Socko

It feels close enough to identical I can't tell a difference, brake pedal is still over the gas pedal when braking heavy for easy blips.

ZedO6

If the math is right on the piston sizes vs stock, you shouldn't feel a difference in height or movement. Once hot, the pedal won't fade from caliper flex either

Socko

so i was sitting on my *** and its 75 outside so i decided to start measuring up the next step. All pics are of stock c5z speedline 17" and 18" wheels with a centric 13.4" c6z51 rotor and fsl6r wilwood calipers on my 03 c5z.

So on my new bracket design specifically for 13.4" rotors i added .25". As my current bracket was setup to run JUST under the chamfer on the 12.8" rotors i use, i figured this would give me more flexability as i can always add a shim between the bracket and the caliper to get a tiny bit more space if need be.

So first 2 pictures are of the spacer and my stud engaugement at that point. That is a .25" spacer and the 2.5" arp studs. The stud enguagement will be relativant when/if i go to 14" rotors on my new 13.4" brackets.

So after that some more interesting pictures for people most likely. The 3rd and 4th picture are of the the 17" wheel on a 13.4" rotor. It has between .05" and .06" clearance without a spacer, and as you can see plenty with a .125" spacer. 3rd pic is without, 4th is with a .125" spacer. This spacer still leaves plenty of threads imo on stock studs. I might go with the threaded to the end ones when i change the hubs, but it seems safe.

Last pic is of a 13.4" rotor under the 18" rear wheel. I didn't feel like going through 100 feeler guages but the clearance is over .1" it is closer to .115-.120" i believe, without a spacer so plenty fine imo.