555ss

NO My GF has totally bent the hell out of the mounting ears the steel frame of the caliper mount was rubbing on the rotor... it was not long before they would give out. She only tracks the car 6-8 times a year 40 k mile car stock brakes with aftermarket pads.... it took her 3 more track days to kill them than me we have had NO issues with the new uprights. 5-6 track days. Gm Calls them a knuckle and they are cheaper than the stock C5 knuckle.

Olitho

Something does not sound right here. I have seen multitudes of very fast drivers, even multiple national T1 champs, run on the original spindles/knuckles without bending the ears. Caliper spread and other issues are common, but with OEM brake calipers and aftermarket pads, even on sticky A6 tires I have never heard a driver tell me they bent the ears on the spindle.

RX-Ben

I agree. I would think that the OEM caliper would spread before the mounting ears would be affected, and given the direction of the forces involved I'm not sure what would cause the ears to bend to the left or right.

jimtway

True, but a lot of us replaced said calipers many times without replacing spindles.

I have fought pad taper since I got my car. Recently at the track, my pads were sticking. I couldn't rotate the rotor without significant force. Hub bearing still good. I replaced the pins, rotors, pads and calipers. No joy. I have a new set of ZR1 spindles waiting to go on. Hopefully that will do the trick.

Olitho

Yes, and after a blown engine and ensuing big fire at a recent Majors race you also use hydroformed geology to help you suddenly stop your car. Who knows what happened to the spindles at that time.

555ss

Yes, the cars have had more than 2 calipers each on each side,( spread) yes we are on 315 A6's square, yes we crack 2 or more rotors a weekend. The cars both weigh over 3350 lbs w/ no areo.
We have both run the Glen sub 2:09 and the track we run the most is very hard on brakes NHMS.
All I can say is I have 4 stock knuckles that have bent mounting ears. up to .080" off measured from inside to outside.
Nothing is assembled wrong we have brake ducts but they do get incredibly hot.

The way I found the first bent set was, on my car when my new AP brake calipers would not fit over the rotor the ears were bent towards the rotor, we also run the SKF race bearings so it is not a radial bearing play issue.....

Razodo

For those that have installed the ZR1 knuckles, do they come with the upper ball joints included?

I need to replace my upper ball joints, for the price I might upgrade the knuckles if they come with the ball joints.

Pumba

The following picture shows the C6 knuckles, with the upper ball joint, as purchased.


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NemesisC5

Are part numbers referenced below the part numbers you purchased with the upper ball joint included?
Just wanting to make sure I have my numbers correct. Thanks Jim

Also, sent you a PM on another topic.

Originally Posted by RX-Ben View Post
Part number is 88965637 and 88965638.
$160ish per new.

Pumba

Scotty,

Yes, the part numbers listed include the upper ball joints.

JR

NemesisC5

Thank You Jim

Soloontario

Wow, good deal with ball joint included. BTW, the upper ball joint for the C6 is the same as the C5Z right?

Fulton 1

If running fixed calipers front and rear would it make sense to use these knuckles front and rear as well? Anyone know if these are direct replacement for C5 rear or is modification needed?

bsalie99

Do the ZR1 spindles for the rear too? or just the front

555ss

the zr1 spindle will fit in the rear but I have never heard of one failing or bending on the rear..
it is a direct replacement but the toe will be out, but with the spindle change it needs an alignment any way...