We had those in the early 80s, they sucked. That is why we heve the gyro.
BTW, it's called a rotor.
Do you understand that in the 80s, there were no hydraulic brakes.. And it's not called a rotor.. It's the hydro gyro..
hahaha, there was hydraulic brakes in the 80's and i have proof. in caps bycicles in richmond they have a really old down hill(1986) with origanal hydro brakes.