A change of technical components, but there’s more. A change of trend, style, safety and habits. Rim brakes vs disc brakes, who wins? Impossible to say, as there are always different schools of thought and different philosophies. Both types of brakes have their advantages and disadvantages, performance differences in specific situations, as well as different maintenance requirements. Let's discover the most important differences and the pros and cons.
The truth is not in the middle
All cycling enthusiasts remember rim brakes in all the first races they watched on TV, no matter when they were. These are the classic brakes that have always been installed on bikes and that all of us probably learned about as children. Conversely, disc brakes represented for everyone, including professionals, not only a great technological innovation but also something to get used to, both visually and in use. While for some this innovation guarantees increased safety when braking, many are still using rim brakes as they are a guarantee and a habit that they don’t want to change, and at the same time they consider disc brakes as a novelty that they can do without. Where is the truth? Is it, as it often happens, in the middle? Actually, in this case it would be simplistic to say so. Indeed, important data shows that innovation may have greatly improved the situation for cyclists, both amateurs and professionals. Let’s investigate this further.
The rim brakes of racing bikes are the parts that work in contact with the rim, activated by the brake calipers. These components are made of soft, rubbery material guaranteeing maximum possible friction. The rubber of the skates is very high in density and is made so as not to deteriorate too quickly when subjected to the high temperatures created by kinetic energy during braking. The rubber parts have grooves for water drainage and for easy removal of the dirt that can settle there. The direction of these grooves is very important for the correct installation of the brakes which, if installed in reverse, do not work as they should, or could even come out of their site. This detail already lets us understand that the assembly of the pads is an operation which shouldn’t be taken for granted and must be done by expert hands. Brakes are no walk in the park. So, if you have even the slightest doubt about how to do it when changing the brake pads on your road bike, contact a bicycle mechanic who will do the job professionally. Now, let's see how they work in the two main phases, the activation and the distribution of the braking:
- Braking activation: this occurs through a metal cable subjected to tension and, therefore, subject to loosening over time.
- Braking distribution: the contact point is the braking track of the rim which is squeezed between the two pads and therefore slows down the bike.
What are the advantages of rim brakes?
- Without a doubt, rim brakes have a much lower purchase and maintenance cost compared to disc brakes.
- Weight matters, especially for professionals, and rim brakes guarantee a much lower weight than disc brakes.
- Less inertia, due to the absence of the disc.
- At present, it is much easier to find brakes, frames and wheels compatible with rim brakes.
What are the disadvantages?
- In case of long and frequent braking, as can happen on very steep descents, the pads can overheat and lose modularity and efficiency.
- Similarly, rim brakes may be less efficient in the rain, as water alters their adherence on the rim.
- The effort that a cyclist must exert to brake is more intense than what is required when using disc brakes.
It is a fact that more and more professionals are choosing to use disc brakes over rim brakes. This is a revolution that is quickly taking over and still finds many skeptics, but which will most likely be complete in a few years’ time. Many technical steps forward have been made, and soon all the difficulties of disc brakes may no longer exist. Compared to traditional brakes, how do disc brakes work? Again, let’s analyze braking activation and distribution.
- Braking activation: the system consists of the pumping element (paired with the lever), the hydraulic circuit and the caliper. The operating principle consists in putting an incompressible fluid under pressure and transferring the force applied to the lever onto the brake pads.
- Braking distribution: the force applied to the pads compresses the disc along with the hub, slowing down rotation.
What are the advantages of disc brakes?
- The disc brake offers more braking power than traditional brakes, allowing for better slowdown at high speeds.
- Less force applied to the lever for the same deceleration
- Greater modularity. Braking is more controllable and fluid
- On wet asphalt they guarantee better grip: disc brakes significantly reduce the risk of losing control and make braking less difficult.
What are the disadvantages?
- Disc brakes are more expensive than traditional ones
- Frame and wheels: you cannot switch from traditional brakes to disc brakes on an old road bike, as disc brakes require special wheels and frames.
- Weight: as always it is an important variable, which can make a difference for competitive racers. Disc brakes weigh more than rim brakes (although disc brakes are being made increasingly lighter).
- Greater inertia, due to the presence of the disc.
Speed or difficulty changing the wheel?
We have not included this aspect among the advantages nor among the disadvantages, as there are still several schools of thought regarding this specific situation, that is, the moment when the wheels are being changed. This is a circumstance that mainly affects professionals since, in the event of a flat, the moment of wheel change during a race is often crucial and saving even just a few seconds can make a difference.
Changing a wheel with a disc brake requires a lot of care, as the rotor must be installed in its place and in most cases, especially in a race, this operation is not minor. In recent years, in fact, more and more professional teams have been simply switching bikes in the event of a flat, thus avoiding this problem.
In favor of the disc, however, it’s important to mention that this configuration is always accompanied by a thru axle coupling system and no longer with the classic quick release (the system in use with rim brakes). The wheel can be fixed onto the frame by simply screwing in the thru axle, which for racing bikes is 12 mm in diameter, simplifying the operations of removal and installation.
Another very important aspect of this configuration is that the introduction of the thru axle system has led to a significant increase in rigidity, along with a significantly reduced weight. This rigidity gives the rider more feeling while braking, for the benefit of performance and safety.
As always, we are not here to give definitive answers (also because there aren’t any), but to critically evaluate options with you. There is no denying that disc brakes are the future, and for many they are already the present, especially in the professional world. In an area where performance level is everything, it is clear that the choice should be the safest and highest performing solution. However, it is reasonable to think that rim brakes will never disappear. There is a world of amateur cyclists, as well as competitive riders, who will continue to prefer classic brakes for various reasons, such as cost, maintenance or simply due to habit. Therefore, these two types of brakes will most likely coexist over time, giving each other some healthy competition, just like two bikers in a race.