The chalk mod

"Turner950s" (Turner950s) 10/26/2013 at 04:34 • Filed to: None

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Busted out the chalk and dialed in at 35psi in front, 30.5psi in the rear. Previously, I was running 32 front and rear for regular road use. This adjustment gave a pretty good balance between over and understeer.

(For those who don't know, you can mark the tread and sidewall of your tire with a line of chalk and corner quickly to see how much of your tread you are using, and whether you are rolling onto the sidewall at all. Then, adjust the tire pressures appropriately.)

After sorting it out, I took out the spare tire, jack, lug wrench and my ~30 piece socket set from the trunk, which total at least 30lbs. The added lightness in the back with that same pressure setup seemed to give me much more oversteer, especially under braking as the tail end lifts up a little more.
How it felt:

All in all, this was a lot cheaper and easier than buying and installing a brake proportioning valve. 10/10 would recommend.

McSchmalex > Turner950s 10/26/2013 at 05:21

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I'm not impressed unless you get Ferrari to lend you a F12 and 5 sets of tires.

You can blame Chris Harris for my high standards.

lepie > McSchmalex 10/26/2013 at 07:14

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I could probably arrange for a F(iat)1.2 and 5 sets of space savers.

BKRM3 > Turner950s 10/26/2013 at 08:29

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Call me crazy but if you're looking for oversteer don't you want higher psi (a firmer tire) in the rear and lower psi (a grippier, more compliant tire) in the front? Your adjustments seem counterintuitive.

liquid_popcorn > lepie 10/26/2013 at 08:39

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9/10, would still pay to see.

Turner950s > BKRM3 10/26/2013 at 15:17

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I was going off of this guide, which explains it such that:

-The graph of tire pressure vs. grip is a "mountain shaped" parabola; if you're over or under the proper PSI you have less grip
-When trying to decrease grip in the rear to balance out handling, it's better to make the PSI lower because that way you retain more traction for putting the power down (in a RWD car), but still keep the tail loose when cornering.

I am by no means an expert. And yes, I am going off of what some random person on the internet said.

BKRM3 > Turner950s 10/26/2013 at 15:56

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Yeah I mean I don't know either. The only time I play with my pressures is watching hot pressures at the track. Don't want to roll over the sidewall past the indicators. Beyond that all my knowledge comes from Forza lol.