solo2racer

I've run quite a few different tires during my 5 years of autox and I thought I'd share the results. There is also an article in the months Grassroots Motorports magazine comparing competition tires.

All of my experience prior to this year has been in my Mitsubishi Eclipse GSX, so there will be differences between that and a S2K. But I think the comparison will still be valid.

5 years ago I ran a set of BFG "old" R1 tires. These are not the g-Force R1s, but a prior model. They were an asymmetric carcass design - the inner sidewall was stiffer than the outer sidewall. As a result, during cornering the outside wall compressed more than the inside wall and the tire gained dynamic negative camber and the tread stayed in better contact with the ground. That year, the R1 was the tire to have for autox. Most of the fast national drivers were using them. I ran these for 3 years until the tire was discontinued in favor of the g-Force R1.

As the R1 was discontinued, drivers started changing to the competing tires - the Kuhmo, g-Force, and Hoosier.

Two years ago I switched the Kuhmo Victoracer V700, mainly for cost reasons. They are cheap and last forever. I used them for an entire season, a open track day, and part of the next season. They still had tread left, but had no stick anymore. They worked well on the car - turn in wasn't as crisp as the R1s, but they had good overall grip. They are almost immune to flat-spotting and are a good tire for newer drivers who will spin the car a lot.

Last year, I tried the g-Force R1 tire. I really liked it better than the Kuhmo. It had better responsiveness and turn-in that the Kuhmo but didn't grip as well in sustained manuevers (like long sweepers). Due to complaints about the durability and performance of the tire, BFG tried making a g-Force R1A tire. It was designed for high HP, well-balanced RWD cars with adjustable camber (like the S2K). I never tried them, but a lot of people were having significant durability problems with the R1 & R1As - only getting 20-30 autox runs on a set of tires. BFG has discontinued both these tire as well, but Tire Rack may still have some in stock.

This year we are running the Hoosiers on the S2K. They have great turn in and responsiveness. The Hoosiers are expensive os they aren't for everyone. A set it about $150 more than the Kuhmos. I've also raced a S2K on Kuhmos and didn't like them as much. The car seemed to push into corners and oversteer out of corners. This is probably fixable with shocks, but the car I drove didn't have them.

The national S2K autox'ers are running (in no particular order):

Ron & Annie - Kuhmos
Joe & Anna - Hoosiers
Us - Hoosiers
RandyP - Kuhmos
Mack - Kuhmos
Greg Lee - Kuhmos
Jason Keeney - Hoosiers
Steve Sucsy - Hoosiers
Mike Solomon - Kuhmos
Etgar - Hoosiers
Racerx - Kuhmos

So it's a pretty good mix of Hoosiers and Kuhmos. Joe & Ron usually run competitively so there may not be an ultimate performance difference but more of a driver preference issue. No one at the National level is running Yokohamas or Toyos.

According to GRM article, on the road course they used (Carolina Motorsports Park), the Hoosier was fastest, followed closely by the Kuhmo, and finally the Toyo.

Avg times for each driver:

Toyo Hoosier Kuhmo
Stu 121.81 120.41 120.62
Tom 120.14 118.55 119.13
Dave 126.19 124.89 124.92

The article doesn't appear to be online, so I can't reference it. Go to their site www.grassrootsmotorsports.com and get a free copy or just buy it at a newstand.

I hope this is helpful to people trying to determine which tires to buy for autox and track use.

SoloVR6

I was rather impressed with the times they were getting out of the Toyos. What also struck me is the weight difference of the Hoosiers, impressive.

I'm Hoosier all the way (especially when they're donated) and will resort to the S02's for rains.

CoralDoc

[QUOTE]Originally posted by soloiiracer
[B]The article doesn't appear to be online, so I can't reference it.

solo2racer

Some more information from Alex Tziortzis (a nationally competitive FS Camaro Z28 driver).

Does everyone who autox's in Chicago read this board?

fluxen

Having run both the 2000+ Kumhos and now the A032R's, my guesstimate is that the A032R is about 2-3 seconds slower on a 2 minute course than the Kumhos. What do others think?

I pretty much knew this when I was looking at the A032R, but I needed a tire I could use on the street and track, for which it fits the bill very well so far. It also makes an excellent rain race tire, and others have said it makes something like (don't remember exactly) 8-10 seconds on Kumhos on a 2 minute track.

Stealthy_S2K

I have agree with you, fluxen. I have been using Yoko A032R for 2 years now. It is great for spirited and track driving. I, too, have experienced that also. Although, I don't have any lap time with me. My friends with 944 Turbo S have experience Kumho, R1 and A032R on Waterford, one of the local race tracks here. He really likes the old R1 as stated. But since they don't have it anymore. He opped for the Kumho. and, also tried A032R on the race track. Kumho is about 2 seconds faster compare with A032R with 1:20 lap time. For those who don't know the track layout, here is a copy of it.
1.4miles per lap.

Although, here is one of my Can-Am Racer friend told me. A032R are street tires that behaves like a race tire. but, last heck a lot longer.

fluxen

Yep, aside from the super-swamper humming, I like my A032R's. They're grippier than a street tire, but definitely suffer compared to the semi-slicks like Kumhos and Hoosiers...Good to have my estimate confirmed, thanks.

SoloVR6

[QUOTE]Originally posted by soloiiracer
[B]Some more information from Alex Tziortzis (a nationally competitive FS Camaro Z28 driver).