sebdavid

Weird. For me, no spacers needed, no rubbing, with stock rotors or 2-piece DBA 5000s.

RedLS1GTO

The variances seem to be coming from the rotors themselves from what I can tell. What brand of "stock" rotors are you using? I have tried both NAPA as well as those that came from the factory on mine in '02... since I am apparently a hoarder, I had them laying in the garage and tossed them on it just to check.

Do you have any shims spacing the caliper bracket away from the knuckle in your setup? Does the rotor line up in the middle of the caliper or is it offset a little?

If you are curious (I am), the next time you have them off of the car try to get some measurements on them (hat offset, hat thickness, etc.) I have the J-hooks on the car now getting ready to go out this weekend. When I pull them off next week I am planning on measuring what I have and see if I can find where the delta is happening.

sebdavid

Various NAPA and cheap ones from less-identifiable origins. Can't really go much further than that. If memory serves, clearances are kind of tight but no rubbing (I think I would have noticed). I am not using stock-style rotors any more, sticking with 2-piece ones, so I can't give you more info. But with the number of kits sold, I think we would know by now if it really wasn't working with stock rotors. I have no idea where the variance between users could come from.

RedLS1GTO

I'm thinking this might be where we are seeing our differences. If you have tight clearances you could be off at least a tenth or 2 from where mine are. I have been shimming mine out to get the rotor dead center in the caliper (I'm **** like that). With the J-hooks, there with no shims to ge tthat same alignment. Pushing the caliper out also pushes it closer to the wheel itself which is the reason for the spacer.

Don't misunderstand my post. It absolutely 100% works with stock rotors. I use the car as a DD with them and carry them as spares.

... they just require a little adjustment to get everything aligned to the same place that the J-hooks are. They can be swapped in a matter of minutes once you know the number of shims and can just toss them in.

sebdavid

You state without shims the rotor would be rubbing on the caliper. That's what I was referring to. Unless nobody else is using the kit with stock rotors, wouldn't we and Hardbar know about it by now if that was the case for most people? This is perplexing, again, I don't know where the variation coud be coming from.

RedLS1GTO

When I say rubbing... I am talking about a margin of thousandths.. or even ten-thousandths. It BARELY rubs the inner side caliper. It is a small enough margin that it would be well within the tolerance loop of the machining process for the knuckle face, 2 bracket faces, and the caliper mounts.

sebdavid

Ah, well that I may not have noticed, and it may have "rubbed itself free" without me noticing since I wasn't the one who installed the kit in the first place and I had a long highway drive back from the shop after it was.

RedLS1GTO

Yes, it is indeed such a light rub that if you hopped in the car you might not have noticed it.

On that note, I would be interested to hear where JeremyGSU's issue is that he "could not get them to fit under the caliper".

I just looked it up and best I can find GM uses a .003" tolerance on rotor thickness. WAY more than I thought. I would be willing to bet that NAPA and the other Chinese rotors aren't any less than that. When you combine that with what is most likely a .002" tolerance on hat thickness, .001" on rotor offset as well as bracket offset, .001-.002" on the knuckle, .001" on the caliper itself, and most likely .002" on the hub assy. you could have variances of as much as .012" from set to set with all parts being perfectly within acceptable tolerances . Mine most definitely falls within that variance.

EDIT: Forgot to account for the knuckle face (where the hub sits).

Tolerance loops are a bitch.

*Disclaimer - I am using educated guesses on those tolerances. They could very easily be more or less than my numbers but the point remains that when you start adding them up you can see some pretty noticible differences from 1 to the next, even with all "good" parts. Such is the life of a nerdy engineer.

RedLS1GTO

I finally got the chance this weekend to drive these things in anger. Well, at least HPDE anger. All I have to say is wow. Just... wow.

The only issue I ran into was with it being so cold (low 50s) that I couldn't get enough heat in them with the Ferodo 1.11 pads, especially when I was mixed up with some of the slower traffic. I have the LG spindle ducts and they were working TOO well. I taped off about 2/3 of the opening and they came up to temp like a dream.

What an awesome AWESOME setup.

StreetSpeed

Ordering this kit as soon as it is back in stock from Essex. Destroyed my brakes after the second session at NJMP this morning. Headed home tomorrow morning with zero pedal and a very nasty "clunk" from the Centric rotors. I was gonna swap everything out at the track but I just figured with a car this fast it's time to spend the money to make sure your brakes work every time you hit the pedal.

Essex do you know when the kit will be back in stock for the C5?

Caveboy

I got the AP racing front brakes. What is everybody running for street pads and for the back brake system?

el es tu

The general consensus is run the same compound in the rear as youre using up front or one thats less aggressive than what youre using up front.

Adam@Amp'dAutosport.com

Take a look at the Carbotech 1521 pad for street use. If interested let me know and I will be happy to set you up.

Carbotech™ Bobcat 1521™ The Carbotech Bobcat 1521™ is our high performance street compound that is our most successful compound. The Bobcat compound is known for its awesome release and modulation, along with unmatched rotor friendliness. Like our AX™ & XP™ line of compounds, Bobcat 1521™ is a Ceramic based friction material offering minimal rotor damage and non-corrosive dust. Bobcat 1521™ offers outstanding performance, even when cold, low dusting and low noise with an excellent initial bite. This compound’s virtually perfect linear torque production provides incredible braking force without ABS intervention. Bobcat 1521™ operating range starts out at ambient and goes up to 900°F. Bobcat 1521™ is suitable for ALL street cars, perfect for your tow vehicle, police cruiser. The Bobcat 1521™ compound has been found to last two-three times longer than OE pads you can purchase at a dealership or national retailer. That’s one of the beauties of Carbotech Ceramic brake compounds. Bobcat 1521™ is NOT recommended for any track use.

Caveboy

what type of rear brake system is a good compliment for these front brakes?

el es tu

http://www.essexparts.com/shop/compl...te-bundle.html

JRitt@essex

Thanks for posting that!

The BBK in the link above uses the same pad and iron disc ring as the front Hardbar T1 Kit and our Sprint Kit. That means you can swap pads or iron front to rear, and you don't need to keep many spares on hand.

JeremyGSU

Did they notice an improvement in braking adding the rear system over the stock C5 rear calipers?

JRitt@essex

Below is some feedback from one of my customers...has a ridiculous number of miles on his car with and without our brakes.

“When we put the front kit on last year I was very pleased with how much of an improvement it made in pedal feel and effort….not to mention the longevity of the parts. But now, after upgrading the rears too, I am convinced the complete kit front & back is the way to go. The stock rears inject a sloppiness into the system that no amount of upgrades on the front can illuminate. Pedal is rock hard now and pedal travel is less. It took some adjustment of my heel toeing to compensate but the pedal is MUCH more consistent now. The front upgrade was a good improvement but to get the greatest benefits you definitely need to do all 4 corners. ”

Regards, Pat Smith
Chief Instructor, Carolina Motorsports Park

GettReal

Hey Jeff, 2 questions.

1) Do you have the hats available for the Jhook rotors? I have a couple new discs on standby but Id like to mount them on new hats so its a complete set. Doesn't look like I can get them from Hardbar anymore.

2) do you have a rotor/hat (preferably jhooks) for the rear that will fit with the rear OEM Calipers?

Steve

JRitt@essex

Our hats are unfortunately not the same offset as the Hardbar hats. You therefore can't run our hats with the hardbar caliper bracket.

No, we don't offer a direct replacement disc for the rear. Sorry!