What are the disadvantages of hydraulic brakes

Brake systems on bicycles: overview and useful information

One thing is certain: the brakes are of crucial importance on bicycles.
Of course, safety plays the most important role: it is not for nothing that two independently functioning brakes are required for a roadworthy bicycle.
In addition, the brake should match the other components as well as the bike itself.

Here you can learn a lot about the different braking systems for bicycles.

Despite the proliferation of disc brakes, rim brakes are still widely used. This braking system continues to enjoy great popularity.
A basic distinction must be made between hydraulic and mechanical rim brakes.

Hydraulic vs. mechanical rim brakes

In addition to the classic mechanical rim brakes such as the V-rim brakes (V-brakes) and the cantilever brakes, more and more hydraulic brake systems are emerging. Both types have their justification, with hydraulic rim brakes serving a more expensive segment.

Mechanical rim brakes have the following properties:

  • There is a type of brake on both sides of the wheel
  • The type of braking is operated with the help of a cable (therefore also cable brake)
  • With the cantilever brakes, which are rarely installed today, a transverse pull pulls the brakes together
  • With V-brakes, the arms are connected by a brake cable that runs through a guide tube and a bellows

With hydraulic rim brakes, the functionality differs slightly from this:

  • The brake pads are adjusted hydraulically, which increases the braking force
  • A fluid in the brake hose regulates the strength of the deceleration, which results in less friction
  • A fine dosage of the braking effect is possible, as this is less delayed than with mechanical systems
  • Since hydraulic rim brakes form a virtually closed system, hardly any water and dirt penetrate

Hydraulic rim brakes develop a stronger and therefore safer braking effect than mechanical ones. In addition, you do not have to replace the cables on them regularly. Instead, it is important here to change the brake fluid at some time intervals.

Advantages and disadvantages of the rim brake

Compared to disc brakes, rim brakes have some advantages and disadvantages.

advantages

  • The lining wear is less
  • They are lighter in weight
  • The price performance ratio is very good
  • The assembly is relatively easy

disadvantage

  • The braking force is less than with disc brakes
  • The braking effect quickly diminishes in wet conditions
  • The rims threaten to get hot on descents
  • The brake pads need to be changed more often
  • More effort is required when braking

This type of brake is clearly on the rise. (Hydraulic) disc brakes are almost standard on mountain bikes. However, this system is enjoying increasing popularity, for example, on a large number of e-bikes, trekking bikes and racing bikes.
After all, disc brakes provide a snappy deceleration force in all conditions.

Mechanical vs. hydraulic disc brake

As is the case with rim brakes, both mechanical and hydraulic variants are used for disc brakes. Hydraulic disc brakes are very popular because of their precise, direct reaction, with mechanical disc brakes being cheaper and less technically complex.

In the following, the functionality and the special features of mechanical and hydraulic disc brakes are presented in a brief, concise overview:

  • Mechanical disc brakes work via a Bowden cable (similar to mechanical rim brakes)
  • Hydraulic disc brakes, on the other hand, are operated with brake fluid
  • Due to the tensile friction, mechanical disc brakes are not as direct and precise as hydraulic ones
  • Mechanical disc brakes mostly have only one piston, while hydraulic ones have two or four pistons
  • You have to bleed hydraulic disc brakes regularly, but they are very reliable
  • Mechanical disc brakes require less maintenance, but are more prone to dirt and rust

In terms of braking force, hydraulic brakes are therefore superior to mechanical variants. For this reason, there is virtually no getting around them with mountain bikes. Mechanical disc brakes, on the other hand, pay more off for cheaper bikes that do not require too complex technology.

As a type of brake, disc brakes are rightly used more and more frequently. Their strong braking force in all conditions is the decisive argument in favor of the system with a brake disc. But of course there are both advantages and disadvantages here as well.

advantages

  • A high performance in all conditions (even in wet conditions)
  • greater tire clearance than with rim brakes
  • You only need a little hand force to achieve high braking performance
  • The rims do not overheat on longer, steeper descents
  • The pads have to be changed less often than with rim brakes
  • The brake discs are less prone to dirt

disadvantage

  • Due to the higher technical effort, disc brakes cost more than rim brakes
  • Disc brakes are heavier than rim brakes
  • On long descents, the brake discs instead of the rims can get too hot
  • The spokes and the hubs are under higher loads
  • Disc brakes have to be braked first

Anti-lock braking systems (ABS) found their way into cars a long time ago and are now an integral part of motorcycles as well. If more and more electronics are being added to bicycles, ABS as a driving aid is only a logical consequence.

