Go Back   Lateral-g Forums > Technical Discussions > Brakes
User Name

Thread Tools Display Modes
Old 09-12-2018, 07:32 AM
calvin calvin is offline
Junior Member
Join Date: Sep 2018
Posts: 5
Thanks: 2
Thanked 0 Times in 0 Posts
Default 11 or 12" rear rotors?

Doing an RS FastTrack chassis with an LSA/Magnum combo on a 66 Chevelle. I'm guessing weight will around the 3500 mark

As for brake bias would 14" front with 12" rotors be too much/little for this combo? My question is about the rears. 11" or 12" or do you suggest bigger?

Last edited by calvin; 09-12-2018 at 09:12 AM.
Reply With Quote
Old 05-28-2020, 03:36 PM
python python is offline
Join Date: Nov 2012
Location: Amarillo, TX
Posts: 41
Thanks: 0
Thanked 8 Times in 7 Posts

12" will fill the open wheel area better.
Reply With Quote
The Following User Says Thank You to python For This Useful Post:
Spiffav8 (11-30-2020)
Old 11-15-2020, 12:50 PM
pannetron's Avatar
pannetron pannetron is offline
Join Date: Dec 2014
Location: Colorado high country
Posts: 23
Thanks: 40
Thanked 13 Times in 11 Posts

The Baer 13" front and 12" rear brakes on my LSA '66 Chevelle are a good match. The prop valve on my Baer Remaster m/c is set to mid range to balance front/rear braklng. IMHO the 11" rear would be too small unless you're running small diameter wheels and can't fit 12" rotors.
Reply With Quote
Old 11-16-2020, 12:57 PM
572Camaro's Avatar
572Camaro 572Camaro is offline
Senior Member
Join Date: Nov 2016
Location: Central Missouri
Posts: 244
Thanks: 238
Thanked 104 Times in 66 Posts

12” rear rotors all the way.
For the proper appearance
Just use smaller calipers and a proportioning valve.
My two cents
Reply With Quote
Old 11-23-2020, 07:46 AM
Peter McMahon Peter McMahon is offline
Join Date: Sep 2016
Location: Southern Ontario
Posts: 56
Thanks: 3
Thanked 19 Times in 14 Posts

I think the proportioning valve only controls when the rear wheels lock relative to the fronts, not actual braking bias.
Reply With Quote
Old 11-23-2020, 11:41 AM
dontlifttoshift's Avatar
dontlifttoshift dontlifttoshift is online now
Senior Member
Join Date: Oct 2012
Location: Beach Park. IL
Posts: 881
Thanks: 8
Thanked 111 Times in 68 Posts


How could you control wheel lock without controlling bias with a passive mechanical system?

Here is what it looks like on a graph. https://wilhelmraceworks.com/blog/br...rtioning-valve


Support your local hot rod shop!
Reply With Quote
Old 11-23-2020, 12:41 PM
Peter McMahon Peter McMahon is offline
Join Date: Sep 2016
Location: Southern Ontario
Posts: 56
Thanks: 3
Thanked 19 Times in 14 Posts

Well, as explained to me way back when by my auto shop teacher, don't shoot me if I'm wrong,...
the proportioning valve is there to slow the locking of the rear wheels, to make sure the front locks first. After the initial slowing of the locking [ by means of the spring loaded internal portion ] the valve does not perform any more function.
This is incorrect?
Reply With Quote
Old 11-23-2020, 06:53 PM
JKnight JKnight is online now
Lateral-g Supporting Member
Join Date: Nov 2008
Location: Phoenix, AZ
Posts: 719
Thanks: 10
Thanked 33 Times in 21 Posts

You’re accurately describing the function of a different part. It’s a common terminology issue. On cars with front discs and rear drums a “metering” or “hold off” valve was used to delay the engagement of the front brakes until the rear drums could build pressure. It was shaped like a barrel on old GM stuff. You’ll not need this when going to 4 wheel discs. But you will still need a proportioning valve.
Jeff: Project "Rolling Mockup" 69 Camaro SS, AFX, TKO600, Baer GT, etc
Reply With Quote

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

All times are GMT -5. The time now is 12:03 PM.

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2022, vBulletin Solutions Inc.
Copyright Lateral-g.net