[RGT]

As I swapped out my enemic 6' single leading shoes brake assy. with a 7" twin leading shoes set up(and am much happier with my braking btw) I was looking at the working mechanism and am surprised that these brakes use a fixed pivot. In cars and trucks drum brakes are partially self actuating due to having a floating pivot, which forces the leading edge of the trailing shoe(if that makes sense) to do some work without requiring additional input force(thus being called self actuating. Even the newer style 7", with its twin leading shoe actuators only applies the force I can put in by applying the lever. Since the shoes are located at their actuation points there is no self actuating occuring as the shoes are not allowed to cock in the bore and self apply. The 7" is an improvement but I could not apply enough pressure to lock the front tire up if I wanted to. I am curious if other drum brake bikes use a self actuating design?

[motomataya]

As far as i have seen,all bikes have a stationary Pivot point. Thats why they need two levers per brake to get decent power. This setup also means they dont work going backwards. Like when you are unloading from a truck, or trailer.

[Geirskogul]

If you can't put enough pressure to lock up the front tire no matter what, then something is very, VERY, VERY wrong.  I can lock my front tire up like *snap* that if I wanted to, while moving forward.  Backwards is another matter - it takes a bit more force, but I can still lock the front tire up.