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-   -   Crazy question for you lucky m3 owners (http://forum.e46fanatics.com/showthread.php?t=918714)

cyberlando 04-29-2012 06:57 PM

Crazy question for you lucky m3 owners
 
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?

cyberlando 04-29-2012 07:00 PM

does the m3 have a harder time breaking the rear end loose with 19?

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

LittleChrist12 04-29-2012 07:01 PM

Ride quality improves (more sidewall), weight goes down (smaller wheel), and the potential to bend a wheel goes down as well. Tires are also cheaper.

Hollywood516 04-29-2012 07:15 PM

Quote:

Originally Posted by LittleChrist12 (Post 14343995)
Ride quality improves (more sidewall), weight goes down (smaller wheel), and the potential to bend a wheel goes down as well. Tires are also cheaper.

Yep.. what he said..

Drew@Swift Motorworks 04-29-2012 07:26 PM

Quote:

Originally Posted by cyberlando (Post 14343992)
does the m3 have a harder time breaking the rear end loose with 19?

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

youre asking for the wrong reason :tsk:

go google unsprung weight

Blocked Out 04-29-2012 07:28 PM

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

Blocked Out 04-29-2012 07:29 PM

Quote:

Originally Posted by Drewdown (Post 14344085)

go google unsprung weight

lol, I can bet that only 5% of M3 owners know what that is

dmax 04-29-2012 07:32 PM

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!

cyberlando 04-29-2012 07:44 PM

Quote:

Originally Posted by Drewdown (Post 14344085)
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??

HiHoBrian 04-29-2012 07:57 PM

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.

cyberlando 04-29-2012 08:01 PM

Quote:

Originally Posted by HiHoBrian (Post 14344203)
The CSL has 19's....because it can.

thats not helping at all

Blocked Out 04-29-2012 08:06 PM

Quote:

Originally Posted by dmax (Post 14344109)
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 .

ImolaSix 04-29-2012 08:18 PM

Quote:

Originally Posted by dmax (Post 14344109)
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! :(

cyberlando 04-29-2012 08:24 PM

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

ImolaSix 04-29-2012 08:29 PM

Quote:

Originally Posted by cyberlando (Post 14344316)
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".

Blocked Out 04-29-2012 08:35 PM

Quote:

Originally Posted by cyberlando (Post 14344316)
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

Blocked Out 04-29-2012 08:38 PM

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

ImolaSix 04-29-2012 08:42 PM

Quote:

Originally Posted by Blocked Out (Post 14344356)
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

That'd be great! :woot:

cyberlando 04-29-2012 08:43 PM

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!

cyberlando 04-29-2012 08:44 PM

might just throw them on the scale next time i have the tire off the rim.


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