Mechanical Vs Hydraulic Disc Brakes

Although we have covered disc brakes VS rim brakes on our blog before, we have not covered the differences between mechanical and hydraulic disc brakes. This post is especially relevant as the entire cycling industry, especially mountain bike industry has switched to supplying disc brakes on their entire bike range, so much so that even entry level mountain bikes are now fitted with disc brakes as standard.

Although disc brakes are now found across all bikes, from full suspension mountain bikes to gravel bikes and road bikes, there are a few variations in what is fitted to bikes. Although there are different size disc brakes and different disc brake manufacturers, the biggest variation in disc brakes is between hydraulic disc brakes and mechanical disc brakes.

What Are Disc Brakes?

Disc Brakes, as mentioned above have largely replaced rim brakes - they operate by applying force from the brake lever, to the disc which is mounted to a hub. Rim brakes operate by the brake force being applied directly to the rim of the wheel, via brake pads.

Hydraulic and Mechanical Disc Brakes vary in how braking force is transferred from the brake lever to the brake rotor. We cover the two types of disc brakes below:

Mechanical And Hydraulic Disc Brake Similarities

Mechanical and Hydraulic Disc Brakes both operate by the braking force from a brake lever, which in turn push the brake pads onto the disc brake rotor - which slows the bike.

Mechnical Disc Brakes Explained

Mechanical disc brakes use a steel cable which connects the brake lever, ot the brake caliper of the bike. This should be familiar to most cyclists, as it’s the same operation on rim brakes and cantilever brakes. Most modern bikes, especially premium bikes now have internal cable routing for these steel cables - which can make maintenance more complex.

Hydraulic Disc Brakes Explained

Hydraulic disc brakes work using a sealed fluid system, which transfers force from the brake lever to the brake disc rotor. The hydraulic braking system contains a master cylinder and a piston, with the master cylinder containing the brake fluid. When the brake is applied through the brake lever, then the piston moves within the cylinder - pushing brake fluid towards the caliper. This fluid then transfers pressure to the pistons inside the brake caliper, pushing the pads onto the rotor.

Advantages And Disadvantages

Mechanical disc brakes are cheaper than hydraulic disc brakes - this is true at a component level, and it’s also worth noting that bikes equipped with mechanical disc brakes will be cheaper than bikes which have been spec’d with hydraulic disc brakes.

Hydraulic disc brakes outperform mechanical disc brakes when it comes to braking performance. Although both types of disc brakes outperform rim brakes massively. Performance benefits of hydraulic disc brakes, is provided by increase in efficiency over mechanical brakes. Another advantage of hydraulic disc brakes is maintenance when ridden - on mechanical systems its easy for dirt and grime to collect around cables.

A downside of hydraulic disc brakes is the increased mainenance that they require - fluid driven braking systems require specialist tools, and can be a learning curve for many riders to work on. It can also be expensive to retrofit hydraulic disc brakes on a mountain bike which has mechanical disc brakes and it’s also worth noting that hydraulic disc brakes cannot operate with mechanical brake levers.