What's a good tire pressure to run on our stock advans for auto-x? I talked to one guy who was over 2 seconds faster than me. He told me he was running 50 psi on his advans in front and 45 in the rear! The max rating on the tire says 40 psi.

 

thanks for ALL of your info EVERYBODY!!!!!!!!!
I'm still reading it, but i want to thank you all before i'm done.
i'm not running on stock tires, I WISH!! $200 a piece to replace...anyways, i am comparing wrs, one was 8 seconds faster... some STi is only 1 second faster...of course there's cars that took more time, but i just want to focus on the cars that got less time...
one more thing is...ppl suggest i do a late hard brake and "slide" (not drift) into an apex...sometimes i don't really know how to apply the brake...should i do what he suggested or there's a better way?
thanks again for all the info guys

 

I'll focus on time and not cars then.
there's auto x in my area once a month. and i commute to work alot and i don't wanna waste those "auto x tires" for commuting, what should i get?
does tire pressure make THAT MUCH DIFFERENT??

 

yes, tire pressure makes a lot of difference. If you know someone who has the same tire, and they're making better times than you and they tell you what tire pressures they're running- switch to those pressures. The sidewall "max" is really just a recommendation Pressure is something you should be watching all the time, too. If you're in a good spot with your tires and add 2 degrees from a run, then the next run won't be as good. you need to keep the pressure where you like it between runs.

Are you using chalk or white shoe polish to see if you're rolling over the sidewall of your tires (too little pressure)? Are you checking your tire temps between runs too see if the middle is hotter than the edges (too much presure)? Is the outside hotter than the inside (need more neg camber)?

It's possible to get too much pressure, though. I'm finding that I need to run about 5# less than what I have been. Even a little less might help, but we'll see next event

 

I run my stock Advans right at 40psi (heated), which means I set them at 38psi before I start. I try not to go more than 1psi over 40, since that's what the tire says is max. I'm surprised that guy runs his tires at 50psi without the tires getting damaged.

 

I thought max tire pressure has more to do with your comfort as a driver on regular roads and fuel economy, than it does with how much pressure the tire can withstand before being damaged.

the instructor at DE said he never ran less than 55 in the front and 57 in the rear on his hoosiers. I'm finding 45 f 43 r is workign out good for me on my Azenis on a hot day.

 

The "max pressure" rating on a tire indicates the maximum pressure at which the manufacturer will warrant the tire's performance. It does not in any way represent a pressure above which the tire will be damaged.

Probably any modern radial can handle pressures of 50+ psi for autocross without any significant risk of damage.

 

hmmm.. I'll probably stick to a max of 40 psi tire pressures on my advans. Given how expensive these tires are, I'd rather play it on the safe side. hehe.. I haven't even played w/ my shock settings yet since I'm still working on my driving skills.

 

I'm running around 41f 39r on the Advans with a stock 05 'RS on a fairly grippy asphalt surface (Qualcomm). Running about 1.5s off of the fast AS/slow SS guys while waiting for suspension bits to show up.

KeS

 

get some chalk or white shoepolish (likely can be borrowed at any auto-x event) and mark from the mid-sidewall and into the thread. This mark will show you how far your tires are rolling over in order to keep rubber on the ground during hard turns. If it rolls over far add air; if not at all subtract air. A good tire gauge is pretty essential (and relatively cheap).

Pressures can be dictated by driving styles - as your style changes (becomes more smooth or more aggressive) it's worth marking and watching. A pyrometer measures temperature of the rubber of the tire itself and can be used to gauge temp across the entirety of the tread. This is a more expensive device but can bring a more exact pressure requirement - STICK WITH SHOEPOLISH AT FIRST! *Laugh*

Otherwise, one of the first things I was told was that when I'm hitting a corner and feel the need to hit the brakes - wait for a count of one and THEN hit them. I was always braking way before I needed to - a good street habit but not on an auto-x or road course!

Again, talk with others, find someone in your class who's friendly and experienced. If your class is full of non-communicating morons talk to organizers and such for someone they'd recommend you to talk to about learning more about your car's setup and driving!

Most are more than willing to help - especially the experienced folks - and they're generally very nice about it AS LONG AS YOU'RE WILLING TO LISTEN and show some gratitude...

By all means get to as many events as you can!

 

There is another thread floating around here on tire pressures..

but OEM Advans, Autocross.. (and even some tight roadcourses) I like 38 front, 45 rear cold. I keep bleeding the fronts to make sure they stay around 38/39 hot on an autocross course, and let the rears drift up to 46-47

I have half a dozen autocrosses on stock Advans, and now with my experience in the car I might even go higher in the back. (but its been a while since i ran on Advans for autocross)

This helps the car rotate on corner entry, then you can use the throttle to drive the car off the corner (making it faster down the straights) What you are doing is creating enough corner entry rotation so that the normal on throttle evo push doesn't cause you to have to get back out of the throttle.

On a road course, the tires usually heat up to 50-51 hot front and rear.

Hoosiers, the S04s typically run some really high pressures. In my 1778 lb CRX i was running them 51f/56r cold, so i could see mid 50s on the evo for sure.

Jon K
www.seat-time.com

 

I guess tire pressure settings will vary from car to car, and setup to setup. I have a quaife front LSD, so that helps me kick the rear end out slightly around corners w/ my current tire pressures (37psi cold all around). So I should probably stiffen up the front shocks to help balance the car out more.

 

Thanks for the advice, because I probably need to use it. In my auto-x this weekend, the course was very short and very tight, so I was having a difficult time overcoming understeer while maintaining speed on the stock tires. I think I performed admirably by finishing 7th or so out of 60, but I was 1.4s off the FTD (hoosier slicked 92 hatch w/K20 motor). 2 weeks ago, I was only .9s off that same car's time in a longer course with less tight turns and more straightaways. Considering the one 2 weeks ago was my first auto-x, I probably drove BETTER in this last one, but the dynamics of the track kept me from doing as well. The good thing, though, is that everyone who beat me was on race tires. At the next one in 2 weeks, I'll have Kumho Ecsta V700s, but it will be my first time ever pushing a car on R compounds, so I'll have to feel 'em out at even pressures before deciding whether to increase the rearss significantly.

It will be very interesting to see how much of a difference the tires make...

 

best advice though.. pick something one of us has said.. all of the pressures are close... driving style will be what makes the most difference, and the course.. car to car (as long as mods are the same) it wont change much.

Once you get the pressures set, since its early in your autocross experience.. dont touch it. (other than to bleed so its consistant)

If the car is pushing, slow down or pick a later turn in.. teach yourself how to deal with it first and then you can learn to make better adjustments that fit you later.

Jon K
www.seat-time.com

 

which part of CA?
I attend socal scca solo2 (CSCC) events monthly...