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Discussion Starter · #1 ·
Okay i realized more and more i read that most m3 owners are going towards the 18' rims rather than the 19's!!

i mean of course there is two big 20' m3 rims owners should shoot themselves but at the same time, what exactly is the reason behind choosing 18 9.5 over 19 9.5??

advantage and disadvantages ?

is it just taste?
 

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Discussion Starter · #2 ·
does the m3 have a harder time breaking the rear end loose with 19?

*not a m3 owner so cant really experiment myself* :facepalm:
 

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Personal choice on looks is is number 1, then its about cost , then reliability .

The diameter and width of the rim or tire has nothing to do with breaking the rear end loose . Even weight was no relationship with size
 

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Smaller means greater acceleration too. If the two wheels, 18 and 19 weigh the same, the smaller diameter of the 18s is, in effect, the final gear. You'd have greater acceleration, though a slightly lower potential top speed.

If I raced an identical car to mine with 17s, I'd win...coz I'm on 16s. Also, the more weight you have further from the axle, the more power it takes to move it...or something like that. I didn't take physics, but I did stay at a Holiday Inn once!
 

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Discussion Starter · #9 ·
youre asking for the wrong reason :tsk:

go google unsprung weight
woww good info broo, i will admitt that i never heard of this before!!

but if that is the case why does the m3 csl the competition level m3 with all its glory Come with 19's??
 

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One way to understand how two rims with the same weight but different diamaters would affect performance is to take a "thing" and tie a string to it. Then twirl it around in a big circle and then smaller diamater circles. The different forces you need to get the same rpm is what your car has to deal with.
The CSL has 19's....because it can.
 

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Discussion Starter · #11 ·

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Smaller means greater acceleration too. If the two wheels, 18 and 19 weigh the same, the smaller diameter of the 18s is, in effect, the final gear. You'd have greater acceleration, though a slightly lower potential top speed.

If I raced an identical car to mine with 17s, I'd win...coz I'm on 16s. Also, the more weight you have further from the axle, the more power it takes to move it...or something like that. I didn't take physics, but I did stay at a Holiday Inn once!
Doug, the smaller rim diameter is accommodated by higher sidewall on the tire. Regardless if you have 15s 16s or 18" rims, your overall diameter is still identical , which is 25" for E46 Non-M . For non-M E46 wheel tire combo must be 25" +/-2%.

For M3s the overall height is 26" +/-2%

Also, there are 20" rims that weigh less then 18" rims, and some 17" rims that weight more then 19" rims , see where Im going here ? You cant just say because this rim is bigger it automatically weights more then a smaller one .
 

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Smaller means greater acceleration too. If the two wheels, 18 and 19 weigh the same, the smaller diameter of the 18s is, in effect, the final gear. You'd have greater acceleration, though a slightly lower potential top speed.

If I raced an identical car to mine with 17s, I'd win...coz I'm on 16s. Also, the more weight you have further from the axle, the more power it takes to move it...or something like that. I didn't take physics, but I did stay at a Holiday Inn once!
Usually the overall diameter of the wheel stays the same because a smaller rim demands a larger sidewall. But, I do agree that the larger rim will add more mass away from the axis of rotation which will hinder performance.

Edit: Damn, Blocked Out beat me to it! :(
 

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Discussion Starter · #14 ·
so over all the diameter needs to be the same, but for weight saving and performance reason you'd rather have more rubber than metal? since rubber is lighter

is that about right
 

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so over all the diameter needs to be the same, but for weight saving and performance reason you'd rather have more rubber than metal? since rubber is lighter

is that about right
Not necessarily. It all comes down to the rims. You can have 19" rims that weigh less than 17" rims. Chances are they're going to be really expensive. You don't want too much sidewall because it reduces steering response when trying to get the car to change direction quickly. The larger sidewall of a 17" rim will flex more than the sidewall on a 19".
 

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so over all the diameter needs to be the same, but for weight saving and performance reason you'd rather have more rubber than metal? since rubber is lighter

is that about right
Depends what kind of racing or what kind of performance you need. Its a very broad topic and the discussion is pretty much endless .

Why is performance so important to you? You plan on performing ? If so ,I want first row tickets :D
 

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ImolaSix, we need to do a photoshoot together , our cars are so alike and I love it. As soon as it gets nicer I'll be planning a shoot
 

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Discussion Starter · #19 ·
i wonder how light 19's get nowa days, for that matter i wonder how light mine are?

i bought the car with csl replica's not sure what brand or anything but when i powder coated them they were pretty light!
 

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Discussion Starter · #20 ·
might just throw them on the scale next time i have the tire off the rim.
 
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