th Toledo airport race, might be in the Cruze Missile though
2006 Solstice #1458, Twincharged LE5/LEA, 5757+M62, Werks exh manifold, Tial bpv/wg, Cams, dual meth, 40 PSI, Kappadapt clutch hose/flywheel bolts/trans mount, Aisin AR5, Stage 5 clutch
Turbo-only power 444whp/422wtrq

2013 Cruze Missile, tuned, 42 lb, ZZP SRI/FMIC/DP/MP/CB, Kappadapt trans mount

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Offline wspohn

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Re: Best Tire and wheel options for Autocross
« Reply #3 on: August 14, 2019, 02:40:25 PM »
It's actually one of the dumbest things, but according to the rules.  RACE rubber is consider OK for stock.
So if you don't run it, you are not competitive to those that do.

Agree.  If it were a streetable tire that was required, the Bridgestone Potenza RE-71R are long time faves. Wear rating is 200 which is low for a street tire but some guys use them for both and just change them whenever they wear out.

This test is about 3 years old, but not sure how much has changed in the mean time  https://www.tirerack.com/tires/tests/chartDisplay.jsp?ttid=202&affiliate=HJ7
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Offline SilverGXP

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Re: Best Tire and wheel options for Autocross
« Reply #4 on: August 14, 2019, 09:13:25 PM »
Thank you for the tips and reference, always like to see test data.  I will check out the Hoosiers and the Bridgestones.  We are pretty new to autocross, so it will take us a while to get competitive from a driving standpoint.  Appreciate the advice, will look for some light wheels in stock size.

Offline 4Flattires

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Re: Best Tire and wheel options for Autocross
« Reply #5 on: August 24, 2019, 07:52:23 AM »
if stock class, then your best option is as light a rim that you can find in the stock size of 18x8"
Then put on the biggest Hoosiers R-Comps that fit in your wheel wells.

It's actually one of the dumbest things, but according to the rules.  RACE rubber is consider OK for stock.
So if you don't run it, you are not competitive to those that do.

Hi everybody.  I have been autocrossing in SCCA for 10 years now.  About 5 years ago SCCA all but did away with the "Stock" classes in favor of the newer "Street" classes.  The native class for a GXP is now A Street, which requires a 200 treadwear tire.  The Bridgestone RE-71R is most driver's choice.  The BF Goodrich g-Force Rival is less common but similarly capable.  Falken RT615K+ are used in the Spec Coupe class, which is only for that pair of cars by Subaru and Toyota (FRS and the other one that is basically the same).

Seat time is the Number 1 performance modification.  Tires are Number 2.

Steve
Autocrossing a Sky Redline this year

Offline elff

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Re: Best Tire and wheel options for Autocross
« Reply #6 on: August 24, 2019, 01:55:07 PM »
all but did away with the "Stock" classes

Can you clarify this statement, because this makes it sounds like they still exist

Offline scanner

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Re: Best Tire and wheel options for Autocross
« Reply #7 on: August 24, 2019, 07:53:39 PM »
I'm running C-Street this year per new SCCA rules with Bridgestone Potenza RE-71R and Axis Sport XQ lighter wheel.  Solo exhaust also helps the breathing.  I still can't decide between all traction off or performance.   It seems to depend on my mood and the course...

Clear Skies!
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Offline elff

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Re: Best Tire and wheel options for Autocross
« Reply #8 on: August 25, 2019, 08:18:30 AM »
Competitive mode always worked really well for me. 

Offline 4Flattires

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Re: Best Tire and wheel options for Autocross
« Reply #9 on: November 09, 2019, 05:47:57 PM »
I wrote:  "all but did away with the "Stock" classes"

Can you clarify this statement, because this makes it sounds like they still exist

Sure!  There is still Super Street-R.  The following cars remain eligible to compete on R compound tires:

Alfa Romeo
4C (2015-16)
Audi
TT RS (2012-13)
BMW
M3 & M4 (F80/F82 chassis)
(2015-17)
Cadillac
XLR
Chevrolet
Camaro SS 1LE (V8) (2017)
Camaro Z28 (2014-15)
Camaro ZL1 (2012-15, 2017)
Corvette (C6, non-ZR1) (2005-13)
Corvette Grand Sport (C7) (2017-
19)
Corvette Stingray (C7) (2014)
Corvette Z06 (C5) (2001-04)
Dodge & SRT
Viper & Viper GTS (non-ACR,
non-TA) (2013-17)
Viper (non-ACR) (2008-10)
Viper SRT-10 (2003-07)
Viper GTS (1996-2005)
Viper R/T (1992-2003)
Ford
Mustang Boss 302 Laguna Seca
(2012-13)
Mustang Shelby GT350 &
GT350R (2015-16)
Mustang Shelby GT500 (2007-15)
Jaguar
F-Type (non-Project 7) (2014-16)
Lotus
Elise (non-SC) (2005-11) (see Appendix F)
Evora S (2011-14)
Exige (non-S) (2006)
Mercedes-Benz
AMG (NOC)
Porsche
718 (all) (2017-19)
911 (991 chassis; non-R, nonTurbo, non-Turbo S, non-GT2,
non-GT3) (2015-17)
911 (991 chassis; non-GT3)
(2012-14)
911 (997 chassis)
911 GT3 (997 chassis, non-RS)
911 GT3 (996 chassis)
911 Turbo (930 chassis) (1974-89)
Boxster (all, incl. Spyder) (1998-
2016)
Cayman (all, incl. R; excl. Clubsport) (2006-16)
Boxster S (2009-14)
Boxster Spyder (2011-12)
Cayman GT4 (non-Clubsport)
(2016)
Cayman R (2012)
Cayman S (2009-14)
Tesla Motors
Roadster (all) (2008-13)

 

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