Yellow Z

Autocross. C5. T1 suspension. What are the correct operating pressures (hot).

John Shiels

If you like search "hoosier tire pressures" plenty to read and not much agreement.

TedDBere

start with:

32 front
28 rear

...and adjust from there.

drivinhard

Just my .02 (worth about .01) but we run our TT's about like an autox (ie, need all the grip in the first 1/2 laps) and the lower I've run them, the faster they go.

20-23 rear
21-24 front

or lower

brkntrxn

Mark,

So you are running A6s? I thought surely I misunderstood you at CMS and assumed you were running R6s.

Do tell, inquiring minds want to know.


-Kevin

drivinhard

275 A6's @ CMS

might play with 295 R6s in the heat of summer though

96solo

You go lower and you're running the risk of premature inside wear and the tire losing bead on the wheel, especially in the size 305x17!

The operating temperature is a narrower range that the Kumho.

Hoosier A6 120-140 degrees
Hoosier R6 125-145 degrees
Kumho 710 110-170 degrees

D.J. Covert
2008 NASA-AZ TTS Champion

Sgt.Gator

Straight from Hoosier, TIRE CARE TIPS FOR R6 & A6 TIRES:

http://www.hoosiertire.com/Tctips.htm

thehammer69

I'm running 315/18 A6's on both front and rear Autocrossing.

Fronts: 34-36 psi
Rears: 29-30 psi

Any lower and they roll over too much and have less grip.

AU N EGL

Individual experience will very. Most ppl will say those pressures from Hoosier are 10 psi too high especially when HOT.

John Shiels

been down that road. personally I think many are faster lower because it is easier to drive at lower pressures and not as sensitive to steering input. I like 40 hot and I start at 32 frt and 30 rear on a 50-70* day. Low pressure and they roll like a rock'in chair, turn in sucks and cord up real fast!

Yellow Z

Cording is a real concern for me. I bought a set of Hoosiers a very long time ago and they corded very quickly. I have used V710s ever since. I thought that I would give Hoosiers a try again this year and see how it goes.

drivinhard

I am running A6's this weekend at CMP that I have been using since last august. (they'll be slow, but they probably got 1 more weekend)

I run a lot of camber, no cording issues. They eventually will cord at the edges, but tire life is not a concern really. Going fast is. They'll heat cycle out way before the flat part of the tread is worn out anyway.

I still stand by (in my experience) the tires are faster at lower pressures.

AU N EGL

Ask Wally what pressures he uses. 30HC out of a set before cording is great.

and we all know who fast Wally is . . . .. . . .. . . . ..


I run my R6s low.

sleeper02Z06

You'll never get a striaght answer on this, everyone will say they are correct. There is definately a window you want to be in, and the hoosier sight kind of leads you to the very high end of that window. Where you are in that window depends on your comfort level and driving style, as well as car setup etc. Pressures can be tailored for certain driving styles and such, no one setting is correct. For this reason I won't get into what I run. What I will state is all those that say A6's cord easily or have shoulder wear or whatever when ran at lower pressures than they believe are correct, are wrong. Want to argue with me thats fine, but I've been there, done it, put tons of heat cycles on them and for perspective just went 2.04 flat in legal T1 C5 with a soft engine at VIR, so if you want to question if I know what I am doing think again. I've not corded a set running lower than hoosier recommended pressures unless they things had like 15+ cycles on them to include race length cycles. Rears never cord, flat across wear, no lines to see in them and still run them.

Joe

sleeper02Z06

Define very long time. A6/R6 are a different animal than the older models. Cording is more dependant on chassis setup and overdriving them then air pressures. If you have poor/wrong alignment or just beat them up it doesn't matter what pressures you run, you can tear them up.

Joe

fej

Most of the autocross guys I run with (nationals level guys, ex champs etc) are within a pound or two of thehammer's numbers.

V710's like less pressure, usually ran them 28/24 or 27/23. This year I will run the 295/30/18 A6 square and start around 32/28 and see how it goes.

Fej

AverageVetteNut

I've used varying PSI's at different sites...

I started with higher #s ( 34-36 F, 30-32R ) and while they were quick, they didn't really get better and a bit more predictable ( for me ) until I went @ 30-32 F, 26-28R and the car really felt better there.

Like many have said... everyone's driving style, the surface you're running on, the ambient temps of the site and even the amount of rubber down will affect the grip and wear.

I'd take a bunch of different #s from here, and see where there's a decent average, and then maybe start there and play around a bit.

Maybe you're local region has a test n tune coming up you can mess with psi there?

ryan0

laugh if you want...

we started WELL under any number posted here this past weekend.

we rarely cord... usually heat cycle them out before that happens.

drbenne

I agree with Ryan. The A6s seem to perform much better in the 28 psi (hot) range that higher pressures. no noticeable increase in tire wear with our alignment settings as they are.