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Re: Brake Lever - "Mechanical Advantage"?

Posted: Fri Feb 08, 2013 11:18 am
by Whites
We have mounted out new bias box next to the sidecar wheel and decided to make a new brake pedal, with a 7:1 ratio.

I will post a picture once the welding is complete.

Re: Brake Lever - "Mechanical Advantage"?

Posted: Mon Feb 18, 2013 12:23 pm
by Whites
For anyone who is interested, this is what we ended up doing with our brake lever.

Still needs chopping down and a foot pedal attaching, but you get the idea.
brake-lever-1.jpg
brake-lever-2.jpg
brake-lever-3.jpg

Re: Brake Lever - "Mechanical Advantage"?

Posted: Wed Feb 20, 2013 9:52 am
by powerhouse
as a matter of interest what is your distance between crank and front spindle centerlines?
can you post pics of engine rear mounting points and engine in chassis.
ive moved my engine forward with fantastic results.i built new tubes on ours as the bells and terry designed

Re: Brake Lever - "Mechanical Advantage"?

Posted: Wed Feb 20, 2013 10:33 am
by Whites
The engine isn't mounted yet, so can't get the measurements until it is. Still got a fuel tank to make and fit yet.

I will get a pic of the engine rear mounts tonight, and a pic of it mounted once it is in.

Re: Brake Lever - "Mechanical Advantage"?

Posted: Wed Feb 20, 2013 11:27 am
by alanw
Looks like youve got much more than 7 to1 ratio probably a lot more than you will need, dont shove too hard you will lock everything up.

Re: Brake Lever - "Mechanical Advantage"?

Posted: Wed Feb 20, 2013 11:31 am
by Whites
The lever is actually too long in the picture. It is now cut off and a foot pedal attached, at a 7:1 ratio.

Re: Brake Lever - "Mechanical Advantage"?

Posted: Wed Feb 20, 2013 12:02 pm
by powerhouse
Whites wrote:The lever is actually too long in the picture. It is now cut off and a foot pedal attached, at a 7:1 ratio.
have you got short stroke cylinders? as it looks as if you may have alot of foot movement compared to cylinder stroke.
good job though :) .
but i does look like you may run out of pedal stroke before brakes are fully applied.or it could be the photo :) hope im wrong

Re: Brake Lever - "Mechanical Advantage"?

Posted: Wed Feb 20, 2013 2:11 pm
by Whites
powerhouse wrote:
Whites wrote:The lever is actually too long in the picture. It is now cut off and a foot pedal attached, at a 7:1 ratio.
have you got short stroke cylinders? as it looks as if you may have alot of foot movement compared to cylinder stroke.
good job though :) .
but i does look like you may run out of pedal stroke before brakes are fully applied.or it could be the photo :) hope im wrong
I hope you are wrong also :o

I got much advice about the correct ratio to go for, between 5:1 and 8:1. We decided to go for 7:1. Hopefully the brakes work fine. If not we have more work to do.

Re: Brake Lever - "Mechanical Advantage"?

Posted: Wed Feb 20, 2013 2:56 pm
by G JONES
Whites wrote:I got much advice about the correct ratio to go for, between 5:1 and 8:1. We decided to go for 7:1. Hopefully the brakes work fine. If not we have more work to do.
There's a couple of things that will affect it - if you're using CP2623 M/Cyls - they have very short "distance to cutoff" (I think that's what it's called) - just means your pedal will not need to move far before the brakes work - not sure what you have on your bike - the M/Cyl bore size will also make a difference - also how big your feet are :D - if you've got short feet - the distance you can push a pedal in the kneeling position will be limited - it's not like a solo - where you can move your leg to stamp on the brakes - you only have the distance your ankle will move...

Re: Brake Lever - "Mechanical Advantage"?

Posted: Wed Feb 20, 2013 3:18 pm
by powerhouse
useing the 0.624 [5/8]mc's your lever should be 210-215mm from pivot to the end and 40mm from pivot to the pushrod----you would have been better off useing cp2623's mc's as the shut off is closer so less travel on lever :D --------gatey

Re: Brake Lever - "Mechanical Advantage"?

Posted: Thu Feb 21, 2013 12:15 pm
by Whites
Distance from pivot to pushrod is 52mm. Distance from pivot to pedal end is 360mm.

Here is some pictures of the chassis, to show the engine mounts.

Both
Chassis.jpg
Front
front mounts.jpg
Rear
Rear Mounts.jpg