JSpecMax

Hey, just wondering, what tire pressures do you guys run at the track? I imagine when pushed the max must have a crapload of understeer due to the fwd platform and heavy far foreward engine. I have never autocrossed my I30, but i used to hit the track quite often in my 94 civic. Sadly, i think my civic could have handled the autoX courses better than my i30 can, or maybe im just running the wrong pressures? Any advise is well appreciated!

BEJAY1

iTrader: (19)

I'll jump in first for auto-x pressures. 225/55/16 tires, between 50-60 front, 35-38 rear. Getting new 45 series soon - those will be way lower...

JSpecMax

Damn thats high. What rims, 16's? I had 36 front and 34 rear on my stock tires and rims, and i found the car skipping off of bumps and things during hard cornering. The fronts would just snowplow foreward - kinda scary. Also, ride quality suiffered greatly. I reduced pressures and noted better handling, but i was just wondering what the ideal setup would be. My max psi is 44, so i cant even imagine 50-60 up front. Also, dont you want the higher pressures in the rear so oversteer will be the tendency? There is already too much FWD mush, why make it worse by putting such high pressures up front?

BEJAY1

iTrader: (19)

Did you every try more in front (or droping the rear a bit)? That might help reduce the snowplowing and give you a bit faster steering response.

Driving styles vary but I found having 10+lbs more in front helps my 4th gen rotate around the corners.

Handling adjustments for competition

JSpecMax

thanks for the info, i'll check that link out too.

Norm Peterson

Thanks for the link, BEJAY1.

There are two schools of thought for getting a FWD car to rotate using tire pressure tuning. One is significantly to use less rear pressure than front (I think this works with the lateral stiffness of a tire as a function of internal pressure). The other is to use significantly greater rear tire pressure (which reduces the contact patch width and length of the rear tires).

If you seem to need upward of 60 psi in the front it might be worth trying the other path (drop the front pressures and run higher pressure in the rear).

Norm

BEJAY1

iTrader: (19)

You're absolutely correct. A similar discussion took place on another board recently. The front vs back depended much on the tires and vehicle. I am not the expert by any means. That's just what worked for me.

I'm about to change tire brand, size, grip etc. I'll start again from scratch on 8/25 and report back what I find out.