At least he got the title of his thread right.......and I see no difference between a drum or a disc on the rear. Either one will lock it up easily, the real work is up front.
Yes, of course, the majority of braking is done by the front brakes. With the back brake, its not desirable to be able to lock the rear wheel. The maximum deceleration occurs before lock up happens..............that's why ABS is certainly a good thing to have, on 4 wheel vehicles, and probably 2 wheel bikes as well.
I've had cars with 4 wheel drum brakes. How did they brake in an emergency from high speed....................absolutely terrible, not safe at all. Throwing out an anchor would have been better.
I've had cars with front disc and rear drums. How did they brake in an emergency..............reasonably well, so I felt some degree of safety. However, the front discs did all the braking. The rear drums never did any braking at all, because the self adjusting mechanisms just never worked, even though I serviced them regularly. Once a small amount of the shoes was worn down, there was no rear braking.
My present car (Toyota Camry) has ABS 4 wheel disc brakes, with engineering features such that the braking forces are balanced with just the right amount of hydraulic pressure going to the front and lesser pressure to the rear. This is the first vehicle I have ever owned that actually applied appropriate braking forces at all 4 wheels.
How is the regular and emergency braking..................very powerful, just superb, such that you feel very safe even at speeds above the legal limit.
I recall driving my 305 cc Yamaha 2 stroke. It had drum brakes front and rear, and braking was just barely acceptable, with not much of a safety margin, when at high speeds..
So, that's my experience with drum and disc brakes. I have a very poor opinion of drum brakes.............disc brakes just work so much better, self adjusting, they don't fade, and they're easy to service.