Hoosier R6/Kumho V710 tire pressures?
06-10-2009, 04:15 PM
#1
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Hoosier R6/Kumho V710 tire pressures?
Ok... so I've got R6s on the Panoz now and 2 sets of V710 scrubbs for after I run through the R6s.
I haven't run a Hoosier since I had some RS304s on my Corvette a few years ago. From what I remember those liked to be in the 42-44psi range hot. Are the R6s the same? What type of hot pressure to you shoot for? What type of cold pressure do you typically start out with?
Same for a V710? I can't remmber what pressures these liked... I think I remember them being on the other end of the spectrum from the Hoosiers... something like 33-35 psi hot and mid 20's cold?
Since the Panoz is pretty much a new car what with all the off-season mods I'm going to start out w/ equal pressures f/r but -1lb on the left hand side for VIR as it's mostly right turns.
I haven't run a Hoosier since I had some RS304s on my Corvette a few years ago. From what I remember those liked to be in the 42-44psi range hot. Are the R6s the same? What type of hot pressure to you shoot for? What type of cold pressure do you typically start out with?
Same for a V710? I can't remmber what pressures these liked... I think I remember them being on the other end of the spectrum from the Hoosiers... something like 33-35 psi hot and mid 20's cold?
Since the Panoz is pretty much a new car what with all the off-season mods I'm going to start out w/ equal pressures f/r but -1lb on the left hand side for VIR as it's mostly right turns.
06-10-2009, 04:52 PM
#2
Le Mans Master
I usually start at 30 cold on all 4 and adjust from there as needed. I'm on a street alignment and those pressure still feel pretty solid.
Here's some good reading on the subject from Hoosier's site:
Here's some good reading on the subject from Hoosier's site:
https://www.hoosiertire.com/rrtire.htm
Tire Pressure Recommendations For Competition
Traditionally, Hoosier tires have often required higher pressures than other brands. This has changed with the A6/R6.
Roadrace/track applications
Vehicle size
Recommended Hot Pressure
Cold Pressure
1800-2200 lbs.
34-37+
26-31
2200-2600 lbs.
35-38+
27-32
2600-3000 lbs.
37-41+
27-32
over 3000 lbs.
38-43+
27-33
+Higher pressures will improve the performance capability but will require a more sensitive feel to take advantage of the increase.
One characteristic of the tires is the tendency to "skate" initially (when inflation pressures are correct). It is important to resist lowering the pressure to attempt to eliminate this feeling. Dropping the pressure too far may improve the "feel" of the tire however it will also lower the performance and increase the wear rate.
Tire Pressure Recommendations For Competition
Traditionally, Hoosier tires have often required higher pressures than other brands. This has changed with the A6/R6.
Roadrace/track applications
Vehicle size
Recommended Hot Pressure
Cold Pressure
1800-2200 lbs.
34-37+
26-31
2200-2600 lbs.
35-38+
27-32
2600-3000 lbs.
37-41+
27-32
over 3000 lbs.
38-43+
27-33
+Higher pressures will improve the performance capability but will require a more sensitive feel to take advantage of the increase.
One characteristic of the tires is the tendency to "skate" initially (when inflation pressures are correct). It is important to resist lowering the pressure to attempt to eliminate this feeling. Dropping the pressure too far may improve the "feel" of the tire however it will also lower the performance and increase the wear rate.
06-10-2009, 07:15 PM
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I have been struggling with the R6 pressures all this season. So far I have been frustrated with them. Every event I do I find out I ran quicker last year with worn out Kumhos. The last event I did at Watkins an acquaintence had the same size R6s on his C6Z and he corded the outside edge of one tire. He is running a stock alignment and starts his tires at 32 psi cold.
When I tried the pressures he started with I had severe oversteer. Lowering the rears a couple of pounds helped and adding a pound to the fronts helped some more but the car is still twitchy and likes to step out the rear under power. The car is just not as stable as it was last year. Front and rear tie rods are in good shape and all the wheel bearings are in good shape. Now I am wondering if I need more rear toe in to get the back under control.
Bill
Bill
When I tried the pressures he started with I had severe oversteer. Lowering the rears a couple of pounds helped and adding a pound to the fronts helped some more but the car is still twitchy and likes to step out the rear under power. The car is just not as stable as it was last year. Front and rear tie rods are in good shape and all the wheel bearings are in good shape. Now I am wondering if I need more rear toe in to get the back under control.
Bill
Bill
06-10-2009, 09:11 PM
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Kumho 710's like much lower pressures than you're used to on other DOT radials. On a 2300-2400lb. car, we shoot for a hot pressure in the 34-35 lb. range, and start off @ 24-26 lbs. cold. They're a whole lot different from Ecstas, or the old Victoracers.
You'll probably go a little higher due to weight, but stay the hell out of the 40's hot...bad ju-ju there.
DK
(who co-drives endurance races with the Kumho Motorsports tech center guys, so I'm not just making this crap up like the rest of the iNTaRwEBz experts do)
You'll probably go a little higher due to weight, but stay the hell out of the 40's hot...bad ju-ju there.
DK
(who co-drives endurance races with the Kumho Motorsports tech center guys, so I'm not just making this crap up like the rest of the iNTaRwEBz experts do)
Last edited by Don Keefhardt; 06-10-2009 at 09:14 PM.
06-10-2009, 09:14 PM
#9
Melting Slicks
On Rs/A's I'll run like 22/20 F/R cold.
Since your car is significantly lighter, I'd bump those up a couple pounds each. I talked to the hoosier folks at nationals, they said shoot for 35 hot. I know its not what their manual says... but its what works.
Since your car is significantly lighter, I'd bump those up a couple pounds each. I talked to the hoosier folks at nationals, they said shoot for 35 hot. I know its not what their manual says... but its what works.
