66luvr

I added front disc using factory 72 style, all GM original parts on the 67 convertible. Before the change I had little to no tire rub with the 17x7 wheel/tire combo with 215-60-17, 27" tall, tires and a 4" backspacing on the wheels. After the change I have Lots of tire rub. I think I have heard this kind of changeover pushes the wheel out some, anyone know for sure exactly how much? If this is correct, can you tell me if there is a disc changeover that does NOT push the wheels out?


Thanks,

joe_padavano

The disks space the wheels out a fraction of an inch, not an "inch or so". How this affects your wheel/tire combo is impossible to tell since you didn't tell us tire size (it's not the wheel that's rubbing, it's the tire) nor did you tell us offset on the wheel.

JPMDaddy

I put an SSBC disk brake conversion kit on my 66 El Camino - not supposed to change geometry - but my track is now about an inch wider which caused my 235/60x15 front tire to rub slightly if I went through a turn with a dip in the roadway -


went to 225/60x15 which helped a little

jag1886

I used ECI brake conversion on my 65 and it does not move the wheels out. It is more expensive than a lot of conversions but is a quality set up and the old guy that builds them is a real nice guy.
My 65 already had close clearance before I did the conversion and nothing changed after it was done.

oldcutlass

Where is it rubbing?

66luvr

Fender lip.
As I said, I put the wheels and tires on last year. They are 17x7 with 4" backspace. I had no wheel rub, well if you had the wheel cut all the way and went up on a big bump too fast it might touch, very minor. Now it rubs a lot of the time, just turn into an alley and big time rub. There is as much difference as night and day, before and after the disc conversion. I am well aware changing tire size could help, not the question I posed. The before and after tells me adding the disc brakes pushed the wheel out closer to the fender lip which causes the rub. I was really hoping someone had a definite answer of how far the wheel was set out by the disc addition. Maybe I didn't phrase the original post well.
I am ready to change the disc brakes to the mentioned ECI parts and original spindles because I know there is a difference in the wheel / tire location now compared to before.
The 14" tires I took off the car were 26" tall, the 17" tires I put on are 215/60/17 and are 27" tall. The rear tires are 235/60/17 and are 28" tall. I know the tire width is a problem, but in 17" size skinny is not an option I have found.


Thanks to all,

oldcutlass

I was just curios as to where it was rubbing. I understand that some disc brake setups may move the wheel out some distance. Did you call the manufacturer and ask them what they suggest?

66luvr

GM is the manufacturer. All factory original parts, single piston calipers.
I will find out how much the things I did pushes the wheel out. The parts are all here, not hard to do a little measuring.


Thanks,

edzolz

I have done this conversion many times and never had any problems with tire offset. Maybe the inner bearing race is not seated all the way down in the bore. That is the only thing that could make the tire offset different that I can think of. Or the alignment isn't set correctly with the camber angle off.

1964f-85

The 68-72 disc brakes on a 64-67 move each wheel out 1/2 inch farther than the original drum set up. I used the ECI narrow track set up, it moves each wheel in half an inch more than the original drum, netting you a full inch on each side. This is a must on the 64-67 unless you are running stock wheels.

66luvr

I completely agree, the GM single piston disc do indeed push the wheel/ hub/ tire, however you wish to state it, out one half inch on each side. As you say one inch total added to the track. I measured it for myself today, not hard to do with all the stuff present.
So as you suggest I am changing to the original drum spindles and ECI components, I want my inch back and may go for the extra inch also, I'll discuss that with ECI.


Thanks to all, no more guessing. One said a fraction of an inch which is completely true, a pretty large fraction though.

1964f-85

Their kit uses off the shelf GM rotors and calipers, i even kept my 14" wheels.
Its easy to install and is well made. You will love it!