Tried my first Auto-X this past weekend. I had the time of my life.

My tires were squealing and all over the coarse. (being a novice might have something to do with this. :smile: )

Anyone tried to Auto-X with the stock Pirelli performance run flats? And if so, what were your impressions and what were your tire pressures?



His, chile RED all over / Hers, EB UJ on top.

 

>>Anyone tried to Auto-X with the stock Pirelli performance run flats? And if so, what were your impressions and what were your tire pressures?

Hey, I just finished the SCCA Novice school yesterday. That's my 2nd event (first was a points event a couple of months ago) plus some mountain driving all done on the Pirellis.

First event was 38# cold all around. It felt more like I was on skates than anything--just sliding all the way around the course.

After riding in another MCOers MINI with the Dunlops at ~33# I lowered mine to 33 and went driving in the mountains. The traction felt much better, though handling was a little loose. I still had shoe polish on the tires & they never rolled over. (Polish was rubbed off up to the corner of the tread, but not the single band of tread on the sidewall. The rears obviously don't roll over nearly as much.)

My latest event I tried 36# cold, and then lowered them 2# after a couple of runs.

So wha's that mean? I'm still convinced that they're better with the lower pressure. After hard driving in the mountains (with 400 lbs of driver and passenger, and another 20 in gear in back) without any problems I'm confident that they're not going to roll off of the rim or anything.

One of the instructors that rode with me yesterday said that the tires were really limiting, and that times would likely drop a couple of seconds with Kumhos, etc..

FWIW, I really enjoyed them in the mountains, but was kind of frustrated with them on the AutoX track. Right now I'm trying to decide whether to stay in stock and go with 16x6.5 rims or buy 16x7 and get bumped to a different class.

HTH, Jeff

ps: Oh yeah--I had a blast in the AutoX school. ***Definitely*** try it, as you'll get a lot more track time, and instruction to boot. I'll post more later about the day.

 

Thanks for the feedback. Good to hear your impressions. :smile:

I started with 38# front and 35# rear for the first 3 runs. After the car sat in the sun for a while and the day heated up I re-checked my pressures and spoke with someone who knew what he was doing. We looked at the wear on my tires and lowered the pressure to 34# all around. My best time was after the adjustment. It may have helped,??? but still these tires are like heavy blocks of ice on the Auto-X.

I'm seriously considering lighter rims (currently have s-lites) and better tires.


His,Chile red all over / Hers, EB UJ on top.

 

no, no, no. You increase the tire pressure for auto-x not take it out. sheesh. I believe tirerack has suggestions for these tires. I ran mine with the pirelli's but kept the tire pressure the same. Next time i will definitely raise it a few pounds before going. Probably like 38 and 40.

 

I understand the way it's supposed to work, but those are my impressions. (You begin to doubt your own judgment when everyone's telling you that your perceptions can't be right!)

I got a good look at the fronts and took pressures cold yesterday. They settled at 35# cold (remember I was adjusting pressure warm) and looked like they were rolling over a little bit more than I previously thought. Almost to the edge of the tread that wraps around the side.

For street driving, mountain carving, etc. I've settled on 33# and I get consistently better traction. I tested the theory last night

I'm going to keep playing with the pressures to get more of a baseline. Remember that these sidewalls are a *lot* stiffer than normal tires, and I would presume that they're not going to deform as much as normal tires. I don't know how this affects traction and the goals for pressure. The only way I can think of being objective would be to take a consistent driver and get lap times.

Any other opinions or testing I'd love to hear.

Jeff

 

IMHO if what you want to do is understand how air pressures cause your Mini to react then go with big changes so you can notice them, during an autocross.

Particularly if you are only going to use your runflats with their very stiff sidewalls, it's very hard to get those to 'roll' over with small air changes, that's why they are runflats.

I use Yokohama A520's for wet conditions and as my daily driving tire, and when I ax them I put 40 front 35 rear.

I use Hoosiers when it's dry and the competition shows up, and I put 45 front and 35 rear. Helps the car rotate for my particular driving style.

I took the runflats off and put them in the garage. If you want better performance in autocrossing, IMHO lose the runflats....

FWDAugs