emptnest

I run advanced class HPDE in a 1999 FRC. I'm not the fastest guy on the track, and don't like to spend exponentially higher costs to shave 1 more second off my lap time. But I have enough skill to navigate the track safely in my class and to enjoy myself.

I previously ran a C4, so I have a good supply of 17 inch wheels, which I currently run on the C5. I am currently considering a brake upgrade, and I realize that most BBK's require 18 inch (or bigger) wheels. But, it looks like the AP Racing Sprint package would allow me to continue to use my 17's.

I know that going to 18's all around would provide a greater selection of tires, but I'm quite happy with my 315-35-17 Nitto 01's, and they are less expensive in 17 than 18 (for equal widths).

I assume that for any given RPM, I'm leaving a few MPH on the table due to the smaller tire OD. But am I missing other benefits, or suffering some unknown risk, by not upgrading to 18's?

clubracer23

Mark@AMT Motorsport

The AP Sprint kit (which is excellent) will clear the 17" rims, though you may need to run a spacer to move them out or the spokes may hit the calipers. At least I have to when running my 18" Speedlines (rear C5Z rims) at all four corners for my rain tires.

bb69

The AP calipers only clear the stock Z06 rims without a spacer. I would stay with 17s if you're happy with your tire availability. They offer less rotational inertia. The main reason race teams move to larger tires is for endurance reasons. A larger tire takes longer to get hot, so it lasts longer/is more consistent during a race.

Ken

Bill Dearborn

The 17 inch combo you are running used to be the hot setup for the C5. If you are happy with the Nitto 01s I would stick with it. When I switched from the 17x11 wheels at all 4 corners (with 315/35 Kumho V700s mounted) I tried 4 C5Z 18x10.5 wheels and never found a combination that was as great as the 17x11s. That was one of the things that convinced me to move from my C5Z to the C6Z a few months later.

Bill

maj75

emptnest