Hey all,

I just put on some new 245/45/16 Hoosier AS03 tires on stock wheels. I'm running between -2 and -2.2 degrees camber that worked awesome for my car running Kuhmo Victoracers running 31-33 psi cold.

Hoosier recommended that I run between 40-42 psi. Well after 10 runs this weekend the very outer edge of the Hoosiers still have the little nipples on them. The front tires are just scuffing the nipples off, the rear tires still have the nipples on the edges of the tread.

What type of pressures do you guys run with these tires? The car felt pretty sticky, I PAXED out 1st on Sat and 4th on Sun out of about 110 cars so I'm happy with the grip, just not the potential tire wear issues.

Oh the car is a 93 R1, Eibach springs, GAB R shocks and a 32mm hollow front sway bar. Weight is right around 2760lbs varying slightly depending on how much gas I have in it.

 

on my RS303. it start to hadel funny when pressure over 40 psi hot. so I alway keet 35 psi cold

 

Take this with a big grain of salt but I know the "top guys" Nationally in SS were running pressures in the low 40's on S03's. I have yet to run on an out of the box set of Hoosiers on my own car but plan to be on them next season. This season is winding down in another month or so and I have enough Victoracers left to make it through.

 

Invest in a tire temp guage, pin style, not laser type. Do a run, have 2 friends that can read and write, take the temps as soon as you come back in to the pits. Start from the inside, middle, then outside of tread on each tire. Write all tire temps as you read them in the same order.


LF 180 200 170........................ RF 180 204 185
LR etc ........................... RR etc Do it the same way everytime!!

The higher the number, the hotter the rubber. If the middle is hotter, let air out. If colder than the outsides, add air. If the inside is hotter than the rest, take out negative camber, and so on.

Big boys just don't add air to manufactures specs. They check tire temps to determine what the car is doing on the track, and adjust so forth. Keep a log of each event specifics as in temp, weather, track condition, etc. You can use it for going back to the track at a later day. Alway write down any adjustments and or repairs to suspension.

You may find that you will have varied tire pressures all the way around your car. No big deal. Let the tires tell you what you need. Start at 35 and work from there.

Russ

 

Do you guys bleed the tires as the temps go up?

This weekend I'm going to this event called the "Enduro", basically 5 laps around a go-kart track, one run only, you blow it you go home...

I hold the SM2 record @ 4 min 05:xxx sec. This year I'm going out with fresh Hoosiers and shorter gears that should really work well on this track, I'm hoping to be the first door slammer car under 4 min there. This event has been going on for over 20 yrs, only "mod" cars have gone under 4 min and not by very much.

Since it is a long event for a auto-x I usually start the tires with a little less than idea pressure so I end up with a little more than ideal pressure at the end.

 

Your right I should get one of those. Do you know a good source?

Thanks for the tips!

 

A little google.com work and I bought a Pyrometer from Longacreracing.com.

Let's hope for under 4 min!

 

Yep. Once I get the pressures up after the first run I constantly bleed them down to maintain what I want.

Good pyros are available from any number of places. I bought mine from www.racerpartswholesale.com Figure about $100 for a good probe type no matter where you go.

 

If you really want to be cool, you can get tire pressure bleeders. You set them by shims and springs to keep the pressure at the level you want. Mostly used by circle track and road racers. Requires additional stem hole in wheels.

Go to a local book store and look in the Auto section, there is a author named Steve Smith, does a complete line of stock car books. Has a simple and very imformative book on setting up suspension and tires. About $24, good investment.

 

44 lbs ? that's too high. that's the max the tire is recommended to run, hoosiers have stiff side walls and do not need too much air pressure , Kumhos run good on 32 pounds, We run a Road course GT3 RX7 in TCRA with Hoosiers also but we run the newer compound R3S04, 285-30-18 all around, We run 22 pounds cold on the front and 23 pounds cold on the rear , We run 20 lap races so the tire gets really hot, if You auto cross , Given the fact the tire doesn't have much time to heat up, I recommend you do not exceed 29 pounds front and 30 pounds rear.

 

Interesting discussion. I run 225/45-13 Hoosier R3S03's on my ITA RX7 (1st gen) and it is best at hot pressures in the 42 - 43 range. Depending on the ambient and track temp, I start them at 35 cold.

Running the same tires / rims on my CSP RX7, I run 43 / 41 front / rear with excellent results.

Of course, first and third gen cars are quite a bit different, but Hoosier also told me their tires work best in the low 40's hot.

 

I have found that as close to 40 psi is the best place for traction and life of the tires. I use the laser type temp sensor, i have seen no problem doing it this way. On a normal 80 degree day I'll start all my tires at about 36 and run a few good laps and then once tires are up to temps. I add or release air as i need.

