rear disc stock gn wheels

searched but didn't find...curious if anyone has data on which rear discs and calipers fit inside aluminum reproduction gn 15'' wheels, 8'' or 7''... TIA
 

1986 Buick GX1

GX1 #001 [The One and Only]
Bear makes a couple kits.





They all say fits 15” wheel and larger, see template.

Summit racing sells several kits as well.


I have an old SSBC kit i’d be willing to sell for $350 shipped.
It’s not for lowered cars, in fact it would work best if running air bags as the calipers have hit the frame at stock height with 2 adults in the back seat. I had cargo coil springs and Bilstien shocks so I understand if you’re not interested.
 

pacecarta

LOGGED OUT
Staff member
saying they'll fit because the manufacturer says fits 15" rims is an assumption that will leave you making calls to the manufacturer and either removing the brake system or having to order new rims
on most rims the drop down(depression) to allow the tire to be installed is in the front and the tire gets pushed on with rim facing up .
gn rims are not like most 15 rims , on the gn the basket is reversed making the dish look deeper. the drop down is in the rear of the rim and the rim needs to be face down to install tire , this moving back of the drop down makes it more like a 14 when it comes to clearing a brakecaliper
. the gn aluminum is made the same way and clearance for brakes is still an issue

i can tell you that the gn rim will fit with strange 4psion disc brakes if you have long studs and run a 1" spacer , without the spacer youd need a different rim
 

jfsram

Member
That makes total sense Pace. I am experiencing that right now.
The disc that came with my Moser Engineering rear has the big Ford bearing and Ford flange on the end. Came with single piston 11" disc brakes. Same caliper as a Cadillac Elderado.

They will not clear my 87 GN steel wheel but my 15" Centerlines fit.

I am also considering 16" GNX wheels but unsure of offset since I have no fender flare. Also tire selection is slim in 16"
 

1986 Buick GX1

GX1 #001 [The One and Only]
That makes total sense Pace. I am experiencing that right now.
The disc that came with my Moser Engineering rear has the big Ford bearing and Ford flange on the end. Came with single piston 11" disc brakes. Same caliper as a Cadillac Elderado.

They will not clear my 87 GN steel wheel but my 15" Centerlines fit.

I am also considering 16" GNX wheels but unsure of offset since I have no fender flare. Also tire selection is slim in 16"
Only true GNX wheels will have an offset that sticks out too far, needing flares.
GTA front wheels have a close offset and will work, but to me they looked sucked in a bit.
The GTA rear wheels have too much (positive) offset and will rub the frame.

The 18” GNX style wheels from venders are made specifically for our cars and fit no problem.

I believe the 16” GNX style wheels from vendors have the GTA front offset, but it’s been awhile and I’m not quite sure.
You are definitely right about 16” tire choices.
 
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