Your brakes are one of the most important parts of your bike: they keep you safe! But which is a better braking system, disc brakes vs rim brakes?
In recent years, the best type of braking system for your bike has been hotly debated amongst roadies, and there are benefits and drawbacks to both rim and disc brakes.
However, the divisiveness of the debate can make it difficult to find objective information about their strengths and weaknesses that aren’t informed by opinion.
So, how do disc brakes and rim brakes work? And what are the strengths and weaknesses of each braking system?
Don’t worry! In this article, we’re going to explain how the two braking systems work, as well as their comparative strengths and weaknesses. To get you up to speed, we’ll be covering:
- Disc Brakes: How Do They Work?
- Rim Brakes: How Do They Work?
- Advantages Of Disc Brakes
- Advantages Of Rim Brakes
- Disc Brakes Vs Rim Brakes: Which Should You Choose?
Ready for the hotly debated showdown: disc brakes vs rim brakes?
Let’s get started!
Disc brakes: How Do they work?
Disc brakes have been one of the new additions to the road cycling world in the last decade.
Initially invented by Shimano in 1971 as an adaptation of the motor industry standard braking system; interestingly, disc brakes were initially released for road bikes.
However, due to the added weight of a disc brake system, they were quickly shunned by the road cycling world and never really took off.
In the late ’80s, as Shimano began getting a foothold in the MTB world, they thought back to their invention from over a decade prior and re-adapted the system for mountain bikes, where it found its rightful home.
However, it wasn’t until the 2010s that disc brakes made their long-awaited comeback to road cycling.
After a lot of indecision over whether they should be allowed, they were eventually approved by the UCI for use in professional road cycling and have become by far the most common braking system in the pro peloton.
So, at some point or another, disc brakes have been accepted into nearly every cycling discipline. But how do they work?
Disc brakes are made up of three main parts: the calipers, the levers, and the rotors.
In essence, all disc brakes work the same: pulling on the lever actuates the pistons inside the caliper, which clamps onto the rotor, generating friction to slow the wheel.
However, there is variation in how these parts are linked; and the mechanism through which the levers actuate the pistons. Generally, there are two different disc brake systems: mechanical and hydraulic.
Mechanical disc brakes are cable actuated. This means that the lever and caliper are connected by a taught cable which, when the lever is pulled, applies tension across the caliper and forces the pistons to close onto the rotor.
Hydraulic disc brakes are hydraulically actuated. This means that the lever and the caliper are connected by a “hose” filled to the brim with braking fluid.
When the lever is pulled, a small amount of fluid is displaced, forcing the whole fluid column downwards and applying a force on the pistons, which then close onto the rotor.
- Want to know more? Check out our article Mechanical Vs Hydraulic Disc Brakes: Everything You Need To Know!
Rim Brakes: How do they work?
Rim brakes have been the road bike industry’s standard braking system arguably since the inception of the discipline.
Needing no introduction, they are still found on the majority of road bikes, hybrids, and town bikes you’re likely to see on the street.
Rim brakes are made up of two main parts: the calipers and the levers. They don’t need a rotor because the pads act on the rims, which are already a part of your wheels.
Rim brakes work similarly to mechanical disc brakes: the levers are attached to the calipers by a taught cable which, when the lever is pulled, applies a tension across the caliper, forcing the “brake shoes” together and generating friction on the wheel’s rim.
The brake shoes are attached to the caliper on either side of the rim, with a small amount of spacing between them and the rim itself. These two shoes are attached by a hinge which, when tension is applied across the caliper, allows one to move freely towards the other.
Advantages of disc brakes
Disc brakes rapidly became the peloton favorite over the past decade, but why is that?
When comparing rim brakes vs disc brakes, usually the biggest advantage offered by disc brakes is their vastly superior braking power. This is true for mechanical and hydraulic disc brakes, but hydraulic disc brakes are considerably more powerful.
Additionally, hydraulic disc brakes afford the rider greater control over the braking force with enhanced modulation. Modulation refers to the ability to control the braking power by squeezing the brake levers to a different degree.