 

For the A3S03's, I ran 42psi (F) and 38psi (R) for 245/45 16's. The A3S03's need a little heat before they get REALLY grippy ... but they get sloppy if overheated. Typically, I would start at these pressures and bleed off during auto-x events. For this enduro event, I would drop the pressures 5-7psi. Keep in mind, that's just a rough guess. Good luck!

-Don

 

I've read about some overheating issue with other cars, I'm hoping I won't have that problem, I didn't have it with the Kumhos.

So with my camber and weight will I have overheating issues, 4 min, really tight, speeds in the 35-75mph range?

Here is a pic of the track, the course to follow is the outside of the entire track. Max speed for me will be right around 75mph on the straight. The only place I hit 3rd is on the straight.

http://www.ssccmedford.com/Track.htm

Just in case your curious, here are the records.

http://www.ssccmedford.com/X_2003/Re...uroRecords.htm

My mods after last year, vented hood, new Hoosiers vs. 3 mo old Kumhos, 4.33 gears.

Driving is key of course but I'm hoping the gears, hood and Hoosiers can buy me 1.2 sec/lap!

I know this course like the back of my hand, I've been racing there for 7 yrs, I'm nearly 1 min faster than I was 7 yrs ago.

Thanks for the tips guys, I bought a pyrometer and I'll start testing (2 practice days) with about 40psi in front and 38psi in the rear, then I'll bleed a little from there for the actual event.

 

Jeff you know my tire size and I run 40/38. On cold days I will start lower 36/34 or lower if it is really cold.

Allan

Good luck and watch out for Tom.

 

Roadrace guys keep in mind that turbojeff is asking about AS03 tires which are different beasts from RS03 tires.

 

Hey guys thanks for the input.

I tested tire temps on Friday afternoon and Sat practice. They were inconsistant at best and I'll post them later.

Basically this event is a comprimise. It isn't a road race and it isn't a auto-x. My tires were at 175F at the hottest after 2.75 laps in practice, the actual event is 5 laps.

I ran a 4:08.xxx compared to a 4:05.9xx last year. I was disappointed at best but still no car has run under 4 min, a 240Z ran 4:00.6xx this year but was driving easy to avoid overheating the tires. Anyone remember Rod Millen trying to get under 10 min at Pikes Peak, IIRC his best is something like a 10:00.xxx.

I was 4th or 5th overall, no car with AC, PS, cruise, etc was faster, although a guy in a stock STi ran 4:16.xxx which is absolutely smokin'.

 

I also forgot to mention that Hoosiers can actually be slower depending on the surface. If the surface is very gravel-ly, then the Hoosiers end up picking up too much junk and get awfully loose. I learned that lesson at Miserable .. er, Mineral Wells. The car just would not do what I wanted it to. And Hoosiers do take some getting used to. The transition response is a lot faster than the Kumho (at least Victoracers and Ecsta V700's) and they are very unforgiving. Push the limit too far and they will just let go. But, the ultimate grip is still better.

BTW, the STi is a very easy car to drive fast .... I drove a couple while instructing at a novice school. AWD and power lets you do some stupid stuff.

 

Yeah I think I liked the Hoosiers on the short course auto-x better, but I think the Kumhos work better for this short track.

I've noticed that the Hoosiers don't forgive a little over the limit action like the Kumhos did. Hopefully next year I'll go back with slightly more power (12psi vs. 10psi) some fresh Kumhos (maybe the 710s?) and see what I can do.

The surface was relatively clean since people had been running practice for 2 days and I ran towards the end of the day.

There was a typo in my last post, the STi actually ran a 4:14.xxx. Only 9 sec off my best time and 6 sec off this years time.

 

You will like the V710's. Everyone does. It's the fastest auto-x compound out there. I'm talking 3-5 tenths faster than the Hoosier on a typical 50-60 second course. I've almost chased down some well-driven Prepared times locally on the 710's.

 

Wow, old thread. I'm back into auto-xing and running the same setup as listed above with the exception of running the Hoosier A6, 245/45/16.

I've been running 31-32psi all around, just a touch of understeer, I feel like I can put the power down in most places but in fast corners the front will push just a bit w/o throttle.

Any recommendations on pressures for the A6?

 

I'm running 29 front 27 rear on 245/45/17s and 275/40/17s on my FC...

it depends on a lot of things though, like your wheels size and suspension setup... you should buy a pyrometer and measure your tire temps on the outside, middle, and inside. and also chalk your tires.

 

Road race FC we run 29 front 22-23 rear with both A6s and R6s...

 

road racing, R6, 225/45/15's. target is right around 35psi HOT, although the tires do not seem to be that picky.

this starts us at like 26-29 depending on which tire and which track, infineon for instance is all right turns, so the left tires start @27, the right start around 29...

 

Yeah i should add this is cold pressure, for autoX i imagine you would start them higher.

We also run the rears lower because we have the rear sway bar attached.