IANAM, but after studying cutaway drawings of both drum and disc brakes, the latter seems like it would be much less complicated and expensive. One reason might be because disc brakes are usually accompanied by costly hydraulic systems, while drum brakes are unassisted. Is there such thing as an unassisted disc brake? Another reason might be that disc brakes require a greater attention and costly, warp-resistant alloys in production.
Yeah, I think it’s those damned expensive rotors. Not your ordinary melted-down bowling trophies, I wager. They’re designed to withstand crushing rotational pressures – but, I’ve read, are very vulnerable to side impact damage. Try to replace one on a motorcycle and it could set you back hundreds of bucks.
Same for mountain bikes, but well worth it. Nothing can even come close to the stopping power, except for maybe a parked car. :eek:
Disc brakes probably need to be hydraulic in order
to work. I can’t think of any other way you could
generate sufficient clamping force reliably.
A lever system would fatigue and break, if it didn’t
melt straight down from the intense heat. It would also
make the pedal travel a lot farther when the pads
were worn down.
Other than that, cost of materials (because of
the heat factor) and the necessity of precision
machining those very tough materials.
-Ben