Advantages of hydraulic disk brakes over mechanical ones?

With the rapid and often bewildering advances in cycling technology, it’s hard to decide whether the mechanical braking system you already have fitted to your bike should be upgraded or whether it will suit your purposes and your riding style just fine. We did some research and this is what we found out:

Hydraulic brakes are smoother to operate, more responsive, and require much less brake-lever force to bring you to a stop, so they are more efficient than cables because they rely on an incompressible fluid that isn’t affected by mud and weather conditions.

Before we start waxing lyrical, we should first understand the difference between the two technologies and, indeed, how a braking system work in the first place. We’ve put together a comprehensive comparison between the two types.

How Do Brakes Work?

So how do braking systems work in the first place?

As a rider, whether you’re scything down the tarmac on your road bike or you’re carving up the single track on your MTB, your forward momentum is known as kinetic energy. To bring that substantial force to a halt your brake system must dissipate the energy you’ve created and it does that by converting kinetic energy into thermal energy through friction.

In other words, your braking system is a friction generator. When you wish to stop or slow your impetus, you will pull on your brake lever. This will drive either a mechanical cable or a hydraulic arrangement to actuate a brake pad that will make contact with the braking surface of your bicycle.

The more pressure you apply to the braking surface through the brake lever, the more the stopping power.

These braking surfaces can be located either on the rim of your wheel or the surface of a rotating disc. The rim brake type will use replaceable rubber pads mounted in a brake shoe to dissipate the heat against the wheel.

The disc brake pad is made from a variety of composite materials selected for durability and heat resistance, and they are mounted within a caliper through which the disc, or rotor, runs.

Although this is not a discussion about the merits of the rim brake over the hydraulic brake, it should be noted that most mountain bikes sold these days are fitted with disc brakes and, until very recently, most road bikes were fitted with mechanical rim brakes.

Indeed, no less a luminary in the world of cycling than the four-time Tour de France winner, Chris Froome, is a firm advocate of rim brakes. It seems though, that the world of cycling is moving towards the disc brake as the standard.

What Is the Difference?

There are many more advantages to the hydraulic system and one or two disadvantages. There is a good reason why no serious mountain biker would be seen out in public with a mechanical brake system, and they’re good reasons why a road cyclist might go with a mechanical setup.

Hydraulic systems:

These are a closed system of hoses, calipers, and reservoirs containing a specific hydraulic fluid to work the brakes. When you pull on the brake lever, a small piston within the lever body will transfer that force through a hose filled with hydraulic brake fluid to the brake caliper.

This in turn acts on the pistons in the brake caliper to engage the brake pads onto the rotating disc. The greater force applied to the lever will result in greater pressure being applied to the braking surface.

The hydraulic braking fluid used in these brake systems is either DOT fluid or mineral oil. Both are perfect for this application due to their incompressibility, which negates a spongy brake feel.

DOT fluid gets its name from the US Department of Transport, which regulates the quality and the attributes of the fluid.

Mechanical systems:

This is a much simpler system. Mechanical brakes are cable-actuated in that they use a cable attached to the brake levers to activate the braking system. When you pull on the brake lever, the cable is drawn inward to the brake lever housing.

This tension will actuate the brake system, whether it is a disc or rim brake setup, to present the brake pad to the rim of the rotor. As with hydraulic brake systems, the harder you pull, the greater the force applied to the braking surface.

The cable consists of a braided stainless steel wire and a protective outer cable housing.

Advantages of the Hydraulic System of Braking

Performance

One would imagine that it is unnecessary to point out that the most important aspect of forwarding momentum is the ability to control that forward momentum. In other words, it’s more important that your motion is brought to a standstill by your brakes than by a tree, or the tarmac.

Both types of brakes will be able to do this but the capacity for much greater control is where hydraulic brakes come into their own.

The sponginess you will sometimes feel through the brake levers of a mechanical, cable-operated system due to the stretching of the braided wire is entirely negated by the incompressibility of the fluid within the lines of the hydraulic system.

Hydraulic brakes are smoother to operate and more responsive and require much less brake-lever force to bring your progress to a halt.

Maintenance

As mentioned, the hydraulic setup is a closed system. The advantage of this is that the inevitable dirt and debris buildup around the calipers, the pads, and the brake lines cannot enter the system and maintenance is, therefore, an extremely occasional exercise.

Mechanical brakes on the other hand will need to be maintained on a fairly regular basis if they are to provide a trustworthy shopping experience. Because they have an open design, they tend to allow the ingress of grit and debris, which will clog the hoses within a few hundred miles of riding.

This results in less smooth braking and will therefore reduce your ability to control the speed of your bike.

Weight

The one thing we do know about many cyclists is that they are serious weight-weenies and although the advantage is slight, the hydraulic system is the better of the two options. The brake lever housing, the hoses, and the calipers are all somewhat lighter than their mechanical equivalents.

Advantages of the Mechanical Braking System

Cost

In general, a mechanical system of equivalent quality will be significantly less expensive than its more sophisticated hydraulic counterpart. The parts are also relatively inexpensive and, because they’ve been around for generations, they are easily obtainable from any bike shop.

Design

They are a pretty simple design that has been around for decades. As such they are very easy to work with and to use, even for the beginner cyclist.

There is little to no learning curve as well which, for the cyclist who just wants to buy a bike and ride it, and not worry too much about how the thing works, is a great incentive to opt for this style of the braking system.

Disadvantages of the Hydraulic System of Braking

Maintenance and Adjustment

I know we mentioned maintenance (or the lack of it) as an advantage to hydraulic brakes, but you should know that when the time does come to maintain or repair the system it is not a task for anyone other than a person well-versed in cleaning and adjusting the closed system.

Just bleeding the hoses to ensure there is no air in the lines will test your patience and have you frantically googling the contact details of the nearest bike mechanic.

Cost

They’re also significantly more pricy, so if you’re a beginner or on a fairly tight budget, then you may want to reconsider the hydraulic system. Mechanical brakes will, if maintained properly, stop your bicycle just as effectively and efficiently as hydraulic ones.

Disadvantages of the Mechanical System of Braking

Weight

They’re heavier than hydraulic brakes so if you’re a weight-weenie (and most cyclists are) you should go for the lighter option.

Performance

They require more pressure on the liver to produce the same stopping power as the hydraulic variety and they’re not quite as responsive, especially if they are not regularly maintained.

Maintenance

They require it. A lot more than the hydraulic system does. So if you have the time and the patience, or you just love tinkering around your bike then this is a serious consideration.

So Which System Is for You?

It’s important to remember that hydraulic and mechanical braking systems do, essentially, the same thing. They will both halt the forward motion of you and your bike.

The system you choose to set up on your bike depends on several factors such as how much cycling you are planning on doing. Where you will be riding and what sort of terrain you think you’re likely to be riding through. Your budget, etcetera.

However, if you’re into intricate trail riding, or blasting along technical single-track at high speed, then the hydraulic braking system is a must.

If, on the other hand, you are a commuter or just a weekend warrior who wants to take in the fresh air now and then, and you’re on a budget, then the mechanical braking system is a great choice.