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kc77 · Joined: 26 Nov 2003 Posts: 23 Location: Kansas City

I need a starting point to fill my 14 inch Kumho Victoracer slicks with air.
I'm running autocross for the second time this March (Kansas City SCCA) and I would like to know what PSI you run similar tires/wheels at.

thanks for the info and if anyone else has any tips on autoX or optimizing my NA 924 on the cheap it would be greatly appreciated.

mark

924RACR · Posted: Thu Feb 05, 2004 12:31 am Post subject:

For road-racing, we typically will run these around 32psi cold, believe it or not - target is actually to have them at around 39psi hot. At least, that's true for the Hoosiers. However, you might need more pressure for autox. Hopefully there's someone out there actually autox-ing on them who can say...
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jjadczak · Joined: 03 Jan 2003 Posts: 346 Location: Accokeek, MD

We run Hankooks and have found pretty much the same. I'd maybe start up with 34PSI though because your run is such a short one not enough time to build heat in tires (IMO). I agree with Vaughan, everyone I've talked to and with our limited exp. we've learned that 39-40PSI is the ideal number to get. Make sure you have someone take your tire pressure immediately after you finish your run. This is critical especially if your not running the same course all the time like we do. See we know where to start with PSI now because we've run the same courses a couple of times. You don't have that luxury in auto cross. Have fun! We did it one time when we got our first car together just to see if the thing worked. Boy did we learn a lot very quickly!! It does take a toll on the car though but it was fun.

Jeremy

ryoji · Joined: 10 Oct 2003 Posts: 168 Location: NNJ

Recommended pressure from Kumho is 35-40 psi. Most of light cars (<#2400) uses 35psi side. I heard lots of comment "give away" when it is over 40 psi hot. I heard most autoXers use 37+.

The good drivers, commonly said, use higher side of recommended pressure for R-comp. DOT Comp tires in both AutoX and Track. I guess that shows why Jeremy used higher pressure than I did last time.
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jjadczak · Joined: 03 Jan 2003 Posts: 346 Location: Accokeek, MD

Keep in mind Ryogi, that Ray and I have had a lot more track time at Summit than you. But we've been all over the place and learned a lot about under inflation and over inflation.b Now that we sort of know what were doing were always going to try to hit 39 to 40 PSI on the Hankooks.

Jeremy

ryoji · Joined: 10 Oct 2003 Posts: 168 Location: NNJ

The following links give you better idea of R-compound comp tire like yours. It shuld be better than my words.

http://www.redlinerennsport.com/DrEdEd14RTires1.html
http://www.redlinerennsport.com/DrEdEd15RTires2.html

As long as you have the tire pressure in the manufacture's recommended range, you do not have any problem for a while, until you want to change some susp. set-up.
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R.I.P.:a 924 ITA race car

kc77 · Joined: 26 Nov 2003 Posts: 23 Location: Kansas City

that's about what i thought. the guy i got them from ran
them 32-36 on an MR2 so the 30's make sense. I'll make adjustments from there.
thanks for the input

mark