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[Kunman]

So its an undisputed fact now that 17s do fit on our (stock) cars.


Apex Arc8 17x10

I am now very tempted to go for a 17 setup....but hat are the benefits of running a 17 inch track setup vs the much more common 18 inch set up? And what about usability on the street?

My conjecture (on the ARC8 17s alone):

pros:
handling, acceleration and breaking will improve due to a smaller rotational diameter
cheaper tires (350/set of of sumitomos DD tires)
355mm BBK fits
Low weight
comfort

Cons:
apparently some suspension kits will not fit without spacers
does not fit 380mm BBK
limited street tire selection

unknown:
effect of thicker sidewall

[4corners]

Two Michelin PSS 245/45/17 is $110 cheaper than two 245/35/19.

[Sandye90m3]

This is the first time I'm seeing 17"s on the E9X.

I was about to say "love the meat" unconsciously but that could have a very, very different context lmao

[pbonsalb]

I doubt the handling or acceleration will improve compared to Apex ARC8 in 18 inch with the same brand and width tires. The rotational mass difference will be very slight -- just a few pounds per corner. The softer sidewalls will give more, dulling handling.

It is not like BMW's best handling package uses the smallest wheels. It uses the largest wheels.

Cost wise, the 17s have the advantage. And most people probably would not notice the slight loss in handling -- or any miniscule gain in straightline acceleration. I am sure I would be happy running 17s, especially with the rough roads you fine in many parts of the country these days. They would also be a great choice for snow wheels. But I already have ARC8 in 18 x 9.5/10.5 for summer and snows on the stock 18s.

[SYT_Shadow]

I use 17 ARC8s for the track, 18 ARC8s for the street

I find the 17s look just fine in that concave design

[smmmurf]

That is awesome, thanks for sharing!

[Kunman]

Originally Posted by SYT_Shadow

I use 17 ARC8s for the track, 18 ARC8s for the street

I find the 17s look just fine in that concave design

Reasons for using 17s on the track? And why not use 17s on the road as well?

[4corners]

I remember reading that the testing of the E92 M3 before release back in 07, was doing faster laps with the 18's than the 19's, but the 19's were offered for aesthetics.

[1MOREMOD]

Originally Posted by pbonsalb

It is not like BMW's best handling package uses the smallest wheels. It uses the largest wheels.

The larger wheels are cosmetically appealing not necessarily performance upgrade. Would 21s increase handling? Why does every track junky run 18s?

[pbonsalb]

Probably because they are cheaper and there are more track tire sizes.

I read all the magazines and they periodically test different tires and wheels on the track. To the best of my recollection, the biggest ones typically are the fastest. Obviously, you can skew this generality with absurd choices like 40 lb wheels or 21 inch wheels and 15 profile tires, or stack the deck by running R compound 17 inch against street 18 inch.

[John ITRW]

Originally Posted by pbonsalb

Probably because they are cheaper and there are more track tire sizes.

I read all the magazines and they periodically test different tires and wheels on the track. To the best of my recollection, the biggest ones typically are the fastest. Obviously, you can skew this generality with absurd choices like 40 lb wheels or 21 inch wheels and 15 profile tires, or stack the deck by running R compound 17 inch against street 18 inch.

That is plain old wrong. Does any racecar run a big wheel. No. They all have a pretty meaty tire on a relatively "small" like 17 or 18 inch wheel

[1MOREMOD]

Originally Posted by Zebra M3

That is plain old wrong. Does any racecar run a big wheel. No. They all have a pretty meaty tire on a relatively "small" like 17 or 18 inch wheel

ding ding, we have a winner. someone is paying attention.

[slicer]

I think that there is a balancing point of performance between too large and too small (that's what she said). That balance-point differs depending on the car and the overall tire diameter specified by the manufacturer. For example, an e92 M3 is designed for a far taller tire than an e36 M3. If you put an 18" wheel on an e36 it is the equivalent (tire side-wall height wise) of putting a 20" wheel on an e92 M3. I personnally think that an 18" wheel on an e92 M3 is the best sizing for true track performance. The 18" wheel / tire nails the best balance of performance due to a good sidewall height (not too short not too tall) and great tire availability. The 17" wheel gives you a taller side wall height than is ideal IMO, plus you can't fit any big brakes and we all know that OEM brakes are one of the biggest weaknesses of the car. That being said, I have never tested a 17" wheel/tire on an e92 M3, I'm sure a lot of fun can be had with a 17" wheel and they are cheaper. If you never have any intention of upgrading the brakes and want to save money then go for it.

[Kunman]

Originally Posted by slicer

I think that there is a balancing point of performance between too large and too small (that's what she said). That balance-point differs depending on the car and the overall tire diameter specified by the manufacturer. For example, an e92 M3 is designed for a far taller tire than an e36 M3. If you put an 18" wheel on an e36 it is the equivalent (tire side-wall height wise) of putting a 20" wheel on an e92 M3. I personnally think that an 18" wheel on an e92 M3 is the best sizing for true track performance. The 18" wheel / tire nails the best balance of performance due to a good sidewall height (not too short not too tall) and great tire availability. The 17" wheel gives you a taller side wall height than is ideal IMO, plus you can't fit any big brakes and we all know that OEM brakes are one of the biggest weaknesses of the car. That being said, I have never tested a 17" wheel/tire on an e92 M3, I'm sure a lot of fun can be had with a 17" wheel and they are cheaper. If you never have any intention of upgrading the brakes and want to save money then go for it.

very good points, however according to apex, 355mm BBKs still fit on the 17inch rims, and the stopping power and heat dissipation between the 355kit and the 380kit is minimal.

[slicer]

Originally Posted by Kunman

very good points, however according to apex, 355mm BBKs still fit on the 17inch rims, and the stopping power and heat dissipation between the 355kit and the 380kit is minimal.

I assume you are referring to the 355mm Stoptech kit. Do you know if they fit the 365mm brembo kit? AP Racing kit? Alcon? I'm curious.

[Kunman]

Originally Posted by slicer

I assume you are referring to the 355mm Stoptech kit. Do you know if they fit the 365mm brembo kit? AP Racing kit? Alcon? I'm curious.

Taken from this thread: http://www.m3post.com/forums/showthread.php?t=795703

Originally Posted by Eddy@ApexRaceParts

The 17x10" and 17x10.5" wheels were designed to clear a Brembo and Stoptech 355mm BBK on the E9X M3 application, not to mention the stock brakes.

This makes it an ideal budget track wheel or even a winter wheel for people who need to clear a BBK when running a 17" wheel.

I am not sure if they fit the 365mm fit, maybe apex would know.