StageOne

I have been running on Kumhos on asphalt for a while now and seem to have found that 38F / 45R seems to work well. But next weekend I'm heading to the ProSolo in Peru, IN. Does anyone have recommendations for pressures on concrete?? I'm driving a stock Type R.

Absolute pressures would help, but also let me know about how much psi you adjust for when racing on concrete vs asphalt.

Thanks

lundgren

It all depends on your car, but for what it's worth I ran 40 front, 35 rear.

DB2-R81

Just to give you some idea of the variance I run on coarse weathered runway concrete most of the time and my 1993 GSR weighs less than 2400 pounds. 39 front 38 rear, V700, 205 X 50 X 15.

J28S

I've been out of the Auto-x scene for a while now. And, you won't like this reply, but if you're going to Peru (concrete I think) this weekend, you'll see the top running Type R's with 205s on the rear, 225s on front running 38 to 39 front and rear (205s help rotation on concrete). That's my two cents worth. Ron Bauer may or may not be at Peru this weekend, but if you ask, he may help. He and Annie Gill ran a Type R last year. Good luck

typer_801

Sean,

With 225F/205R's at Peru, you can run 41F/41R. This is, of course, assuming your R is completely stock. If you're toe'd to zero in the rear you may want to raise pressures a pound or two to keep the rear in check. Tire pressures are a little course dependent too. With a tighter slower course (very possible at a Pro), you'll have to drop pressures a little more to get enough rotation.

See you this weekend!

DFauth

When I ran Kumhos last year, I ran 40-41(cold-hot) in front, ~37 in rear (changing by +/- 1psi to suit the course). I ran the same pressures on concrete or asphalt and it seemed to work the same on both surfaces for me.

David Fauth

00R101

David,

What pressures are you running the Hoosiers at (both concrete and asphalt) ? I started out with what Hoosier Tom recommended (55F 40R) butI am now at 51F 45R on concrete. Haven't run on asphalt yet and am interested in your opinions.

Regards,
Alan Pozner
2000 ITR
Shockteks
3mm shaved stock front sway bar
1/4 toe out front

Todd00

You guys are running Hoosiers on 6" wide wheels in GS? I assume you are using the 205/50's all around? I had heard that Hoosiers didn't work well with a 6" wide rim.

Whenever I get some cash I was going to the 225/205 Hoosier combo, but then again I'm running in a different class with 7" wide wheels.

lundgren

I asked David at our last event, and I'm sure he will correct us, but he said something like 51 front (225/45s), and 46 back (205/50s)

I have just got my 225/45 and 205/50 hoosiers, and while I have a 7 inch rim, I'll most likely start around 50 front, and 45 back, depending on how the car rotates.

DFauth

Tell you what I run for pressures now? And give away my secrets? Never!

WIth the Hoosiers, I run the same pressures whether on concrete or asphalt: 50-52(cold-hot) front, 46-48 rear (course dependent, generally 47).

As far as running 225 Hoosiers on 6" rims: the Miata guys have been running them for a while now. I did back-2-back testing between the H-tires and the K-tires and found that the Hoosiers were just a *bit* faster. I went with them because I didn't feel that I was spending enough money on tires, so I need to get some that were more expensive and didn't last as long!

David Fauth

DFauth

Alan,

Somewhat off topic: what do you mean in you signature by "3mm shaved stock front sway bar"? I've always run the stock bar.

David

00R101

David,

Thanks for the pressure info - I ended up with the same - Nice to know I'm in the ballpark. Now if I can only run your times

I took a grinder to the bottom of the stock front sway bar and took off about 3mm from the bottom for about 12" on either side right where the bar does a 90 degree turn. I felt that a softer front bar would help with rotation. I had driven Jeff McRae's '98 ITR (which he got used from another auto-xer from Chicago) and I liked it. He had a custom bar (21 mm instead of 24mm) I could not find anyone willing to make a bar for anything approaching a reasonable cost. So I ground the stock one down. I figured that if it did not work out I could always buy a new stock one for less than a custom.

The result is a very small improvement in front grip resulting in a slight increase in rotation. Really not very noticeable.

BTW as far as Kumhos vs Hoosiers - I have 225 /205 combination Hoosiers and Dale Kunze had 225 Kumhos all around. He and I switched cars at the practice event the Friday before NEDIVs and on the Rome concrete both of us were 0.6 faster on the Hoosiers on a 35 second very tight course.

Regards,
Alan



[Modified by 00R101, 11:55 AM 8/16/2001]