Hoosier A6 tire pressure?, their doc advice seems high to me Options

[mskala]

Upgrading to Hoosier A6 205/45/16.

Looking at the documentation they have, seems like pressure recommendation
for even light cars is 30-33 psi. I've been running kumho V710's at 24psi so
this seems odd to me. Of course googling this yields lots of opinions for much
heavier cars than ours. Just wondering if anybody has any experience here.
I'm running 7.5" rims.

Do these things have really wimpy sidewalls or something?
Thanks

[Jetsetsurfshop]

22 fronts, 26 rears, worked for me. This is the cold pressures.
I have 205/50/15 on 7 inch rims.
Good luck. My favorite part on my car is my A6s. (IMG:style_emoticons/default/driving.gif)

[mskala]

22 fronts, 26 rears, worked for me. This is the cold pressures.
I have 205/50/15 on 7 inch rims.
Good luck. My favorite part on my car is my A6s. (IMG:style_emoticons/default/driving.gif)

Do you let them increase pressure as they get hot? I was always setting one
value and letting out air as they heated.

Thanks,
Mark S

[brant]

21 cold all around....

I had help testing by a hoosier tire tester/coach
we lowered in two pound increments starting at 27
ended up at 21 cold.

1835lbs.

[Jetsetsurfshop]

22 fronts, 26 rears, worked for me. This is the cold pressures.
I have 205/50/15 on 7 inch rims.
Good luck. My favorite part on my car is my A6s. (IMG:style_emoticons/default/driving.gif)

Do you let them increase pressure as they get hot? I was always setting one
value and letting out air as they heated.

Thanks,
Mark S

I always checked them before each run. Letting a little out each time.
My car 1961lbs.

[Jetsetsurfshop]

21 cold all around....

I had help testing by a hoosier tire tester/coach
we lowered in two pound increments starting at 27
ended up at 21 cold.

1835lbs.

Is that your track pressures too?

[brant]

Yep. The only autox I ever ran was 1 time in 89 or 90.

I'd like to do it again

[Joe Ricard]

AX is quite a bit different than road racing. cone dodging runs are 40 to 60 seconds on average and this is not enough time to get an A6 / A7 up to temp. If you cover the tire between runs and have a co driver you will be closer on 2nd runs. you should be shooting for 120 ish degrees. 140+ and they will get slippery. You can adjust temps with pressure higher pressure will get the tire to heat quicker. (grips more on a smaller contact patch).

It's not that the side wall is soft but rather you are generating some pretty significant lateral loads and the tire will just plain stick until it snap lets loose. Higher pressures run by most hot shoes is to keep the carcass from deforming and let go gradually. At some point the tire face is round like a balloon and this will reduce grip on that end, also a tuning tool.
In the end only the timer will tell you what is faster for your car. Like Brant did in his RR car. Doing this all the time in my kart. and sometimes it felt faster and more comfortable but was slower . so butt dyno is not a good tool.

[Woody]

I was running 22 front and 21 rear hot pressures with a 225/275 combo on 15s. My car weights 1850 pounds.

[mskala]

Thanks all, this is good info. We usually get 4 runs then wait several hours for
the next 3 or 4. With V710 I usually got the things hot by 4th run, sometimes
close for 3rd run. No co-driver. So hopefully this compound starts working
for me quicker.

Even at 24 psi, I would not hit the little arrows on the side of the tire for V710's.
Based on what Joe was talking about, I guess the goal isn't always to get to
there. The A6's look pretty rounded vs. squared at edge of tread, so I hope
that lets them give some warning before letting go completely in a corner,
without going to ridiculously high pressure. Also they're not squeezed onto a
5.5" rim. Due to the step outward molded in next to the bead, the sidewall
actually goes inward toward the tread.

[Joe Ricard]

I was running the 205 Hoosiers on 8" rims for a fairly vertical sidewall.

[Randal]

I was running 22 front and 21 rear hot pressures with a 225/275 combo on 15s. My car weights 1850 pounds.

+1

[mskala]

Car is 2000lb + me, and I've got the narrowest 16" hoosier (IMG:style_emoticons/default/biggrin.gif) . In fitting
the things, I've measured that they are 1/4" wider section than the 215/40
V710s. I've tried to make more room, and applied a tiny bit more spacer.
Still, things are tight as hell and I can't determine rub until first event in a
couple weeks, so I'm going to hold them at 25psi first day.

[r_towle]

22 when I had hooziers

[r_towle]

22 when I had hooziers

Put some shoe polish on the sidewalls