I have wondered though... if the NON leading shoe should be a little more worn away than the leading primary (if you like) shoe? So that better contact and stopping power on the leading shoe can be achieved. Any ideas on this anyone? Because, thinking about it... If the non leading shoe contacts the drum first then that shoe's contact would lessen the leading shoes friction on the drum resulting in a weaker operating brake.
sadly many of our brake issues relate to poor set up rather than design, however the question of trailing vs leading shoe interests me. The trailing shoe has less friction so would typically wear less if given the chance, however the lever lift will force comparable wear on both; so rather the effort going into the trailing shoe is largely wasted.
If you look at the daytona bikes of the mid fifties, BSA changed the lever arm direction around on the front wheel so it faces forward, this was also done on the later pre unit A series on the back wheel where the rear lever runs under rather than over the hub. What this does is increases the lift on the leading shoe as the brake cam inner edge lifts the leading shoe and the outer edge lifts the trailing shoe. The inner face of the cam (if parallel) lifts that shoe relatively higher.
The other thing of course done on the last of the A10's was floating brake shoes which enables the brakes to initiate a servo action, which could cause biting, so the pads were both offset and chamfered.
Am considering what brakes to run on my road A10 and have not come to a conclusion. -Not urgent though as its still in bits.
My sidecars running paired up single sided 8" SLS, extremely effective but too heavy for a solo.