One of the biggest advantages of disc brakes is that their braking power is far more reliable in different weather conditions. In the rain, rim brakes often suffer from decreased braking power due to lubrication between the pads and the rims.
However, the material of the brake pads in the disc brake calipers and the fact that they are better sheltered from the rain means that they don’t usually decrease in quality during a rainstorm.
Since the disc brake’s design is better at keeping contaminants away, the braking surface of the pads tends to last much longer than that of rim brakes. Additionally, replacing just the pad is much cheaper than replacing a worn-out rim or wheel.
Advantages of rim brakes
Although disc brakes are becoming the favored choice for many, rim brakes retain many loyal users for several reasons.
Perhaps the best reason to stick with the rim brakes is that your bike is only compatible with them.
If you’ve already got rim brakes, you’ll have to trade out both your frame and forks for ones with the correct mounting points for disc brake calipers if you want disc brakes.
This is extremely expensive, and you cannot safely fit disc brakes to a rim brake bike.
Additionally, although rim brakes wear out more easily, they’re a lot simpler in design when compared to hydraulic disc brakes. In the event of a fault, fixing a cable-actuated brake, in general, is much easier and less messy than fixing hydraulic brakes.
This simpler design also means that less can go wrong. Owners of disc brakes know just how fiddly they can be. Fixing a squeal or rub on a disc brake can be a nightmare due to the multitude of causes, including alignment, contamination, and a bent rotor.
Rim brakes, on the other hand, are much easier to realign, can be loosened with the lever on the side, and are much less likely to have a problem with alignment in the first place.
Rim brakes may be susceptible to decreased effectiveness in the rain, but if you get contaminants on the pads or rims, then it won’t affect the long-term performance.
If you accidentally contaminate your disc brakes (mud, degreaser, lube), then they will be permanently affected by this, and you’ll need to replace the pads and sometimes even the rotors.
Although the braking surfaces wear out more frequently, it’s a lot easier to check that they have. To the untrained eye, it can be nearly impossible to tell if your disc brake pads are worn without removing them (a fiddly job).
With rim brakes, you can see when your rubber pads or rim are worn out just by looking at them, even when cycling. The pads have lines that mark the minimum thickness for them to remain effective, and the rims will go concave when they need replacing.
And there’s one other key advantage of rim brakes vs disc brakes: weight.
Though many within the pro peloton have clearly decided the performance benefits of disc brakes justify the weight penalty, for hill-climb specialists or lightweight obsessives it’s a consideration worth bearing in mind.
With the weight of the rotors and a fluid-filled hose, a disc-brake-equipped bike can be as much as 500 grams heavier than the rim-brake equivalent.
Disc Brakes Vs Rim Brakes: Which Should You Choose?
Like most subjective questions like this one, it really depends on your riding style and discipline.
Firstly, if you’re an off-road cyclist using a cyclocross, gravel, or mountain bike, then disc brakes are definitely the best choice. The enhanced modulation, braking power, and protection against contamination make them far more suited to off-road disciplines.
The answer is much less black-and-white if you’re on a road or hybrid bike.
The first question you should answer is whether you already have rim or disc brakes. Either way, you’d have to buy a whole new frame and fork to switch to the other – an expensive ordeal. It’s likely not worth spending all that money to switch your braking system.
If you’re buying a new bike anyway, then it depends on your budget.
For most riders, the advantages of disc brakes (modulation, braking power, resistance to weather conditions, lack of contamination) outweigh the benefits of rim brakes (simpler design, less fiddly). Then, it comes down to budget.
Disc brakes only tend to come with mid-upper range groupsets and above, so these bikes will generally cost more money.
Overall, it’s impossible to give one answer to this question. But, if you’ve got an unlimited budget and you’re buying a new bike, then comparing disc brakes vs rim brakes: which is a more powerful and reliable braking system?
With all else equal, hydraulic disc brakes offer the best braking power, modulation, and resistance to weather conditions of any braking system, which will be the most important factors for many.