Building on its pioneering position in the motorcycle sector, Bosch developed the first ABS that went into series production for bicycles. Objective: The ABS is intended to prevent the front wheel from locking and thus the impending exit via the handlebars. The same goal is pursued by a lift control on the rear wheel, which is also used. In addition, slipping should be avoided in wet conditions or on loose surfaces.

The system works in the following way:

  • A speed sensor determines whether the front wheel is about to lock
  • If a blockage is detected, the system automatically reduces the brake pressure
  • Just like the ABS, the lift control should also increase driving stability
  • The lift-off regulation controls an impending lift-off of the rear wheel
  • If an imminent lift is detected, the system also lowers the brake pressure on the front wheel

The anti-lock braking system from Bosch prevents falls, especially for inexperienced and unsafe drivers, and thus makes a major contribution to safety. It is mainly used on trekking and city bikes. On asphalt and loose ground, it reliably helps out of dangerous situations and can efficiently prevent rollovers. Even when the system intervenes, the e-bike remains easy to control.

For the E-MTB, on the other hand, it makes less sense, as the braking distance becomes longer due to the reduction in the deceleration effect. The system has its limits in the event of sudden obstacles and adverse conditions. In order to reliably avoid falls here too, it would have to intervene in even more differentiated ways.

Exciting alternative: The ABS from Blubrake

The Italian company Blubrake has developed an anti-lock braking system for e-bikes that is fully integrated into the frame, making it a real innovation. This system is already used in some Bulls models.

Since the control unit in the Bosch system hangs somewhat unattractively and clumsily from the handlebar, integrating the ABS into the top tube has many visual advantages. In addition, the Blubrake ABS is compatible with all hydraulic brakes and electrical systems on the bicycle market. It can be integrated into the frame of any e-bike, from trekking bikes to MTBs.

The system works in the following way:

  • The movement and dynamics of the bike are controlled by the rotation sensor of the control unit
  • The system automatically recognizes dangers that can occur when the vehicle is slowed down too quickly
  • In such a case, the ABS reduces the hydraulic pressure of the front brake

All in all, the Blubrake ABS consists of a drive that is connected to the braking system of the e-bike, a control unit connected to the battery, a speed sensor and an information display.

With its full integration into the e-bike frame, Blubrake is a powerful competitor to the Bosch system. Bosch has to counter this with its outstanding market position. On the other hand, the Blubrake system convinces with its compatibility with all hydraulic brakes and with its suitability for E-MTBs and E-cargo bikes.

However, with some e-bikes it could be a challenge to integrate the system into the frame. This task is incumbent on the manufacturers, for whom Bulls is playing a pioneering role with the Blubrake system.

The assembly of a bicycle brake can quickly become a problem. In any case, make sure that the right mounts for the brakes are on the bike. After all, these differ significantly for rim and disc brakes.

Among other things, the following things should be observed when assembling the wheels:

  • Since both rim and disc brakes need the right rim or hub, you should take a close look at your wheels before buying the brakes
  • With a rim brake, the rim requires a braking surface (bare metal surface on the outside without paint)
  • In the case of a disc brake, the spoked hub must have a receptacle, either a 6-hole hub or a centerlock hub, for the brake disc
  • With a 6-hole hub, the brake disc is fastened with six screws, with a Centerlock hub, on the other hand, with a locking ring

When mounting on the fork and on the frame, the following things are important:

  • Cantilever and V-brakes require a suitable socket (Centilever socket) on the seat stays or on the fork tubes. The brakes are put on two threaded sleeves and screwed tight
  • Side-pull brakes are attached to the fork crown with a screw
  • Disc brakes have three different standards: Post Mount, Flat Mount and IS2000
  • With the IS2000 standard, the brake calliper is fixed from the side with vertical screws
  • With the post mount and flat mount standard, on the other hand, the brake calliper is fixed from above or below