Early machines were slow and had very poor brakes, sometimes only on the rear, and some had rim brakes like bicycles, which were also used on some lightweight race bikes.
The introduction of drum brakes was a significant step forward, but they were still poor – particularly front drum brakes with single leading brake shoes, bearing in mind at least 60% of braking is done by the front, and up to 100% as the weight transfers forwards.
Aftermarket twin leading shoes became available – John Tickle – and four leading from Fontana. Even 8 leading shoe were used on racers.
The rear brake was key, as the leverage was far higher with the rider standing on the pedal.
The front brake was wholly dependent on how strong your grip was, and lock ups probably very rare.
In the 1970s disc brakes started to appear which were initially poor in the wet, but over the years friction materials, master and slave cylinder designs have improved.
I cannot remember ever locking a front brake on tarmac until 1992, and that was on a race bike with twin AP Lockheed race calipers and cold tyres.
The latest radial brakes are very powerful, requiring only one or two fingers to stand a machine on its nose, or a lock up.
ABS has been around since the 1970s, but was mainly fitted on top end touring bikes until 2016 when they became compulsory for all bikes over 125cc.
There is a now a particular problem with machines from around 2000 onwards which have increasingly powerful brakes capable of locking the front wheel with just one or two fingers, which is probably a significant factor with riders falling in an emergency.
As many riders have more than one bike, there is a real danger of going back to earlier machines without ABS (or traction control, anti tipping or anti wheelie) and skidding and falling.
British Superbike School 