Calling all C5/C6 Guru's!!! 2nd Gen F-body Conversion Question?

[ryeguy2006a]

I have a 1976 Trans Am, and just bought some 19" BMW rims so that I can do the C5 front brake conversion. I was wondering if the 3rd gen fbody hubs will allow for more wheel offset? The front rims are about 5 inches of backspacing with the tires, and I need about a 1/2 inch spacer to make it fit correctly. Would the 3rd gen wheel hubs give any additional wheel spacing? Also I want to do the LS rear brakes and was wondering the same thing. The wheels are about 6.5 backspacing, and I would need about a 2 inch spacer for the wheels to look good in the wheel well. Do the LS rear brakes offer any additional spacing. I know you have to add a 1/4 spacer to center the calipers, but would it offer any more than that.

The braking system is completely stock as of right now.




This is with the stock drum brakes, with no spacer.


This is where I want it to be when it has a spacer on it. Needs about 2 inches of spacing.


Thanks,
Ryan

[LSx_88_Ciera]

What are you wanting to do it is unclear.
3rd gen 'hub' is integrated into the steering knuckle/spindle and uses serviceable bearings not a hub, not to mention it is McPherson strut.

[bl1tzw1ng]

I think he means having a 3rd gen rotor cut down to use as a hub. But I have no answer.

[ryeguy2006a]

What bl1tzw1ng said, as a cheaper alternative you can use a milled down rotor as a hub.

[Randy67]

I have a 1976 Trans Am, and just bought some 19" BMW rims so that I can do the C5 front brake conversion. I was wondering if the 3rd gen fbody hubs will allow for more wheel offset? The front rims are about 5 inches of backspacing with the tires, and I need about a 1/2 inch spacer to make it fit correctly. Would the 3rd gen wheel hubs give any additional wheel spacing? Also I want to do the LS rear brakes and was wondering the same thing. The wheels are about 6.5 backspacing, and I would need about a 2 inch spacer for the wheels to look good in the wheel well. Do the LS rear brakes offer any additional spacing. I know you have to add a 1/4 spacer to center the calipers, but would it offer any more than that.

Thanks,
Ryan

If I remember right, the 3rd gen rotor (as a hub) moves the wheel inboard a little more than the stock rotor. I believe the 3rd gen rotor is used to correctly space the rotor for the caliper. This will move the wheel in a little bit, so you will probably still need a spacer.

As for the LS rear brakes, the spacer everyone talks about is on the caliper mount plate, it goes between it and the end of the axle housing. So it doesn't affect the track width of the axle (flange-to-flange) at all. The rotor does affect the track width a little, but only the width of the rotor itself, nowhere near 2", maybe 1/8-1/4" at most per side. Randy

[Apogee]

It's important to remember that the C5 rotors are slip-on rotors and will require a hub of some sort. Assuming you plan to run this on your original factory GM tall-spindles, the hub combined with the rotor hat thickness is what determines the front track width. The 1982-1987 F-body hub/rotors can be cut down to make a hub, however it will be ~5/16" narrower than your current hub/rotors w/o C5 rotors and only ~1/32" narrower per side with the rotors in place (~.300" hat thickness).

If you wanted to increase the front track width by ~5/16" per side over stock, you could use a 1988-1992 F-body 1LE front rotor which is 5/16" wider and then space the caliper to match. Custom hubs could be a possibility as well if you actually wanted your wheel patterns to match the 5x120mm BMW wheel pattern.

For the rear, you would either need a wider rear axle or some wheel adapters. I would suggest the wheel adapter route so that you could convert from the 5x4.75 to the 5x120mm. LS1 Rear discs only add ~1/8" per side to track width over drums...pretty typical for a disc conversion.

Caliper placement is determined by rotor placement. Period.

Tobin
KORE3

[John Wright]

I took a 3rd gen hub and turned the rotor off of the hub...then the C5 rotor slips up over the lugs. I still had to use a 7/32" shim behind the rim to space it out to clear the C5 caliper.

3rd gen hub

[ryeguy2006a]

Thanks for the feedback. I have been planning on doing the C5 front and LS Rear for a while now, and was just starting to think about getting wheel spacers, and started to think about how this would change the wheel spacing.