Taking X3 M40i to the track (DE) - help on wheels/tires

[mihalis]

I registered for a DE event at Club Motorsports in NH.

http://www.clubmotorsports.com/

I've done my share of DE's in the past, never in an SUV, but I was motivated after reading this article from MT.

https://www.motortrend.com/cars/bmw/...date-6-review/

I currently have 19's, with H Rated Run Flat Bridgestone All Season Tires (stock set-up), great for everyday driving, but don't really want to run them on the track as they really don't provide great feedback when pushed and don't feel reliable for track duty, especially for such a heavy vehicle.

I checked tirerack and for about $2K I can get 20" rims around just north of 23lbs each (stock 19" rims weight about 27.5lbs), and some really good tires as well Brigdestone Potenza S007A all around 245/45/20. According to the article, vehicle was set up with a staggered set, having 275 in the back and 245 in the front. Both my 330ci and 128i had a staggered set up, but I've read that for track duty it might be better having the same in all 4 corners. If that is the case, what if I went with 255's all around?

I remember when I ran my 330ci on Supersports and DT10 brake pads, it was just an amazing combo on the track, loved it, I know the X3 M40i will not be the same, but hey, it's better than no track duty!

Any help would be appreciated!

Thank you!

[eacmen]

Never ran an SUV on track before. But you generally want more sidewall on the tire not less. The tire itself acts as a spring, smaller sidewall equals stiffer ride generally speaking.

I would stick with your staggered setup until you really get to know the car on track. From the factory they design most cars to understeer since its easier to control for inexperienced drivers. If you do go square just be sure to research what will fit on the front, you might need to run spacers in the rear so the stance doesn't look wonky. With more rubber in the front the car will tend to tramline while driving on the road.

If I were you just get some decent tires and pads and let it rip and see how you like it. Then start trying to make decisions on what you want to change to the car.

[mihalis]

Never ran an SUV on track before. But you generally want more sidewall on the tire not less. The tire itself acts as a spring, smaller sidewall equals stiffer ride generally speaking.

I would stick with your staggered setup until you really get to know the car on track. From the factory they design most cars to understeer since its easier to control for inexperienced drivers. If you do go square just be sure to research what will fit on the front, you might need to run spacers in the rear so the stance doesn't look wonky. With more rubber in the front the car will tend to tramline while driving on the road.

If I were you just get some decent tires and pads and let it rip and see how you like it. Then start trying to make decisions on what you want to change to the car.

Thanks for the reply. I was going to have these as designated track wheels/tires as I plan on running 2-3 events per year. I'll stick to the set-up that comes stock if I got the 20" staggered setup and that MT ran on the track with some good summer sticky tires. I'll keep the 19's with run flats for everyday driving. When I had my 128i, i ran new decent tires at 2 DE's (one or which I dual drove the car with my brother in law) and they just got completely destroyed.

[Haifisch M3]

some organizations will not allow vehicles that are taller than wide but I just checked
and the X3-M is 186″ L x 74-75″ W x 66″ H so more of a cross over than an SUV

[eacmen]

some organizations will not allow vehicles that are taller than wide but I just checked
and the X3-M is 186″ L x 74-75″ W x 66″ H so more of a cross over than an SUV

Most of the manufacturer clubs (audi, bmw, porsche) will allow most if not all of their models on track. I was at an audi event and had a great time lapping a Q3 several times in a 30 minute session.

[mihalis]

Most of the manufacturer clubs (audi, bmw, porsche) will allow most if not all of their models on track. I was at an audi event and had a great time lapping a Q3 several times in a 30 minute session.

Trust me, not in my wildest dreams I have visioned I would be lapping an X3, and honestly for it's cost ($63K with destination, $49.5K after discounts), I would have purchased an M2 or my favorite, a GT350 (old school V8 with stick), but again, I drive a Pacifica everyday and this was the wife's car, she wanted nothing to do the GT350 or the M2, she likes her X3, and loved the power difference from her base to the M40. As mentioned, after reading the MT article, I was motivated to at least give it a shot. It's funny, one of my employees just got a Porsche Cayenne (base) with sport package, and from the factory, it come with 21's, 315's in the rear and 285's in the front!!! In case you are wondering, yes, my employee has the most expensive car in the work parking lot.