Girder forks brakes

The rear Commando drum brake is almost identical anyway.  They use the same shoes.  The only difference is that the shoe anchor pins are longer and are connected at their outer ends. You can't fit the connector to prewar brakes unless you were to change the pins (or backplate).

Modern Commando shoes fit but there are softer and more effective options available. Softer shoe materials (e.g. from Villiers Brake Services and others) are a worthwhile improvement.

In theory, drum brakes should be just as good as discs.  In practice that's not true. Heat is the first enemy of drums, although the Singles don't have as much horse power to shed.  Friction in the cables and levers is another.  A longer actuator arm on the backplate might be worth trying?

It would be interesting to know about alternative front fittings.  But the rear drum brakes are the same...so there's nothing to gain by going Commando.

The rear on girder-rigids can usually be locked fairly easily. The drum benefits from the chainwheel around it and there is lots of leverage (although you could gain more by using a WD16H pedal (and probably footrests too, unless you have big feet).

Over-greasing is a great enemy of the Norton hubs, as it finds its way onto the shoes.

A heavy duty front brake cable can improve matters, and although we're not supposed to say it, the original woven asbestos shoes work much more effectively on this size of drum than anything that has been made since. Hard grey industrial friction material doesn't seem to work well.

As to the front brake, be careful about beefing it up too much, you might be putting too much strain on the girders, which will not have been designed with those sort of forces in mind.

As Richard says above, there is a simple solution that we cannot use. My 16H has excellent brakes.  The front brake has startled following Commandos.  Its linings haven't been renewed for at least 30 years and probably a lot longer. With 6000 miles on the clock, they might have come from Bracebridge Street.  Contrary to what modern journalists often write, the road testers of the day were not necessarily lying when they praised the brakes in these old machined.

The Inter on the other hand was frighteningly bad until I had modern softer linings fitted.  It's still not as good.

The previous owner added non standard reversed levers. They have a longer distance from pivot to cable, so he was forced to fit a much longer lever on the backplate to compensate.  I suspect the lever could be longer still.  That might be worth a try. I don't know how he made the correct shape hole in the lever.  I think it's not the exact oval shape from a simple slot mill.

The modern soft linings are also woven somehow.

Next we'll be discussing lathe turning drums and linings. Norton drums are cast malleable iron, not pressed steel. They are not easily distorted by wheel building (according to a long time professional wheel builder who spoke to our club a few years ago).  And there's only so much metal you can safely remove.  The people who did my linings said not to do it normally. They fit fine.

hello

when i replaced the old asbestos shoes on my rear brake. i compared the old and new linings side by side the new linings didnt follow the same radius as the old ones.  when trying the new ones into the brake drum they would rock backward / forwards. as the old shoes were as new, no wear on them. i just took some off the new linings to suit, to make same. seemed a more positive brake, not spongy feel. its a  pity the brake shoe pivot points arnt ajustable, eccentric wise. to centralise the shoes better.

Barry

I'm with David Cooper on the subject of drum brakes and girder forks.

My '37 Model 50 will lock both wheels with Villiers replacement normal road use (re) linings.

However, my '35 Inter had a hopeless front brake and my one and only (moving) tumble in 50 odd years riding was due to front brake fade, during the Irish Rally, going up hill!. Front brake drum skimming and profiling replacement shoes to match made no difference at all and has left an already thin drum even thinner. Again, Villiers relined brake shoes for the front have given me effective brakes at that end and boiling the back ones in washing powder sorted the back ones. 

  I have no connection with Villiers services at all, I just wish I had tried their linings on previous pre war bikes and not learnt the hard way. I seem to recall that relining my old shoes was approximately £22 incl. p&p.

With  single leading brakes the leading shoe wears  faster. If the shoes are interchangeable I swap them round to have the thickest shoe in the leading position.  I measure the shoe thickness with my vernier calipers . After a few heavy applications the brakes work fine . My current linings are almost on the rivets and the brake works better than ever , I am loth to fit my new shoes as I know its going to take a while to get the same result.

Some observations (better than watching even more Xmas TV)...

Both brake shoes are pushed out exactly the same amount at the same time by the mechanical cams.  So surely they must wear at the same rate?  Since the rate of wear is caused by the rate of work they do, they must do the same work.  The leading shoe tries to do more work because of the servo effect, but it can't do so because, if it wears more quickly, it runs out of contact force.  The result should be the average of a twin leading shoe and a twin trailing shoe brake.

If a hydraulic double ended piston was used, the leading shoe could work harder, and wear quicker.  Some have done hydraulic conversions, but a twin leading shoe gives more force for less complication.

The servo effect with leading shoes has the drawback of not allowing sensitive control.  Mine can snatch savagely when it's not been used for some time and a film of rust has appeared in the drum.  It threw me off once, at low speed 100 yards from home. One of the biggest advantages of discs is that they don't have any servo effect.

The sls has less servo and seems to give a more predictable brake.

...but if an sls brake is used for long enough without maintenance the leading shoe will eventually run out of contact force almost completely, leaving effectively a single trailing shoe to do all the work. This is why it is good practice to swap the shoes over every so often, before there is significant difference in lining thickness.

My CS1 has an 8" BSA half width hub fitted by the PO. I believe the linings were machined to match the drum radius. This is an extremely effective brake in the dry, but like David's worryingly grabby in damp conditions. Not sure if this is due to rust or a characteristic of the lining material. Norton also fitted an 8" half width hub to some models (I think this first appeared on Inters and is sometimes referred to as an International brake). If someone wanted to upgrade the front brake using Norton components this might be the way to go. It would still need some engineering effort (new spindle and anchor point) to adapt it for the girders.