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[Kim Schwartz]

I want to get a set of wheels/ tires for summer and occasional track use for my 128i with the sport package. I am thinking of either staggered 215/40-18 Front with 235/45 or 245/40 Rear or just using 225/40-18 in all four corners. Which would be most neutral in handling balance? I ask as the square setup seems like it would be most neutral but I also drive a 2007 Z4 coupe with the sport package on a traack and it has a staggered setup, 225 f and 255 r. and it feels quite neutral even with no traction control. I have been thinking myself into a corner on this and could use some objective insight. thanks in advance.

[Eddy@ApexWheels]

do you plan on doing any other modifications to the car such as suspension/camber plates? down sizing your rear tires to a 225 on a car with 300lbs of torque is not ideal, and not a worthy trade just for a square setup.

Without negative camber up front you'll be wasting what ever width tire you run up front. BUT, if you dial in negative camber then not only will you be increasing front grip significantly, you'll also be providing the necessary room to fit a wider front tire?

I would ask yourself what you're willing to do to the car, before you spend $1500-2000 on wheels/tires.

[pixelblue]

I have been thinking the same but I can't decide whether I should go 17 or 18. I am considering getting the arc-8 for next years track season. I have camber plates and I was thinking 245 all around. what do you think paintpro21? thanks in advance

[mineo77]

for track you want as much rubber to the road as you can get, so a square set up will let you run bigger tires up front. I run a square at the track for wheels, but my tires are still staggered since i cant squeeze a 265 up front for obvious reasons. 245 f, 265r...but this will also depend on tire manufacturing and sometimes you will need to adjust accordingly. Yes you will need camber adjustments to run this set up and small spacers up front.

[Kim Schwartz]

Originally Posted by paintpro21

do you plan on doing any other modifications to the car such as suspension/camber plates? down sizing your rear tires to a 225 on a car with 300lbs of torque is not ideal, and not a worthy trade just for a square setup.

Without negative camber up front you'll be wasting what ever width tire you run up front. BUT, if you dial in negative camber then not only will you be increasing front grip significantly, you'll also be providing the necessary room to fit a wider front tire?

I would ask yourself what you're willing to do to the car, before you spend $1500-2000 on wheels/tires.

As it is a 128i sport package, the stock set up is 205/50-17 front and 225/45-17 rear, so the square setup would be basically using the same with as the rear tires on the fronts and it only has 210 lb. ft. of tourque. This is primarily a street car so I hope to do as little as possible to change it. But 18' wheels with appropriate tires would be good...and maybe swaybars. The Z4 coupe is the better track car in general.

I was wondering if the square setup would yield a more neutral handling balance/ less understeer/ or actually tend toward oversteer? The Z4 is a staggered setup and pretty neutral but obviously a rather different car.

[Kim Schwartz]

Originally Posted by pixelblue

I have been thinking the same but I can't decide whether I should go 17 or 18. I am considering getting the arc-8 for next years track season. I have camber plates and I was thinking 245 all around. what do you think paintpro21? thanks in advance

I am going to go with 18" wheels as they should quicken the steering response. Also, as the stodk wheels are a little on the heavy side I can get 18" wheels that are lighter than the stock 17" wheels. And if I use non run flat tires I can save over ten lbs per corner with the 18" setup over the stock 17" set up. To me it sounds like I have everything to gain and nothing to loose with the 18's.

[LA-Bimmer]

Originally Posted by pixelblue

I have been thinking the same but I can't decide whether I should go 17 or 18. I am considering getting the arc-8 for next years track season. I have camber plates and I was thinking 245 all around. what do you think paintpro21? thanks in advance

I run the ARC-8s with 245 BFG R1s on each corner with Vorshlag plates -2.7 front, -2 rear. Much more neutral than when I ran a 245F/265R in the R1s. Took about 2.2 seconds off the lap times on a 2.9mile course. You can really feel the reduced unsprung weight vs. the stock wheels

[pixelblue]

Originally Posted by LA-Bimmer

I run the ARC-8s with 245 BFG R1s on each corner with Vorshlag plates -2.7 front, -2 rear. Much more neutral than when I ran a 245F/265R in the R1s. Took about 2.2 seconds off the lap times on a 2.9mile course. You can really feel the reduced unsprung weight vs. the stock wheels

thanks man! I am guessing you are running the 8.5's? also what about running on 17's? any advantage?