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On my setup I am using 88-96 corvette C4-HD (13 inch) brakes which requires a larger offset hub (the heavy duty, HD, hub). The C4 HD 13-inch front rotors have a large offset (rotor inside hat to rotor rear surface), in order to fit the caliper bracket and caliper in between the spindle and the rotor you need a large offset hub to push the rotor out further. To achieve this larger offset you will need to create a hub with a larger offset by starting with a rotor that has a larger offset like the 88-92 F-body 1LE rotor. I have done this below, another option is to turn down a stock rotor and use spacers. I do not recommend the spacer method as it will put more load on the front bearing. One benefit of the HD hub over the standard hub is the front wheel bearing is larger then the standard thirdgen rotor.
Brake upgrades using 88-96 corvette C4 Non-HD 12-inch (with C4 rear rotor), LS1 F-body, and corvette C5 & C6 setups you can machine down the factory 82-92 F-body rotor into a hub in the same process seen below.
You can take a set of rotors to just about any local machine shop and they can do it for you, all they need is a lathe. Make sure to bring the new rotor with you so they can check fitment.
1) Since it is very hard to find someone with a used set of 1LE rotors I started with a brand new set.
2) Spray on a penetrating oil (eg. PB Blaster) on the studs and let it sit for 15 min or so. Use a press to remove the studs or tap them out with a hammer.
3) Now you need to cut the rotor off the hub to prepare it for machining on a lathe. I used a angle grinder, which is a simple but effective way of doing it.
4) The hubs need to be machined on a lathe to take off the extra material so they will fit inside the hat of the rotor. Also this step is needed to make them round and balanced. For C4 and C4 HD upgraded take the hub down to a 5.95 inches diameter. For other setups just bring the new rotor you are going to use into the machine shop with you and tell them to machine it down until it fits into the hat of the rotor.
For LS1 rotors and some C5 & C6 rotors there is an inner lip cast into the inside of the rotor hat. The hubs need a taper cut into them to clearance the this lip in the rotor. If you do not account for this the inside of the rotor hat will not sit flush against the hub. This is easy to do while the hubs are on the lathe. Below is a picture of a standard Thirdgen rotor turned into a hub to clearance a 12″ LS1 rotor, note the lip \ tapper on the front face of the hub. The LS1 hub is turned down to a diameter of 5.87 inches, C5 and C6 setups should be similar but may be able to accommodate a larger diameter hub.
5) Here is a final picture of the HD hubs after they have been prepped with a coat of por-15 and are ready to go on the car.
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Page created: January 2006
Page content last updated: October 2011
how much did it cost to have the hubs turned down?
thanx
It’s been a few years since I had them done but I think they were about $50. You should be able to have them done for under $100.
I have a question for you luke. i have a 83 Z/28 with a disc brake rear end. I wanted to know if you knew what woud be needed to install CTS-V rear calipers on my car and fronts??
why didn’t you just use a set of light duty 80’s B body rotors instead of wasting a set of expensive 1LE rotors? the light duty 80’s Caprice has the 5X4.75 bolt pattern and uses the same wheel bearings as the 1LE. it’s only an 11″ rotor, but that doesn’t matter since you only need the middle part for the hub. those cars are all over in the junkyards and a pair of used rotors can be picked up dirt cheap.
Nice suggestion, just looked the rotor up it has a larger offset then the 1LE router. 1LE rotor height: 4.32″ 83 Caprice 11″ rotor height: 4.65″
The rotor offset shouldn’t make a difference, only the bearing to the hub surface. I can’t seem to find exact dimensions but from pictures it appears that the hub surface to the rotor is the change.
Hey Luke awesome site man, just curious what length wheel studs are needed for the ls1 conversion?
Thanks man
The stock wheel studs are M12-1.5, Knurl Diameter: 12.73mm, Length: 41.5mm 1.63″, add the thinkness of the rotor hat mounting surface to the length and use studs closest to the new length
Thanks for Lots of great info.
For studs, I used DORMAN 610323 . I got em pretty cheap from Rockauto that way. They’re 54mm long compared to the factory 41.5mm long, so it actually works out nearly perfectly.
Hi, I know I am a little late for this question,
But I have a 90 Iroc z done the rear swap brakes from another Iroc with the 10 bolt rear disc brakes, now wanting to do the upgrade like stated above, my only issue is, I so want to use my stock 88-90 Iroc 16inch wheels and tires, can I use them with all these modes? Or is there another way to add upgraded brakes? Would like a 3-4 piston swap, don’t have to be 6 piston,
I also found a needed junk yard with Vetts from all years, cts Cadillacs from 05-12 models v6 brake set ups, plus many more out there, would love to stop at least 110 ft from 60 to 0 or lesser if posable, front and rear wanted,
Thanks so much. And great site u have with good info for all of us 3rd gens
(Helping bring them back to life again)
So I want to be sure I understand,I have 91 z/28,want to install c4 standard(12″) rotors and calipers,have my standard 10″ rotors turned down to fit in standard 12″ front rotors,and have spindle bracket made?only doing front brakes.
I’m confused where you said to use spacers with stock rotors. If I turn down a stock rotor to fit ls1 brakes. Where would the spacer go?
