wheel size/performance
 

the ss is suposed to come with 20"s? dont you folks think that is too big for a performance based car? when i think of 20" wheels the first thing that comes to mind is a blinged out 300c rolling down the highway

All performance cars come with larger wheels for large brake clearance. The Viper has 18/19s, the Corvettes I think have 19/20s and all the European performance come with larger wheels also.

I guess I don't see there being much of a problem here. The overall tire diameter is roughly the same regardless of whether you are running 18", 19", or 20" wheel options.

18": 245/55R18 = 28.61"
19": 245/50R19 = 28.65"
20": 275/40R20 = 28.66"

The difference in tire sidewall height is 1" between the 18" and the 20". Depending on the particular tires used, that 1" could make performance driving the same or scary. Too soft a sidewall and the ride is more comfortable but performance cornering is questionable. With a stiff enough sidewall, I don't think many people would be able to tell the difference.

Comparing unsprung weight, given that the overall size is the same, you are gaining tire weight and wheel weight by going up in wheel diameter. Since specs for the Camaro wheel/tire combos aren't yet available, here's an example for the Z06 (only found this information on one website so validity is questionable):

OEM 18" front wheel: 22 lbs ea.
OEM 19" rear wheel: 26 lbs ea.
OEM Goodyear F1 Supercar extended mobility front tire 275/35ZR18: 29 lbs ea. (new)
OEM Goodyear F1 Supercar extended mobility rear tire 325/30ZR19: 36 lbs ea. (new)

18" total weight: 51 lbs. each
19" total weight: 62 lbs. each

Granted the Z06 example probably isn't the best comparison because by moving up to the wider tire, you are also gaining an additional 1.1" in tire diameter and weight (25.57" for 18", 26.67" for 19").

Your best bet is a trade-off between reducing unsprung weight, increasing tire sidewall stability, and comfort in everyday driving. It will be different for everyone.

But it mostly comes down to asthetics. Which do you like better - more wheel or more tire? :)

I'll tell you at first I was against the 20s, but after thinking about the pizzas they're stuff inside for brakes, I don't oppose it now. When I learned about the 28"+ tall tires, I was a little concerned. I think I'll lower the aspect ratio on the first replacement set if tires I go through. Lower height equals a little better acceleration (how much, I don't really know) and I'll give up some comfort due to the shorter sidewall, but won't really care.

I wonder what is the largest size I can run on the rears though. The biggest I could run on my '02 was a 335-35-17 and am hoping I can get into the 3XXs with this car. Fat rear tires are cool IMHO :)

Less unsprung weight is almost always a good thing.

The only way I can think of to have both a lighter weight wheel and a 20" diameter is to go with a set of aftermarket Magnesium/Ultralight wheels...