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front drum brake
Posted: Thu Feb 21, 2013 2:04 pm
by Motorhead
OK I'll bite the bullit, l got another set of brake cam arms to streach
how many votes for 1/4 longer
how many votes for 1/2 longer
most easy cluth adds 1/4 and a wheel
Re: front drum brake
Posted: Thu Feb 21, 2013 2:37 pm
by robert
3/4" or more.
Re: front drum brake
Posted: Thu Feb 21, 2013 3:27 pm
by Major Softie
It's not that hard to predict the results. Just take the length of the stock arm (shaft center to cable point) and divide the proposed change by the stock length.
Example
IF the stock lever was 4" long, and you were considering adding 1/2":
.5 / 4 = .125
So, a 4.5" lever will have 12.5% more mechanical advantage than a 4" lever
Re: front drum brake
Posted: Thu Feb 21, 2013 6:09 pm
by Ken in Oklahoma
Major Softie wrote:. . . So, a 4.5" lever will have 12.5% more mechanical advantage than a 4" lever
And you'll have 12.5% less rotation (approximately) of the brake cam. If something like that would be an issue then a person would want brake cables, in particular the surrounding coiled wire under the jacket, to be in good shape.
That happened to me back in the olden days on my Husky 360 MXer. I wasn't satisfied with the front wheel braking so I made the lever arm longer. I probably wasn't bright enough then to realize that a stretched coils here and there could have contributed to my lack of success.
Of course Husky front brakes were notoriously feeble anyhow, so in a sense, I guess, I was trying to make a silk purse out of a sow's ear.
Ken
Re: front drum brake
Posted: Sun Feb 24, 2013 12:06 am
by jjwithers
Please post photos?? I'd love to see how you are extending the arms. It has been on my 'wish list' for a long time but haven't even come close to crossing that bridge yet.
Re: front drum brake
Posted: Sun Feb 24, 2013 11:37 am
by Motorhead
there are 2 ways to do it
weld the space added
use a steel tube, say 5/8 0blong the tube to fit the cut in the middlle brake parts add JB WELD to fill any gap rivet the the pices with steel rivits
it can then be painted
picturesmadybe if I get some help
Re: front drum brake
Posted: Mon Feb 25, 2013 7:47 am
by pkboxer
How about using 2 arms to make up one longer arm so there is only one seam and not two? More sacrificial parts but would look cleaner.
Or are you extending both arms? I guess that would take 4 arms to do....
Re: front drum brake
Posted: Mon Feb 25, 2013 12:57 pm
by Major Softie
Then, of course, there is the most cafe solution of all: fabricate one from scratch.
Re: front drum brake
Posted: Fri Mar 01, 2013 5:34 pm
by jjwithers
Major Softie wrote:Then, of course, there is the most cafe solution of all: fabricate one from scratch.
Replicating those spline teeth would be REAL tricky...
Re: front drum brake
Posted: Fri Mar 01, 2013 7:18 pm
by Major Softie
jjwithers wrote:Major Softie wrote:Then, of course, there is the most cafe solution of all: fabricate one from scratch.
Replicating those spline teeth would be REAL tricky...
Yep. I have no idea how it would be done, but I'm sure there's someone here (maybe Ken) who's got some ideas.