Board logo

Bias peddal setup query
steve m - 20/5/14 at 06:36 PM

I up

I have an OBP setup installed in the 7, but am rather confused in how to set it up for the best braking
Ive read the blurb, and still confused

current setup is .625 fronts with 4 pot calipers
and rear is .7 on normal ford 7 drums

I currently have the balance bar equal to give the same pressure to both cylinders

which portion of the balance bar should be longer the front or back ?

Steve


minitici - 20/5/14 at 06:41 PM

If you want to move the bias forward, the pivot point needs to move closer to the front cylinder.
i.e. the bar will be shorter on the front cylinder side.


adithorp - 20/5/14 at 06:42 PM

Whichever cylinder the bearing is closest to will have to most force applied to it.


steve m - 20/5/14 at 06:59 PM

Thanks guys, and confirms what I was thinking

steve


Dusty - 20/5/14 at 10:46 PM

The other point you need to consider is the travel of m/c piston. Usually the piston for the rears travels about 0.5 cm and the piston for the fronts about 2cm. As a result the balance bar is not set at right angles to the piston operating rods but angled forward to the rear m/c and angled back to the front m/c. If this is not done the bar runs out of pivoting movement when the rears are full on and may not be able to apply pressure to the fronts. This is done by having a longer pushrod on the fronts. Difficult to explain. Pic to be added in a minute.
[img] Bias set
Bias set
[/img]


[Edited on 20/5/14 by Dusty]


Mistron - 3/6/14 at 10:35 PM

Are these the 'standard' bore sizes for a twin M/C set up?

I have Spitfire discs at the front and Riley 1.5 drums at the rear

Cheers,
Al


scudderfish - 4/6/14 at 10:03 AM

quote:
Originally posted by Dusty
The other point you need to consider is the travel of m/c piston. Usually the piston for the rears travels about 0.5 cm and the piston for the fronts about 2cm. As a result the balance bar is not set at right angles to the piston operating rods but angled forward to the rear m/c and angled back to the front m/c. If this is not done the bar runs out of pivoting movement when the rears are full on and may not be able to apply pressure to the fronts. This is done by having a longer pushrod on the fronts. Difficult to explain. Pic to be added in a minute.
[img] Bias set
Bias set
[/img]


[Edited on 20/5/14 by Dusty]


Gah! Whoever built my Fury shortened the wrong one! Time to go diving in the footwell to swap the pushrods over......


britishtrident - 4/6/14 at 10:24 AM

Really really important the push on the master cylinders should be adjusted to roughly the same length do not attempt to take up longer travel in one cylinder by jacking one out excessively.
The side clearance between the forks and the tube on the pedal should be sufficiently wide to allow the balance bar to move freely in normal operation but put pressure on one brake circuit in the event of failure of a single circuit.

[Edited on 4/6/14 by britishtrident]