Just bought a set of C5 wheels. 17s in front and 18s in back. Will the 18s in back hurt my times significantly if any because of extra weight over the stock 16s?

Theyre 18*9.5 BTW. I'll be running a 295/35/18 tire.

 

Well it depends on what you consider "signifigant".

I would think you would lose .1-.3 seconds in the quarter because of the heavier rim and less sidewall flex.

Is the 18" tire a street or drag tire?

My suggestion, use a set of 16" stockers with some nitto drag radials for track use.

 

a little but not anything worth worrying about unless you are a serious drag racer.

 

Im about to buy a set of 17x8.5 Y2K C5 rims myself, let my know if they hurt performance bad, I JUST made a similiar post here to yours askign pretty much the same thing. People here are telling me to just but nittos on my stock rims. But i dont know. If i lose more then two tenths ill be pissed.

How much more would a chrome C5 rim weigh over a stock Z28 rim?