MB Dave

Another example.

Take the Cadillac CTS V Sport (not the cts - v) The summer performance tire is standard on the 18. Upgrade to the 19 you get all seasons. The reasoning behind is that smaller wheel are more performance oriented and you have more tire options down the line.

kuba.95

The CTS-V is sportier and more track oriented then the CTS V Sport, and the standard tires on it are 19".

Tjdehya

Did you do your homework?

Give me a good example where the track version of a car had smaller wheels than the street version.

Good Luck!

TTA850

Gallardo LP560-4 had 19" wheels, Gallardo LP570-4 Super Trofeo had 18" wheels

That trend continues with the Huracan

Huracan LP610-4 has 20" wheels, Huracan LP620-2 Super Trofeo has 18" wheels.

http://www.lamborghini.com/en/master...pecifications/

http://squadracorse.lamborghini.com/...pecifications/

http://www.lamborghini.com/en/models...pecifications/

http://squadracorse.lamborghini.com/...pecifications/

TTA850

Also Ferrari uses 20" wheels on the 458 Italia and 458 Speciale but 19" wheels on the 458 Challenge

http://corseclienti.ferrari.com/2014...ari-challenge/

Tjdehya

OMG really? There are two of you?
I thought this stuff was general knowledge.
OK.. school time! lmao

http://www.jags.org/TechInfo/2001/05...redescript.htm

This stuff is basic cars101. There comes a point where the disadvantages that larger wheels bring outweigh the advantages. I am pretty sure that every performance/racing division knows what size that is for that particular vehicle.

If 18s gave the best performance for the C63, AMG would not put 19s on it if they degraded the overall performance of their "higher performance" vehicle. End of discussion.

TTA850

Let's get one thing straight, your both wrong. Here's some schooling for you - there is NO hard and fast rule to what size wheel and tire works best for road racing or drag racing (both of which btw are performed on a Race Track ) - the correct answer for which wheel and tire combination is best comes down to so many individual differences within the car, suspension design, chassis design, race track design, driving style, weight, power, transmission type, weight distribution, and so on. For those reason I have several sets of wheels and tires of varying size, tread design, and compound for my race cars and that's just to adapt to different tracks and changing track/weather conditions. Also your basic cars101 is referring to aspect ratio which has nothing to do with the wheel diameter that your claiming bigger is better. The only time wheel size would come into play is when your trying to reduce aspect ratio while maintaining overall tire diameter.

So I'm in no way saying 18" wheels perform better than 19" wheels as MB Dave stated, I'm also not saying 19" wheels will outperform 18" wheels as you stated. With so many variables you would be wrong to make either statement. The fact that the S model comes with larger brakes may have been reason enough for AMG to have to use 19" wheels for caliper clearance rather than ultimate performance.

You did however ask a question…

To which I gave three good examples

MB Dave

Once again accept that your wrong and amg is a blend of form and function, let me guess you also believe that titanium 19" wheels are made out of titanium as well lmfao...

What you posted has nothing to do with wheels, aspect ratio is the tire height much different from wheel height but I see how that might be too much for you to handle as you think that bigger wheels are better for track purposes.

But since were in the habit of posting links here you go.

http://www.caranddriver.com/features...d-tires-tested

http://tires.about.com/od/understand...nus-Sizing.htm

Will617

Lots of opinions with some good research.

Personally I want the 19" wheels because I think it looks better. Not too much worried about which one handles better. Unless you are a pro I don't think it will make a lot of difference if you are a weekend weekend warrior on the local race track.