This will be our first year with a Mini to run in autocross. We are novices (I ran 3 days last year, my wife 2 times) and we are on a budget so going to get Falken Azenis RT-615’s to run only for autocross on our 16" x 6.5” Monza wheels. Planning to get the 215/45R 16 if they arrive in time, or 205/40R 16 otherwise.

What would be good starting pressures?

Also, is there a good primer somewhere that tells what to look and feel for to tell if you got it correct, and how to make the proper adjustments for the Mini in pressure? Or make this a good thread on the topic - please share your knowledge.

From what I can tell from other threads air temperature, type of surface, any moisture can all influence what pressure to run. Does street tire vs. R-compound matter? Does the size of tire matter? I read somewhere about putting chalk on the sides and see what rubs off to tell if you are rolling over on the tire – good idea? We have a tune up day in a month so just thinking ahead.

Thanks in advance,

Rollin & Theresa

 

I used to run the RT-615's (and the RT-215's before that)... I used to use 36f/34r, which helped keep the rear end in line on my car (rear swaybar and camber plates).

Before that, being totally stock, I found that 35 all around was a good starting point while learning the car back in early 2003 - and then, adding a bit more in the rear would help the car rotate - like 34f/38r.

Chalking the tires is a useful practice - take some sidewalk chalk and start on the tread and wrap it around the shoulder of the tire and onto the sidewall in a couple places on each tire. If the chalk is worn off the tread and right to the shoulder, the tire pressures are set well. If it's worn off around the shoulder, you need a bit more air because the tire is rolling over onto the sidewall. If it's worn off only on the tread and NOT to the shoulder, you need to lose some air... I suggest 2 psi bumps to fine tune it...

 

I usually run higher pressures. Rollin, especially if you're going to be starting at Waterloo (concrete), I'd put a little extra in there. It's easy to bleed it off.

I'd say put 45 psi in the front, and chalk/shoe-polish the tires. Just keep dropping the pressure every run until you're wearing down to about where you want to be. Since you have 2 drivers, you'll have plenty of runs to play.

But I normally run 42-44 psi in front, and 35-ish in back, depending. In the early season (aka COLD and damp part of the year - we've had snow at autocrosses in MN before), I'll sometimes run high 20's in back. I think the Mini heats up the front tires a lot faster than the rears, and it can get squirrely.

Pat Washburn drove my Mini once on the street tires last summer, and he said to put 50 psi in the front.

 

I'll have to check my notes from last season, but IIRC I was running 42-45psi in front and 52-55 psi in the rear in my HS MC on 205/50-15 Kumho 710's. If I can get the rear camber set closer to 0° this year I'll probably drop the rear pressures down a little bit.

-Keith