Wheels

[m3f_96BmwCosmo_c44c0f570d]

our stock wheels weigh about 21 lbs in front and 24 in back or someting around their. i was wondering if i went with a bbs rk which weighs 16.5 if i would feel a difference in acceleration or anything versus a 24, 25 lb wheel. is the weight that big to notice a difference? i was thinking of doin 18" wheels but do not want to sacrafice any of my performance on top of that i have h&r coilovers which are are adjusted to the lowest setting and dont want to worry about rubbing. any help is appreciated. thanks alot guys

[m3f_Max M3]

"Feeling" the difference is fairly subjective. However, losing ~24lbs of unsprung weight is significant so I'd have to say you're likely to feel that!

[m3f_96BmwCosmo_c44c0f570d]

what do you mean by unsprung weight? are you refering to my suspension?

[m3f_kchildre]

He means the wheels are not supported (sprung) by the suspension. Unsprung weight is a performance cars enemy. It inlcudes the wheels, tires, brakes, and lower suspension components. That's one of the reasons you'll see performance cars go with lightweight wheels, aluminum hub rotors, calipers, and the lower control arms (at least). A rule of thumb I've heard is one pound of unsprung weight saved "feels" like five pounds of real weight. Aka save 20 pounds on the wheels and the car should feel 100 pounds lighter.



I put RK's on last year from the OEM wheels and felt a difference right away. But like they said "feel" is subjective.

[m3f_99DakarM3_146594ecf1]

It is weight directly attached to the drive-line (in everyday terms). Every pound of unsprung weight you loose is a percentage of power gained back b/c the engine does not have to work to move that weight anymore. Reducing the weight of driveline items - flywheel, driveshaft, etc... will help "free up" some of the power the engine is already making.



This is the reason why some BBK's actually reduce the acceleration, etc... of a car. The larger rotors actually add more weight to the driveline resulting in decreased performance (not in stopping distance of course).



I'm sure their are others who have a much more technical answer, but this is it in non-technical terms.

[m3f_Ty Vil_fe6451789c]

Your stock wheels are closer to 23 lbs each. You can get 18" Fikse's at like 18 lbs each.

[m3f_vinnymac_842df9028e]

I ditched my stock wheels and went with 17"x8.5" SSR Comps (15lbs/ea) and put on 235/40/17 Toyo T1-S's (21.4lbs/ea) and the car feels a lot more nimble than it did before.



I also ditched my 18"x8.5" AC Schnitzer Type III's recently and picked up a set of 18"x18.5" SSR GT2's (19lbs/ea) w/ Michelin Pilot Sport A/S (~26lbs/ea). The car should still remain pretty nimble compared to stock.



What you "feel" is pretty subjective, but you should notice a difference with less unsprung weight.



Good luck.

[m3f_M3_AV8TR_09262c9aba]

If you go from 17's to 18's your car will accelerate slower regardless of how light they are unless you change the differential to a higher ratio.

[m3f_96BmwCosmo_c44c0f570d]

thanks alot for the responces evreryone you have been a lot of help

[m3f_eXpLiCiT_4_fb030f9c5e]

I ditched my stock wheels and went with 17"x8.5" SSR Comps (15lbs/ea) and put on 235/40/17 Toyo T1-S's (21.4lbs/ea) and the car feels a lot more nimble than it did before.



I also ditched my 18"x8.5" AC Schnitzer Type III's recently and picked up a set of 18"x18.5" SSR GT2's (19lbs/ea) w/ Michelin Pilot Sport A/S (~26lbs/ea). The car should still remain pretty nimble compared to stock.



What you "feel" is pretty subjective, but you should notice a difference with less unsprung weight.



Good luck.



You got any pics of your car with the GT2's? Ive been considering those latley but I've only seen them on TireRacks website. Thanks.