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So, Danville will be the debut of Richard's old Kosei's/Falkens (now ghetto-fab flat black) on my wife's mini. Its a very different wheel/tire combo than I've ever used before, and I don't know where to start with air pressures.

I'm used to wide tires crammed on a rim thats too narrow (225 BFG G-force sports on a 7" wheel is what I have on the mazda), but I realize I'm dealing with a different beast here. I run 44 F 40 R (44 is optimum grip, 40 in the rear is for balance) on the mazda, and it seems to work, but I know I wanna go with lower pressures for this setup. I just don't know how much lower.

They are 205/40-16 Falken's on 7.5" wide wheels. Not only is this my first "stretched" wheel tire combo, but its also my first set of Falkens. I'll worry about tuning for balance later, right now I just want to know where to start to get optimum grip. The car is running on stock (camber challenged) sports suspension. Any suggestions (whether for my mazda or for this setup) are welcome. thanks!

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2012 MX-5 Sport SUV

Brice,

Can't predict what they will do on the Mini, but on the Civic, IIRC I was using 42F and 36R (or something close to that). Good luck with the wheels/tires. Hope they work as well for you as they did for me!

Richard

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Richard Casto
1972 Porsche 914
2013 Honda Fit Sport
2015 Honda Fit EX
http://motorsport.zyyz.com
Money can't buy happiness, but somehow it's more comfortable to cry in a Porsche than a Kia.

I used to run 45f/35r for FWD cars, then gradually worked down to about 40-42f/35-37r. This seamed to work for the ITR, 1st gen crx, and the civic. If you want to keep balance, drop f/r the same amount.

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Phil... Now I miss the ITR and the M3!!!
1990 Honda Civic SI

Brice when we ran azenis we were 42f/38r. As you can see everyone runs something different. I normally like to run lower pressure than Gwen, so pick a ball park number and let Brantley drop the pressure until she feels The handling is right for her. There's no magic # for any one type of car.

wow, I was expecting lower answers than what I got here. She liked the balance of the car on her runflats at 36/36 (runflats don't need much extra pressure at all, the sidewalls are absolute rocks). The reason for staggering the pressures is tuning for balance, correct? Guess we'll start at 42F/40R, and drop them from there as necessary. Thanks guys.

While we're on the topic of tire pressures, I set the fronts on my mazda at 44psi b/c thats the max pressure listed for the tire. Is there any great harm in exceeding that pressure for autocross (assuming I continue to check pressures after each run). I think they could use a little more air to keep from rolling over, but stopped at the max pressure listed on the tire. Basically, is the max pressure listed on the side of a tire the max COLD pressure?

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2012 MX-5 Sport SUV

I used to run my Azenis in the 32-38psi range F/R depending on the grip level (lower psi for slick surfaces.) I found that they were fairly insensitive time-wise to the actual pressure but they would definitely feel different. Of course this was on a relatively light car with plenty of camber but I was also running a taller sidewall with a less optimal wheel width. Your starting point seems to be reasonable but I wouldn't go much above that unless your tires are rolling over really badly.

And yea, generally the staggered pressures are for balance. I'd much rather try to balance the car with suspension but if you're already close, tire pressures are a great quick fix. I also prefer going lower than optimal in the rear to reduce grip for rotation as opposed to going higher. That tends to be a personal preference but I find the lower pressures to be more forgiving.

Jim

Yeah. When I run on Azenis (schools and HPDEs) I'm usually around 36 all the way around. I think at CMP I was at 34 actually.

Granted this year I have shocks helping me with balance, but I'd been going higher in the rear when I was on OEM shocks last year. It seemed to me the handful of times early on when I tried lower pressures in the rear tires, that I really had to chuck the car around to get it to rotate. Still even with higher in the rear, I was still being less smooth, but it seemed to work for me.

That seemed to work decently.

YMMV IMHO, Etc and so on.

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Not spectacular just decent.
I'm not sure what I'm driving.
Maybe an ITR in DS.
Or half-assed STX prepped 330.