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[b1aze]

Originally Posted by simianspeedster

What's up Mikal?

Could you please elaborate on your comment about 17s helping with gearing and making the car feel quicker?

I recognize that a lighter wheel/tire combo will reduce the effort required to get rolling and the reduced unsprung mass has many benefits, but I'm not clear how wheel size affects gearing and quickness.

Assuming a constant tire diameter and combined wheel/tire weight, is there some other performance advantage to 17" rims that I'm missing?

Regarding the suspension, I'm planning to order the "factory" Performance Suspension (which I understand is installed at the port) because I want to keep it simple and keep BMW on the hook for everything.

You are 100% correct. Assuming one does not change the overall rolling diameter, you will see no performance increase from going with a 17" wheel over 18" wheel, assuming weights dont differ drastically. Rotating mass is rotating mass. Its all still centered around the axle.

I like the BMW performance suspension also, i plan on getting the setup soon.

[simianspeedster]

Originally Posted by John_01

I suggest getting 225/40 front, 245/35 rear, then get M3 front upper+lower arms for extra camber. Dinan camber plates are another alternative for a nice street setup. If you want to reduce understeer, a little negative camber works great!

Definitely get the performance suspension from the factory. I think you will love it (after getting rid of the runflat tires).

Thanks for the advice. For starters, I'm going to keep the setup fairly "factory" with the addition of the Performance Suspension as part of the order -- I'm getting a quote from my dealer now. If that's no sufficient for some reason (I think it will be for my needs), I'll keep modding.

I've decided that the ZED package doesn't make sense for me. The BMW wheels that come with the package are probably quite heavy, so I'm going aftermarket, likely Apex Aero 7 which look great to me and are quite light.

I'm still on the fence about square or staggered. I understand that BMW always defaults to staggered setups when sports packages/suspensions are added, but I just don't see the point of a staggered setup on a 128i and I'd prefer to be able to rotate my tires. 18x8 and 225/40-18 all around seems like enough tire for a BMW, and I believe it will provide better balance and turn-in.

I see you have a 135i, so it makes perfect sense to me why you'd want the wider tires in the rear for more traction, but I'm struggling to see the value in a 128i. Then again, I feel like I'm bucking the trend.

[simianspeedster]

Originally Posted by b1aze

You are 100% correct. Assuming one does not change the overall rolling diameter, you will see no performance increase from going with a 17" wheel over 18" wheel, assuming weights don't differ drastically. Rotating mass is rotating mass. Its all still centered around the axle.

I like the BMW performance suspension also, i plan on getting the setup soon.

Cool -- I'm leaning towards 18s. I usually don't care too much about cosmetics -- function over form, I say -- but in this instance, I do prefer the look of 18" rims and I think the ride quality will be OK once I ditch the runflats.

Odd reality: the ride quality on my 335i Coupe with M-Sport (i.e. sports suspension and low profile 18" performance runflats) is significantly better than my wife's E30 328i with the standard suspension and higher profile luxury runflats. Go figure!

[John_01]

Originally Posted by simianspeedster

I'm still on the fence about square or staggered. I understand that BMW always defaults to staggered setups when sports packages/suspensions are added, but I just don't see the point of a staggered setup on a 128i and I'd prefer to be able to rotate my tires. 18x8 and 225/40-18 all around seems like enough tire for a BMW, and I believe it will provide better balance and turn-in.

I see you have a 135i, so it makes perfect sense to me why you'd want the wider tires in the rear for more traction, but I'm struggling to see the value in a 128i. Then again, I feel like I'm bucking the trend.

With standard wheel alignment you will probably be happy with a set of 225/40 extreme performance tires all around and save some weight too. With lightweight aftermarket wheels it seems sensible and practical for street use. You can still adjust the camber within normal limits to get a fraction of a degree more on the front. Non-staggered tires are popular for the track, but you better use some caution if you do as the 1 series sometimes lacks stability on the rear end when not using DSC.

[simianspeedster]

Originally Posted by John_01

With standard wheel alignment you will probably be happy with a set of 225/40 extreme performance tires all around and save some weight too. With lightweight aftermarket wheels it seems sensible and practical for street use. You can still adjust the camber within normal limits to get a fraction of a degree more on the front. Non-staggered tires are popular for the track, but you better use some caution if you do as the 1 series sometimes lacks stability on the rear end when not using DSC.

Thanks, John. I'm fairly set on my configuration. I'm going to go with 18x8 Apex Aero 7 wheels with 225/40-18 Michelin Pilot Super Sports all around. I can't imagine that combo won't do the job with regards to handling, ride quality and weight savings. Also, I always leave DSC on (no track driving...yet).