H: Hubs, Wheels and Tyres Trevor Southwell re brakes

[fogrider]

Whilst reading my just purchased book " The Vincent Black Shadow", I note a comment relating to Trevor Southwell, who, in the seventies , pointed out the brake shoe pivot points were apparently 1mm from their ideal position.
Anyone know what the proposed correction was ? Sounds interesting.

 

[clevtrev]

Whilst reading my just purchased book " The Vincent Black Shadow", I note a comment relating to Trevor Southwell, who, in the seventies , pointed out the brake shoe pivot points were apparently 1mm from their ideal position.
Anyone know what the proposed correction was ? Sounds interesting.

I merely pointed out my findings and asked for experts to reply, but no one ever did. Draw your own conclusion.

 

[greg brillus]

I think there are absolute limits to which you can improve the stock 7 inch brakes.......Vincent Speet has probably the best solution........The stock shoes are tiny in width and strength........Stronger shoes with good linings (the modern soft stuff is not great) cam bosses that aren't worn oval, pivot (anchor) pins that aren't bent.......plates that run true.......arc the oversized linings to suit each drum and the brakes will be as good as your going to get.........Mind you I've been spoilt with numerous 4 leading shoe large varieties, so No Vincent brake is going to match some of these beauty's......The most effective 4 L/S brake I tried was on a 1200 Egli with an original TZ Yamaha front brake (260mm) with green linings.......this was a 2 finger job that could easily send you over the bars.......

 

[bmetcalf]

The balance beam outrigger support and brake plate gussets also help.

 

[fogrider]

Thanks Trevor, I was a bit slow not realising you ARE Trevor Southwell !
I have done all the mods over the years and I have wondered about the pivot point locations as there seems insufficient self servo. Moving them inboard slightly , towards the centre seemed a possible advantage but it's a lot of machining if it did'nt pay off, or resulted in spragging.
Regards, Terry.

 

[bmetcalf]

Another mod:

https://www.vincentownersclub.co.uk/threads/bert-weisz-brake-mod.14819/#post-134728

 

[Sten Jensen]

Another mod:

https://www.vincentownersclub.co.uk/threads/bert-weisz-brake-mod.14819/#post-134728

I wonder whether the Bert Weisz brake mod only makes the shoes self aligning... Or whether it actually converts the brake to servo action where the leading shoe pushes the trailing shoe hard against the drum.
Did Sealey do something similar ?
My biggest worry with this mod is that all braking force will have to be transferred from the brake shoes to the brake plate through the brake cam and its bearing.
But if it has stood the test of time maybe no need to worry.

 

[bmetcalf]

I'm not sure if anyone but Bert ever tried it.

 

[fogrider]

It's tempting, but I'm not convinced there would be much more benefit than the sometimes recommended "slack" centre hole and tightening the spindle with the brake on.
However, I still think there is potential in the shoe pivot location. In my current read " The Vincent Black Shadow," there is a photo of a brake shoe captioned as having revised geometry - source Vincent spares, but they are not on the shop lists as such. The shop ones look to be stiffened up and that's all ?
Just looked at some Norton 8" SLS front shoes and the pivots are well inboard, surprisingly so, yet that bike does not grab or sprag which makes me think T.S. really did have a point .
This could be a mod worth some effort as I do not like those cheap, nasty, high friction woven linings at all.
It's on the ever increasing project list..........!

 

[erik]

There is the Schmitz 8" twin lead. shoe brake and the 7" Speet brake. Both not cheap but worth the money.And a straight fit.What do you want more? Erik