This weekend was my first time racing my new MCS. I have been watching these threads and asking questions about tire pressures for the run flat tires. I am running the sports package with 17" rims and the Pirelli run flat tires that many orther people are probably buying with their cars. Anyway I have seen much conflicting advise for front/rear pressures so I thought I would give my two cents. By the way I have been racing a 914 against the Miatas the past 4 years with much success until the engine went south, so I have some experience.

I called Alex/Dan at Tire Rack for advise and he suggested 34 Front and 37 rear.
I also got some advise at the track from some successful racers and they suggested 40 front, 34 rear. Here are the results for the day at both pressures:
Start of day 40F,34R
51.486
51.467
52.199
52.616
All of these runs produced extreme understeer(push)
After the break I changed the pressures to 34F,37R
Here are the results:
50.916
50.026
49.811
49.107
At these pressures I could start to keep a line through the corners.
I hope this information will be of some help.
I did decide to get new tires sooner than later.(Much sooner!)
I also know that I need new wheels but they must wait until next season.

 

Thanks for the info! Should give me a good starting point on pressures for the track - my first drivers school in the MINI is May 1 (although I may bump them up a bit, I'll try a similar front/back ratio).

Anybody have thoughts on runnig the performance run-flats on the track? All my $$ this season went for race tires for the racecar, none left for race tires for the MINI....


_________________
'03 MCS BRG/W, 3 option pkgs

 

Sorry,
I forgot to mention that on the second session I reduced the front pressures 2 lbs on each run. I think that really helped the understeer and the lower times. I just ordered Kumho MX 215/17's for next time. I went with these after looking at Tire Racks comparison tests. They looked like the best bang for the buck. I'll let you know how they work in a couple weeks.

 

Sounds like the run-flats respond to pressure changes like the old BFG R1s. You would think that in an understeering FWD car, you would raise front pressures to give you more grip and lower the rears to help them "break away" a bit earlier. Sounds like the run-flats (and the old R1s) are running similarly couter-intuitive: lower pressure = more stick. Glad to see my R1 experience won't go to waste and I'll keep those rear tires nicely pumped up to try to tune a little "looseness" into the car...

 

eight runs in one day, I'm jealous!! How did you fair against the competition?

 

>>eight runs in one day, I'm jealous!! How did you fair against the competition?


It was a test and tune day. It was also my first time racing a front drive car (914 before). My times were about the same as the Miatas and 4 sec. behind the WRX ace on Kumho DOT tires. I need more seat time and have new tires ordered. Kumho MX 215/17's. I think with the new tires I should be about 2 to 3 sec. faster and have another 2-3 sec. with better driving technique.

 

How did your runflats hold up to a day of autocross? I'm looking forward to autocrossing my MCS, but I don't want to shred my daily driver runflats in one day. I'm thinking about getting a set of wheels from Randy at MINI Motorsport, but I won't have the cash by the time the first autocross rolls around.

 

Reply to Jimmer0
The tires held up fine. I didn't notice any undo wear after 8 runs. I also plan on getting new wheels and DOT tire eventually but can't change tire now because of a shoulder injury. Make sure your new wheels are legal if you want to run G Stock. I found the pressure changes made a big difference in the understeer. I have another xcross this next weekend with my new Kumho tires if it doesn't snow too hard for me to get down to Reno. Let me know how you do.

 

Greetings
Thanks for the advise and sharing your experience with the rest of us MINI novices looking forward to autoX competition!!
Ron
'03 MCS PS/B

 

wow great info!! thank you for posting I do hope that this next auto x is my LAST ONE on my damn run flats hopefully I will have new rims/tyres by next month!!

 

Hi Jimmer and fellow autox'ers:

My autox this past weekend at a Sacramento Region, SCCA San Francisco Chapter was quite a emotional rush. Two day event. My 1st for my MCS with 17"Dunlop runflats. I followed Tire Rack recommendations of 34# in Front 37# in back. I did not get rollover scuffing at all onto the sidewall. Sunday Fun runs I drove like a madman and took 2.5 seconds off my best run. Found my limits with the Dunlops and the SLite #25 rims. I was at least 2-3 seconds off being competative with comparable stock drives in G Stock. The truly fast cars had "to kill for 16" Rims" and Z or AA grip rated tires . The new mazda m3p? was probably best in class. But it was a sponsored car with an experienced driver.

I had only two days of autocross experience last year before the weekend event. 1st gear is really a killer, so much torque, wheel spin and acceleration, ( with lots of noise) coming off slow corners into short straightaways. I never got out of 2nd gear, but learned quickly to use 1st whenever possible taking it to 7000 is better than short shifting which many cars did that had too little torque to put the car at the limits.

I could go on for another 2000 words.

Tires, the run flat dunlops did well, treadwear rating of 180, no squeeling rounding slow or fast tight corners, grip was great, even in understeer, the dunlops kept trying to turn in on the hot corners, heavy throttle brought the front back on line. ( I didn't knock over any pylons this weekend). If you have an MCS, drive it to find the limits (With DSC OFF) and then finesse it smoother exceeding your known limits, I've yet to see a MC do a 360 spin coming into a hot off camber corner.

I fully expect to run the dunlops into oblivion during the next 8-10 days of autox. AA or Z compound tires would assist in obtaining some extra speed somewhat, but #13 rims instead of the #25 S Lites is the better choice in staying G Stock.

Driving the MCS near the limits with DSC off should be illegal as it is such sinful screaming excitement.

But, then again what do I know, all the above is my seat of the pants first experience, I have a long way to go, first I will drive fasert and smoother this season staying in GS, then Xmas comes, (rims and tires).

:smile: GO FOR IT

 

Miniron - Greetings!!
Thanks for sharing your experience! Great fun !!
Best Regards,
Ron