Brake Bias - Balance Bar Issue

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jimcroisdale
0
Joined: Wed Nov 09, 2016 11:47 am

Brake Bias - Balance Bar Issue

Post by jimcroisdale » Tue Mar 13, 2018 10:06 am

Hi all,

Designed a balance bar brake bias system for my gravity racer. Finally got it all hooked up and this happens:

https://www.youtube.com/watch?v=FApsRy7TE90

I can only think that the cylinder pushrods are allowing too much non linear motion (im using cheap quad bike cylinders) but looking at the design of Wilwood/Girling type cylinders they look very much the same - pushrod with domed end sitting against the piston and held in place with a washer and circlip.

Looking at it, what the balance bar is doing seems perfectly reasonable - moving up and down at the ends rather than pushing against the spring. But what makes my system so different and how do other systems stay so linear?

Any ideas?

Jim

Jolle
93
Joined: Wed Jan 29, 2014 9:58 pm
Location: Dordrecht

Re: Brake Bias - Balance Bar Issue

Post by Jolle » Tue Mar 13, 2018 10:56 am

jimcroisdale wrote:
Tue Mar 13, 2018 10:06 am
Hi all,

Designed a balance bar brake bias system for my gravity racer. Finally got it all hooked up and this happens:

https://www.youtube.com/watch?v=FApsRy7TE90

I can only think that the cylinder pushrods are allowing too much non linear motion (im using cheap quad bike cylinders) but looking at the design of Wilwood/Girling type cylinders they look very much the same - pushrod with domed end sitting against the piston and held in place with a washer and circlip.

Looking at it, what the balance bar is doing seems perfectly reasonable - moving up and down at the ends rather than pushing against the spring. But what makes my system so different and how do other systems stay so linear?

Any ideas?

Jim
I would limit the motion of the point on the brake lever itself. no up and down, just left-right.

gambler
1
Joined: Sat Dec 12, 2009 6:29 pm

Re: Brake Bias - Balance Bar Issue

Post by gambler » Tue Mar 13, 2018 3:07 pm

jimcroisdale wrote:
Tue Mar 13, 2018 10:06 am
Hi all,

Designed a balance bar brake bias system for my gravity racer. Finally got it all hooked up and this happens:

https://www.youtube.com/watch?v=FApsRy7TE90

I can only think that the cylinder pushrods are allowing too much non linear motion (im using cheap quad bike cylinders) but looking at the design of Wilwood/Girling type cylinders they look very much the same - pushrod with domed end sitting against the piston and held in place with a washer and circlip.

Looking at it, what the balance bar is doing seems perfectly reasonable - moving up and down at the ends rather than pushing against the spring. But what makes my system so different and how do other systems stay so linear?

Any ideas?

Jim
The tube in the pedal is too narrow, it needs to come all the way out to where the pushrods are strait , minus the thickness of 2 swash plate washers (like hard medium thick fenderwashers) look at a pic of a wilwood twin pedal assembly. I set them up with about .090 gap total) They will always flop a little, just keep adjusting untill you get the feel you want. You may also want to make sure the center line up and down is strait.

jimcroisdale
0
Joined: Wed Nov 09, 2016 11:47 am

Re: Brake Bias - Balance Bar Issue

Post by jimcroisdale » Wed Mar 14, 2018 11:13 am

Yes, you are correct. After looking some more at setups online I realised that the master cylinders were spaced too far apart. Ive moved them closer so that they are almost touching the central tube and it works a treat now. :-)

jimcroisdale
0
Joined: Wed Nov 09, 2016 11:47 am

Re: Brake Bias - Balance Bar Issue

Post by jimcroisdale » Thu Mar 15, 2018 10:17 am