As you’ve probably gathered by now, there are two types of disc brake: hydraulic or mechanical. Mechanical brakes a cable pull system, like rim brakes just arranged in a different way, where hydraulic systems use fluid to transfer the force from lever to caliper.
The main difference between the two is efficiency. Even though mechanical disc brakes will be better than rim brakes (especially in the wet), they simply can’t match the efficiency of hydraulic systems. Mechanical disc systems have the same problems as rim systems, fundamentally cable friction or compression in the housing, which means that the force applied at the lever will be greater than the resulting force at the caliper.
When you pull the lever on a hydraulic brake, fluid contained in the master cylinder, which is housed in the lever body is pushed out into the system, which in turn pushes the fluid already in the system (because liquids are pretty much incompressible), forcing the pads together at the other end.
But that’s not the really smart part. To put it simply, the best bit is that a hydraulic system multiplies the effort put in at the lever so the actual braking force is greater than the force applied by you. This is why hydraulic brakes on bikes give such excellent performance for comparatively little effort, you get so much feel at the lever, and can modulate your braking far more effectively. In practice, the lever feels so light that you can basically brake using your little finger, and you have far more control over how much braking force you want to apply.
One other bonus of the hydraulic system is that it’s sealed. That means it should need very little maintenance once setup other than bleeding, which should need to be done infrequently enough that having to take your bike to a shop wouldn’t be prohibitive, but it can be done at home. Here’s our guide.
All things considered, if you’re making the switch to disc brakes then you really should be looking at hydraulics. It was the introduction of a hydraulic system, first by SRAM but quickly following by Shimano, which fast-forwarded the development of disc brakes on road bikes, and while more expensive, if you want to experience the full advantages of discs then a hydraulic setup is the way to go.
