Deputy_Dangle

I just installed a set of C6 Z06 brakes on my C5 with 18x10.5 Alcoas all the way around. The clearance between the caliper and spoke of the wheels is pretty tight. I tried my best to measure the gap with a set of feller gauges and came up with about 1.8mm (.070'') clearance at the tightest spot.
I did a decent amount of research to the subject but found varying answers from some of the large brake companies. One company stated 1.5mm was acceptable and others said 2mm or 3mm was the minimum requirement. I've even had a few Auto-X guys state they have ran with clearance of 1mm (.040'') and not have any issues.
I understand there can be an amount of flex, be it the actual wheel or the wheel bearing under hard use. I use the as a hard driven curvy back road street car 99% of the time and I hit up the occasional Auto-X.
I guess my question is, does any one have experience with this same set up or something similar that could give some real world feedback?

Thanks in advance
Clay

63Corvette

My STREET wheels (18" Z06 replicas) have about the thickness of a matchbook clearance between the caliper and the wheel spokes. I do tack the car occasionally on those wheels and have never had a problem. (Your results may differ). I also run 18" Kinesis K28 wheels with slicks, but the spokes have considerable clearance (0.75") to the spokes.

Socko

i believe that the stuff i have seen says .08-.09 but it seems the drum clearance is more relivant. Obviously the tire in applying the load and if .09 is ok for drum clearance the spoke clearance is less. Then again could just get a .125 spacer and not worry.

At the end of the day in .09 is enough for track then its enough at 1.4ish g's and slicks. Which means it is likely fine to have .07 with a street tire of drum to caliper clearance which is less at the spokes. Assuming your wheel bearings work, I have no idea what play can be with a bad bearing. At that point you have bigger issues then a scratched rim or caliper.

Bill Dearborn

When I had my C5Z I was using the LG G Stop kit with the wide Wilwood SL6 caliper. It cleared the front wheel spokes easily but when I put 18x10.5 rear wheels all the way around the spoke cleared the caliper by about 1/16 of an inch. To avoid any damage to the wheels or the caliper when on track or at an autocross I started using a 1/8 spacer when I had the 18x10.5s in the front. To make sure the lug nuts had enough threads to engage on the wheel studs I changed them over to stock length Dorman studs that are threaded all the way to the end. That way I had plenty of threads engaged in the lug nut and when I was running the stock front wheels on the street my wheel studs were short enough to fit under stock lug nuts.

Bill

Deputy_Dangle

Thanks for the input guys. The only reason I am trying to avoid a spacer is because I havn't recieved my new tires in to mount on the 18x10.5's in the front and I am worried it will cause the wheel to poke out past the fender. Maybe once the tires come in I acn get everything mocked up and see if I have enough space to run the spacer. I have extended ARP studs so the only thing holding me back is cosmetics.

But with that being said, With good wheel bearings, and street tires (NT05's), I really can't fathom having enough grip to make the wheel flex almost 2mm. I'd hate to be wrong though.

SouthernSon

Yep, I had the same problem and run the same spacers. In a tight turn you can hear the calipers clicking on the 18's up front like playing cards in the spokes of a bike.

Except I use the ARP longer studs.

froggy47

Do you use the c6z brackets also? Is it just a bolt on? Can you put the c5z fronts on the rear?? Hope this is not too off topic. I am thinking of exactly this upgrade.

Deputy_Dangle

Yes, It is a direct bolt on as long as you use C6 Z06 rotors, C5 SS brake lines and have a wheel that will clear. The C6 Z06 caliper is a fixed lug mount so no other bracket is required.

I have heard of people putting C5 front calipers in the rear but I don't know how it would effect brake bias. Also, I would assume it requires you to run a C5 front rotor in the rear which would cause you to loose your e-brake.

SouthernSon

With more fluid volume in rear caliper upgrade you will experience longer brake pedal travel; will mess up your blip and brake position of pedals. You might consider a different master cylinder to correct the problem.

froggy47

Maybe I should leave the rear alone.

froggy47

Sounds good, how do the c5z rear compare to c6z rear calipers

I am not getting anywhere so far with the ctsv calipers on c5z.

Bill Dearborn

C6Z rear calipers have 4 pistons and use a 13.4 in rotor. If you aren't going to be doing any heavy tracking of the car and can get a good set of front/rear calipers/rotors in the $800 range they may provide some benefit. However, if you plan on working the brakes hard at a bunch of track days your best bet is to spend the $800 on a full set of Wilwood front and rear BBKs. TCE and others sell them at some fairly reasonable prices. You can even get a front set that permits use of the C6Z front rotor for not much more than $800.

Bill

froggy47

Do you have the model #, my head is starting to hurt with all these kits.

I really want to stay with (cheap) blank rotors, for mostly autox (not many laps) the "economies" of 2 piece rotors isn't there.

briannutter1

I run 18x10.5 rears on the front with my Baer 6s 14" calipers. I had to grind down the caliper just a tiny bit to produce .080 clearance and its never touched.

XXXLTRP

It will be real close to flush with the fender. I just moved my rears to the front with 295/35/18 NT05 and any spacer would def push them past the fender. One side is perfectly flush and the other side sits a hair outside.