Rear Brake Question

Dave Borror · 09-14-2011, 09:33 PM

Thinking about wilwood rearconversion. 10 bolt 8.5 corp. rear end with spool drum brakes 71 B body chevy. This is a stocker build so it has 9x30s Taking in consideration roatating mass/drag which is faster drum or rotor.

Alan Roehrich · 09-14-2011, 10:04 PM

The really lightweight disc brake stuff will be quick, the question will be is it enough to stop your car. You may not find an aluminum drum set up that will fit your car, at the very best, they'd have to be re-drilled.

That's a good sized car for an 8.5" 10 bolt. Perhaps a later model 8.625" rear end could be adapted?

Dave Borror · 09-14-2011, 10:31 PM

Front brakes no problem . Since the b body is 5x5 and their is no mods spindle for the 5x4.75 I just redrilled 12"rotors for 3" 1/2 20 screw-in studs. backs are 33 spline mosers and spool.5x4/75.drums are redrilled and cross drilled.never had any problems with the rear bracket racing. I'm building the car now for stock so i,m looking at any edge in can get on rotating mass/friction.etc.I ran alum. drums on my last stocker but I was wondering about which would be faster on the rear since it is taking roatating hp being the drive tires. I heard once drums were faster but ???

Alan Roehrich · 09-14-2011, 11:57 PM

Well, I would almost bet that if you can find something to work, or have something modified, the front is where you'll find the real gains. It's weight, mostly unsprung, off of the right end, as well as rotating mass. It may be hard to find anything though.

You can put any end on the rear axle, and that allows you to have a lot of options back there. That end is easy, although if you've already bought axles you may be behind the 8 ball.

Dave Borror · 09-15-2011, 07:29 AM

The rear end is the 8.5 O&B factory non C clip.As strong as a 12 bolt with .050 biger axles. There-fore Wilwood, make a bolt on kit..Thats no problem,my question is is it worth the investment and is there any real gain. I have always heard pros and cons I know ever car is a different senerio. It may be the same as light weight spool vs regular spool debate,but rotors and drum drag effeciency, rotating mass,if any.Thanks for any input or opinions. Dave

09-14-2011, 09:33 PM	#1
Dave Borror Junior Member Join Date: Nov 2010 Location: Hide Away Hills Ohio Posts: 24 Likes: 0 Liked 0 Times in 0 Posts	Rear Brake Question Thinking about wilwood rearconversion. 10 bolt 8.5 corp. rear end with spool drum brakes 71 B body chevy. This is a stocker build so it has 9x30s Taking in consideration roatating mass/drag which is faster drum or rotor.

09-14-2011, 10:04 PM	#2
Alan Roehrich Veteran Member Join Date: May 2006 Location: Murfreesboro TN Posts: 5,111 Likes: 1,570 Liked 1,814 Times in 413 Posts	Re: Rear Brake Question The really lightweight disc brake stuff will be quick, the question will be is it enough to stop your car. You may not find an aluminum drum set up that will fit your car, at the very best, they'd have to be re-drilled. That's a good sized car for an 8.5" 10 bolt. Perhaps a later model 8.625" rear end could be adapted? __________________ Alan Roehrich 212A G/S

09-14-2011, 10:31 PM	#3
Dave Borror Junior Member Join Date: Nov 2010 Location: Hide Away Hills Ohio Posts: 24 Likes: 0 Liked 0 Times in 0 Posts	Re: Rear Brake Question Front brakes no problem . Since the b body is 5x5 and their is no mods spindle for the 5x4.75 I just redrilled 12"rotors for 3" 1/2 20 screw-in studs. backs are 33 spline mosers and spool.5x4/75.drums are redrilled and cross drilled.never had any problems with the rear bracket racing. I'm building the car now for stock so i,m looking at any edge in can get on rotating mass/friction.etc.I ran alum. drums on my last stocker but I was wondering about which would be faster on the rear since it is taking roatating hp being the drive tires. I heard once drums were faster but ???

09-14-2011, 11:57 PM	#4
Alan Roehrich Veteran Member Join Date: May 2006 Location: Murfreesboro TN Posts: 5,111 Likes: 1,570 Liked 1,814 Times in 413 Posts	Re: Rear Brake Question Well, I would almost bet that if you can find something to work, or have something modified, the front is where you'll find the real gains. It's weight, mostly unsprung, off of the right end, as well as rotating mass. It may be hard to find anything though. You can put any end on the rear axle, and that allows you to have a lot of options back there. That end is easy, although if you've already bought axles you may be behind the 8 ball. __________________ Alan Roehrich 212A G/S

09-15-2011, 07:29 AM	#5
Dave Borror Junior Member Join Date: Nov 2010 Location: Hide Away Hills Ohio Posts: 24 Likes: 0 Liked 0 Times in 0 Posts	Re: Rear Brake Question The rear end is the 8.5 O&B factory non C clip.As strong as a 12 bolt with .050 biger axles. There-fore Wilwood, make a bolt on kit..Thats no problem,my question is is it worth the investment and is there any real gain. I have always heard pros and cons I know ever car is a different senerio. It may be the same as light weight spool vs regular spool debate,but rotors and drum drag effeciency, rotating mass,if any.Thanks for any input or opinions. Dave