Den, I'd get dimeensions for the GN hubs before I would buy them, pay particular attention to the wheel register diameter versus the diameter of the hub in that area, I have to lathe down the drive plates and the covers on the floater rear, to fit inside the wheels I was using. Also, make sure you get 1/2" studs installed, Coleman will do the custom drilling for a reasonable fee, they are super good to work with. If I recall, even their Impala hubs were too fat to fit inside a normal wheel, but I might be mistaken. It feels to me that the path of least resistance is to cut a stock impy/full size car hub like you had suggested before, lathe it down so a replacement type rotor will fit over it.

A super rigid spindle would be nice for my car right now, I still have horrible pad knockback, and it was not too confidence inspiring at Willow Spring's last weekend, that track is FAST.

Mark

I remember seeing on one of the aftermarket brake websites recently, "anti-knockback springs" or something like that - perhaps springs that go under the caliper pistons to keep them extended?

Aha, this isn't where I found it, but it describes them:

http://www.stoptech.com/tech_info/glossary.shtml

"Knockback springs : Small coil springs fitted inside the caliper pistons of some brakes to prevent the pads from excessive knock back from flexing of the suspension system or run out in the discs. If the disc run out is within specification and the upright/axle assembly is sufficiently rigid, there should be no need for knockback springs. However, when operating conditions are severe with regard to either generated side force or bumps, they may be required on the best of designs. "

I have spoken in depth with Rory over at Coleman, I am going with Impala aluminum hubs drilled with a 5X4.75 pattern. The hub snout is 3" and the rotor drive plate is part of the backside of the hub. The studs are still 5/8" but McMaster has a solution to that...1/2X20 threaded coil inserts with stake in place drive pins.

They told me they dual dill the aluminum hubs now with both 5x5 and 5x4.75 wheel stud patterns. For an extra $25 per hub, they'll drill the second set of holes for 1/2" studs instead of 5/8".

Yes, they are drilled for 5X4.75, I hadn't discussed only drilling for 1/2" studs however. $50 for the pair with 1/2" studs or 15 bucks for McMaster inserts, both just as strong. In fact, I think the steel inserts would actually hold up better long term than tapped aluminum holes (assuming you run threaded studs as I do vs. press-in versions). Keith, you must be the guy he keeps insisting is me. Every time I talk to him he says "didn't we just talk about this".

Ya, I've talked to him a few times. :)

Rory and team are incredible. If you haven't used Coleman before, I can't say enough about their service.

PT: I have read and heard about the anti-knockback springs too. I should research this further, but it is clear to me that the issue is the flexure, and I really want to solve the issue rather than masking it with a bandaid. If it flexes, it probably isn't good, 'cause at some time it could yield, and I'd have to think that something like that wouldn't be good. :_paranoid

Ahhh, the joys of hot-rodding. Fix one issue (in my case, front brake capacity, I switched from the flaoting PBR twin piston, 13 x 1.1" rotor deal to a full Alcon six pot, fixed caliper, and big ole 13 x 1.25" rotors, and I still don't trust my brakes!!), and create another. We're a sick bunch I tell you.
M

I'll second that. I didn't put "addict" in my handle for no reason :)

What type of wheel backspacing would need to be run with this new spindle set up for a 9.5" rim in front?

I'll let you know as sson as I get them assembled. Backspacing won't be as critical as diameter will. 17" will be a must.