Author Topic: Get those pressures up front... (Read 4305 times)

Alpine003 · « **on:** November 01, 2006, 11:25:50 AM »

Recently got new tires and they inflated them to the usual and safe 32 front and 35 rear(boring). I had a heck of a time driving with this setup. Changed it a few times and finally settled on 37f, 35r for the streets and made a world of a difference with my H&R/Bilstein Sport combo.

Taking 100mph sweeps in the exit lanes seem a lot more confidence inspiring without having to do any steering wheel corrections.

How many people here like having higher front tire pressures?

asubimmer · « **Reply #1 on:** November 01, 2006, 12:22:21 PM »

I'm currently about 36 all around on the street. I haven't messed w/ other pressures though. I'm running azenis

GuySchalnat · « **Reply #2 on:** November 01, 2006, 04:15:06 PM »

When I was autocrossing on street tires, I found that 37 lbs was the fastest. Now, I wasn't that great of a driver at that point, and I strongly suspect I should have dropped the rear pressures a bit.

I would not be suprised if different street tires want different pressures. It certainly worked out that way with r compounds. Every tire I've tested wanted more front pressure then rear. Of course, for autocross, I WANT the rear to step out at 45mph, so perhaps a bit loose for 100 mph exit ramps. Still, your pressures aren't that wierd.

-Guy

e9nine · « **Reply #3 on:** November 01, 2006, 06:33:24 PM »

For my tire pressures on 15" Azenis. 39/40 on all 4 corners seems to work best. Naturally I am always testing out things in search of optimal pressure so the research still continues as aiming for steady variables is a chase in vain for me....

sheepdog · « **Reply #4 on:** November 01, 2006, 06:48:04 PM »

When I got new tires (Yokes) the installer had 35psi in all 4, and the car pushed a bit.

I dropped them all to 33 and the car balanced out and rode better (stock suspension). Rode softer than my Goodyears at 32 and even gripped a lot better to boot.

Amazing what a few psi can do to tires.

Alpine003 · « **Reply #5 on:** November 02, 2006, 10:28:14 AM »

Quote from: sheepdog;13145

Amazing what a few psi can do to tires.

Amen.

e9nine · « **Reply #6 on:** November 02, 2006, 06:15:37 PM »

A lot of things taken for granted go far down the road. It took me a while to understand the concept of having a test and tune auto-x session. The more you get connected to your car and it's balance, the better you appreciate tuning variables.

IMO the hardest part for most of us is tuning the car before the driver...I've been there and learned a lot from some key people. Naturally if you don't know if your car is loose you won't know where to go next to compensate. If you're taking some terrible lines thus making the car understeer, you will be blaming it on the fact that "e30s are said to understeer" and play with the wrong variable while leaving the nut behind the wheel.

When you think a car is set up wrong - have someone else drive it or critique your style before playing around.

Then again - driving style and YOUR particular setup also plays another critical role.

Alpine003 · « **Reply #7 on:** November 02, 2006, 08:23:03 PM »

Quote from: e9nine;13213

When you think a car is set up wrong - have someone that is more experienced than you drive it or critique your style before playing around.

This is true as I had an instructor drive my almost stock E36 M3 around an auto-x and knocked off more than 2 seconds on a ~55 sec. course. Before he drove it, I naturally blamed it on being stock and not having radical camber corrections like the other M3's. He made the other M3 drivers that had a lot of mods really feel dumb after he drove my almost stock car.

GuySchalnat · « **Reply #8 on:** November 02, 2006, 09:15:44 PM »

That said, there are more and less forgiving pressures. I usually try to steer beginners to a reasonably forgiving tire pressure, and then let them learn to drive the car. Also, if you can get them to pay attention to what the car is doing enough to adjust tire pressures, they'll learn something about driving despite themselves. You have to pay attention to the car, especially if you are going to be driving in unfavorable conditions (different lots, different weather, etc.).

-Guy

mikesjo · « **Reply #9 on:** November 03, 2006, 01:10:03 AM »

Mine are at 32 for the street. Autox it's around 40 cause I don't like to roll over on the sidewall. I'm not good enough to tell how the different psi's affect me on the autox though

.

GuySchalnat · « **Reply #10 on:** November 03, 2006, 07:35:19 PM »

40 all around is a great start. It is better to be too high then too low, you don't lose as much time on the high side, the tires wear easier, and the car is more predictable.

When you feel you are ready, find a test and tune day with at most 50 cars, spend the first half of the day working on learning the course and becoming consistent, and after you can run a consistent lap, start paying attention to the car, not the driver, and then start dropping the tire pressures. Go at least 2 psi, if not 3 psi, until you get in the range. You'll have driven the course enough by then that you'll feel the difference. I like to drop both front and back evenly until I find the maximum grip, then mess with the rear tires until the car just starts to rotate without spinning. Then you may have to adjust the fronts again. Depending upon surface (and temperature for rcomps), I find the rears like 1 to 2 psi less, and once I get the rears right, I sometimes can drop both an extra psi that wouldn't work so well with equal pressures front and back.

As you get better, you get to adjust the tires again. And again. And again. Part of that is smoothing out of your driving style. The smoother you are, and the more you can anticipate the upcoming corner, the lower pressure you can run and get even more grip. It is just that lower pressures are less forgiving, so you have to be at the point that you make less mistakes (or at least smaller ones). We're not talking about much here, and shocks become very important at that time, but that's a good start.

Good luck, and may you be close to all your apexes.

-Guy

sheepdog · « **Reply #11 on:** November 04, 2006, 12:40:45 PM »

The correct PSI is also not the same for each tire (type, manufacturer, size, etc...) or driving condition.

Guys with 18's are probably not going to use the same pressure as someone with 14's.

Author Topic: Get those pressures up front... (Read 4305 times)

GuySchalnat

GuySchalnat

GuySchalnat