H: Hubs, Wheels and Tyres Eight inch brake ?
- Thread starter Julian R.
- Start date
Who determined the `correct` geometry for the shoe, as I`m still waiting for the `experts` to reply to my article in MPH, what was it 30 years ago ? I Tried several different layouts, but never achieved the result I wanted.
Good question as I said that's what I belive but it was in the end only what I was told
That seems to be a good brake. Both shoes rest on the cam, but the back side of the cam is a constant radius, so it does not move the shoe on the radius when the cam is turning. The front side is a flat cam and that shoe moves when the cam turns. There is a large washer to hold the shoes in place, but as you say they can slide.
On Burt's mod the shoes can move in all directions meaning that the leading shoe can move away from drum (this cannot happen with the Triumph design). The hope is that the trailing shoe will push away from the drum also and push the leading shoe back onto the drum as they are linked together. It is a guess, but the Triumph design may have been done as a semi-floating shoe because they did not want both shoes to be able to retreat from the drums, even a bit.
David
Enjoying this thread. I wonder if the old "fabric" asbestos linings were much grippier, but wore out quicker. Another case of gain with one hand and lose with the other. Being new to Vincents, I still struggle to set up my brakes, the lever is coming right back to the bar, and I have reasonable braking, but my hand is not comfortable with such a small squeeze at the end of the movement. I run out of strength as my hand closes up. So another problem with lots of movement to achieve the necessary force?
Tom, there are very few Vincent's on the road with really good original brakes. Can I ask if you set up the shoes on the plates with over-sized linings and then turned them down in a lathe to match each drum. Just getting shoes re-lined and install as they are will result in poor brakes. The shoes/linings are very small so they need all the help they can get. Everyone lays blame with cables, levers, balance beams etc, but it is the actual brake linings and their match to each drum that makes all the difference. Cheers................Greg.
Tom,
The linings today tend to be much better, but they are generally not offered for drum brakes because nobody uses drum brakes.
On the lever, I usually do it the way Greg does, start out with the linings just short of touching the drum and I try and take all the play out of the system so the lever does not have to take it up before the shoes hit the drum.
I take it you measured your lever pivot distance? It should be 7/8" from the lever pivot center to the center of the cable barrel. If it is longer than that the lever will touch the bar for sure.
Reasonable braking is quite good!
David
The linings today tend to be much better, but they are generally not offered for drum brakes because nobody uses drum brakes.
On the lever, I usually do it the way Greg does, start out with the linings just short of touching the drum and I try and take all the play out of the system so the lever does not have to take it up before the shoes hit the drum.
I take it you measured your lever pivot distance? It should be 7/8" from the lever pivot center to the center of the cable barrel. If it is longer than that the lever will touch the bar for sure.
Reasonable braking is quite good!
David
7/8th has a higher lever ratio than 1 1/18th so lever will not come back so far but force on the cable will be reduced.
Bill
Bill, is it not the case that the closer the centres of the cable nipple and the pivot point, the cable travel distance will be less but the force transmitted will be more, I hope this is the case as I fitted a 7/8" lever to my Comet that is fitted with a Honda clutch in an attempt to make the heavy lever action more acceptable, but you sacrifice some lift in doing so.
the only way
