Rear drum brake size

patrick · Post by **patrick** » Fri Nov 24, 2006 4:03 pm

I pulled off my wheels and noticed my rear drums are 10 inches. Was this ever stock on a '73 Road Runner, or did they all come with 11-inch brakes? Every big block I ever owned has had the 11-inch fluted brakes. When I go to Napa's site, it lists 11-inch brakes, unless I put in "Satellite" or something else.

That being said, I converted to 11.75-inch front discs. Is there any point in upgrading the rears since I want to replace everything anyway? (Of note, 10-inch brake parts tend to be cheaper.) I would have to find 11-inch backing plates also, further delaying the project.

Suggestions? Thanks!

1bluegtx · Post by **1bluegtx** » Sat Nov 25, 2006 12:16 am

Well since most of your braking is done with the front discs i do not think you will see much improvement converting to 11 inch drums.

BRIAN

road chicken · Post by **road chicken** » Sun Nov 26, 2006 2:19 pm

10" were the standard fair out back. If you had Drums on all 4 corners ( like mine did) on rr/gtx then you got 11" all around. With the front disks you got 10" out back because the disks are so much superior to the drums capacity.

So nope- totally normal.

patrick · Post by **patrick** » Sun Nov 26, 2006 2:41 pm

Thanks for the info! I will be keeping it 10 then...

I wonder if there was more tendency for the rear to lock up with front discs and 11s on the back versus 10s? Or maybe they just didn't feel it was necessary to put 11s with the discs and it was an economic decision to maximize profit.