Between the hub and the rotor
howdy Luke, I found your site a while ago, thanks for going to so much effort to help out all us car junkies. I am building a 54 chev truck, TCI IFS, with 86 gen 3 brakes, which I have now converted with 68 Camaro front drum hubs, 2010 camaro Brembos, Holden HSV 365mm front rotors, custom adaptor bracket to fit the M2 drop spindle. Wrapped in 20″ American racing rims. If you would like pics, bracket drawing and words to add a page on it, I am happy to send you stuff. Coop, Australia.
Hey Luke, been trying to figure out this 2010 brembo brake set up in my 68 camaro. I been trying to check different web site and nothing specifies what hub to use :/ do I cut out the disc part out of the stock hub? Can you help with my options? If you have info when i get to do the back pointers will be appreciated.
Thanks
NELSON
[email protected]
Hi Im also confused.89 transam gta. stock hub for ls1 setup, when i put the rotor on the hub and install the stock wheel, will the wheel move outwards from stock more? it will not sit as factory because there is the ls1 rotor on the hub!
am i correct?
Hi, I’m Ted. What is the smallest wheel diameter that will fit over 1989 Camaro/Firebird 1LE Rear Performance Brake option calipers, please?…Thanks.
Hi, I’m Ted. What is the smallest wheel diameter that will fit over 1989 Camaro/Firebird 1LE Rear Performance Brake option calipers, please? I’m thinking 16″ but I’m hoping 15″ for more tire options….Thanks.
Hi, Ted again. I’m thinking 16″ but I’m hoping 15″ for more tire options….Thanks.
I am using the 1LE hub and the C4 13 HD front rotor on my 1992 Camaro and using 2014 Camaro brembo calipers which brackets will I use and what spindle mods will I need to make
I’m during 1le hub and c4 13 rotor and 2014 camaro brembo calipers on my 1992 camaro what bracket will I need and what spindle mods will I need to make and will the 1le hubs work on my stock camaro spindles or will I have to find the rare 1le spindles
I’m during 1le hub and c4 13 rotor and 2014 camaro brembo calipers on my 1992 camaro what bracket will I need and what spindle mods will I need to make and will the 1le hubs work on my stock camaro spindles or will I have to find the rare 1le spindles
Hi,
I race a 2nd and a 3rd Gen Camaro and years ago a mate of mine did your conversion above on his 2nd Gen race car and it lasted about 2 races until it catastrophically failed and he was lucky not to wreck his car. Because he wanted to continue using the rotors and bells he had he commissioned a batch of hubs machined from a steel billet at great cost. He managed to sell a couple of sets and recently I bought a set he had lying around for years and I am now thinking of using on the 3rd gen and your info on the corvette discs is useful however I would warn people the dangers of machining down a cast steel rotor like you have and its likelihood to fail.
Not sure how that happened! I’ve raced my third gen Camaro in American Iron NASA road racing for 4 seasons with a set of stock rotor/hubs turned into hubs with absolutely no issues on Toyo RR race rubber. Also, I have unfortunately hit the wall several times (long story) and literally blown apart wheels and rotors, bent spindles, bent struts, broken tie rods (alum pieces) and never did the hub have any issue whatsoever.
The car actually had Coleman racing aluminum hubs when I got it, and they would always loosen up. Finally figured out what was happening – all that brake heat (C6 14″ rotors) was heating the aluminum hubs up, and since aluminum expands so much quicker than steel (thermal coefficient of expansion), the .002″ press fit was disappearing when at elevated temps, and the bearing race would spin inside the aluminum hub. That caused the actual hub to wear and was the reason the overall wheel bearings would loose up. Took a bit to figure that out.
Luke,
Just wanted to confirm on the hubs, I’m looking at a LS1/CTS-V1 conversion. Can I machine my stock 82-92 hubs or do I need a set of 1LE hubs for correct offset?
Thanks,
Adam
Sto rotors ck ones need spacers – 1LE rotors may not depending on the wheels you are using :)
I have Sts-v calipers. How do they compare with Cts-v calipers
Luke, I have already turned down a set of gm metric G body rotors. I’m planning to put them on mustang 2 spindles on my 32 ford coup witch is just a bearing swap. are they made of the same steel as the 1le parts you talk about? I am concerned with strength.
Thanks
Jason
Hi Luke. Amazing technical information. I own a 89 iroc that I bought new in 89. Have done a few upgrades, suspension, rv cam,headers etc. it has collector plates. After reading your article I want to upgrade front and rear brakes. As these are stock 16” wheels , what would be the best combination for my car. 90% daily driver 10% auto cross.
Thanks
Colin
Hi Luke, only just came across this site today. I race a 69 Camaro in Historic Touring Cars in Australia. We run dics brakes on the front with a removable hat the is bolted to the rotor. Just looking at the hub that is fitted to my car it is completely different to a 69 Camaro hub. ie: it is a lot thicker and it has reinforcing ribs on the back side of the hub. (Much like the 1LE rotors you show in your explanation above. Right down to the thickness of the hub minus the rotor.)
To the question. Do you know if the 1LE hub rotor combo has the the same bearing spacing (front to rear as the Camaro spindle?). If not, can you advise what I could use to machine down that would be fit for purpose? Having an American car in Australia doesn’t lend itself to have a lot of availability to access and or cross match parts.
Hoping you can help.
Cheers Steve
Can you provide a part number for the wheel studs you used. I want to use 2” or 2.5” wheel studs but I’m not seeming to find the right fitment.