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      07-05-2008, 03:13 PM   #8
sayemthree
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Drives: ‘20 X3mC ‘20 Raptor ‘04 X3 6mt
Join Date: Aug 2007
Location: usa so cal , AZ

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Quote:
Originally Posted by swamp2 View Post
Someone should post actual weight numbers from the wheels, fronts and rears, 18s and 19s, and finally with and without tires. I seriously doubt the claim that 19s are lighter than 18s. As others have stated both the weight of the wheel and it moment of inertia are factors that affect the performance of a car with the wheels. The wheels have be be linearly accelerated like any part of the car that does not rotate (say a seat) but in addition they have to be spun up (angularly accelerated) which takes additional power.

Although I saw an old test report for the E46 M3 that showed some performance advantages (at least two of the following acceleration, braking, track times were improved) for the 18s vs 19s, I seriously doubt you can feel the difference, they are quite small. It is like saying you can feel a suitcase in your trunk in a car that weighs 3700 lb with 400+ hp. Not possible.
as stated - the 18 and 19's have virtually the same diameter so rotational inertia is not an issue. the 18 and 19 PS2 tires also are almost virtually the same weight so that would not affect inertia - if the 19 tire was one pound lighter than yes a slight disadvantage would occur as keeping the wieight closer to the axle is an advantage.

the wieghts of the two e92 OEM tires and wheels have all been posted here before. its clear the 19 tire/wheel wieghs less than the 18 tire wheel combo.
see link below.

as far as e46 wheels? the e46 rear with a DUnlop SSR is 52 pounds.
the e92 rear 19 inch wheel with PS2 mounted is 51.4 pounds. my front e92 19 wheel was 47 pounds.

http://www.m3post.com/forums/showthr...ghlight=weight
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