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10-21-2012, 04:49 PM | #1 |
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Drives: 2011 135i
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Location: In your streets, straightening your curves
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17x9 square set up; Dramatic handling improvement
Didn't find many examples of a square set-up using 17x9 wheels on the forum, so thought I'd share info & impressions.
Wheels: Beyern Bavaria S40 Tires: Michelin Pilot Super Sports 245/40ZR17 Front Wheel spacers: 5 mm Rear Wheel spacers: none Front camber: -1 deg Rear camber: -1.7 deg (Eibach Pro System springs, struts & shocks previously installed). Wheel/tire configuration suggested and executed by Butler Tire in Alpharetta, Ga. The wheels are rotary-forged resulting in an 8 to 10 lb. weight savings per wheel/tire combination as measured by my SAE approved bathroom scale. That is a ~16% to 20% weight savings over the 50 lb. OEM wheels with Nitto NT05's mounted. Some of that weight savings may be attributed to Pilot Sports' light weight construction. No real fitment problems. The front passenger tire will slightly hit the fender liner upon heavy suspension compression. If I understood correctly, they had to mess with the rear camber plates to dial in that much camber. I was a bit alarmed that you can actually see that much camber in the rear wheels. Butler Tire explained that the configuration would be considered an aggressive street set-up. Try it. You'll like it. Mikey likes it. The handling improvement is dramatic if not astounding. I'm no suspension dynamics ninja, but it is abundantly clear there is some next-level stuff happening. The suspension quickly takes a set and plants itself firmly and flatly. No drama. No delicate negotiations with the masses about distribution. Just turn in, point to the exit, apply power. An unexpected benefit appears to be braking performance. Even with a set of BMW drilled & slotted front rotors, the brakes would massively protest elevation descents. It appears the brakes are happier with the lighter wheels and didn't protest even when making back-to-back sorties through East coast elevations. Taller tire sidewalls noticeably contribute to more civil ride quality over harsh surfaces. Didn't expect how nice the wheels look in that they are understated and could easily pass as OEM wheels instead of appearing hoon-ish. Kudos to Butler Tire for their knowledge & experience bringing out the potential in cars like the 135.
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Michelin Pilot Super Sports / United BMW's Double-Secret Spring-less Performance Suspension Upgrade
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10-21-2012, 10:02 PM | #4 |
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@Black128i: Thanks, I like how things turned out. The previous set up with OEM rims & spacers was even more flush (pic below).
@631twentyeighteye: Haven't experienced any sidewall squirm with the taller sidewalls. The overall package is incredibly tight. It's my understanding that smaller diameter wheels is a trend for track cars due to lighter unsprung weight and lower tire costs without any performance degradation. I personally feel that the tire wall height-to-performance-to-style calculus has long ago capsized and sunk into a matter of pure style.
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Michelin Pilot Super Sports / United BMW's Double-Secret Spring-less Performance Suspension Upgrade
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10-23-2012, 03:33 PM | #5 |
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Drives: 2012 135i
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What brake package do you use? Are they the performance brakes or just the stock rotors? I'd switch to a similar setup for track only, but not sure about clearance for the rotors and calipers on the performance brake kit.
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10-23-2012, 06:04 PM | #6 |
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I'm running the BMW Performance rotors on the front. The rotors are the same diameter as the stock rotors, but are just drilled & slotted.
Rotary forged wheels have less material around the perimeter of the wheel and so has room for larger brake discs. If you are thinking about track time, the calipers are the real problem. The 135 calipers use plastic pistons. Search around the BMW forums and I think you'll find some posts about the calipers being destroyed by track usage.
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