Difference Between early and late rear knuckle
Thread Starter
Instructor
Joined: Dec 2020
Posts: 111
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Difference Between early and late rear knuckle
In my quest to make the lightest c4 ever I am trying to drop every gram where I can. One thing I wanted to get rid of was the rear wheel adapters. I was running c6 offset wheels on an 85 and I was using 1 inch adapters. The adapters weigh around 3lbs each with nuts. So I decided I would try a set of late model c4 rear knuckles. They came in today and I started to install. first impressions. After removing the abs wheel and sensor the knuckles weigh the same 24lbs. They appear to be approx 1/2 to 3/4 wider on each side measuring on the floor. The calipers are will bolt up but the rotors are completely different. I am about to order a set of 2 piece late model rotors from Baer. Also the lower shock mount is different. I am running coilovers and I am trying to figure out a solution. I just wanted to share what I have. If anyone needs any measurements or comparison pictures before I complete the install let me know.
Tech Contributor
Joined: Jun 2004
Posts: 20,910
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From: I tend to be leery of any guy who doesn't own a chainsaw or a handgun.
I've spent similar time looking at the early and late rear knuckles. I'm using early knuckles under my '69 to help reduce the trackwidth so I can use C3 wheels for a stock look. One my street rod I currently have the later rear suspension, but I'm playing with mixing in the early caliper mounts and stub axles to tuck the wheels in a touch. So far it looks like I can mill an eighth inch off the stock late rotors radius to match the early rotor radius, and then shim the early caliper mount ears to work with that later rotor.
