Disc Brakes VS Rim Brakes On Mountain Bikes

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The debate between rim brakes and disk brakes have spanned years, if not decades. And with the recent addition of disc brakes in the competitive scene, the argument only looks to get more heated.

Brakes are obviously a core component of your bicycle. In essence, it is the first and last line of defense in case anything goes wrong.

But the simple bicycle brake has evolved to become much more than that.

Disc Brakes VS Rim Brakes On Mountain Bikes

Nowadays, brakes do not simply stop the bike but seek to boost your overall cycling performance, all the while trying to keep itself simple and user friendly. That is basically the crux of the debate between our two types of bike brakes: the Rim Brake and the Disc Brake.

Aesthetics aside, the major differences lie on how each of these brakes work and what advantages do they bring to the table for the cyclist. This can be categorized in the form of:

  • Performance: Stopping Power and Modulation
  • Ease of Use: Riding Style and Maintenance
  • Overall costs

We will be discussing these points in detail in this article, both from a general and a mountain biking perspective.

Disc Brakes VS Rim Brakes

Rim Brakes

Rim brakes have always been the stepping stone for all things bike brake and have seen its fair share of innovation over the years.

Simple yet effective, rim brakes follow an easy-to-understand mechanism to achieve braking. When the brakes levers are activated the tension is transferred through the cables down to the calipers. The calipers close the braking pads around the rim of the wheel, creating friction, and eventually stopping the bike.

Rim brake

Pros

+ Simple Structure

Even after decades of innovation and development, the core mechanisms of the rim brake has yet to see any significant changes.

It just works.

The fundamental design of the rim brake still acts as a blueprint for all other types of brakes, even the disc brake. In other words, it is easy to understand what each component of the braking system does, making it easier for users to travel to different places without having to worry about differences in mechanics that each new place might bring.

+ Easier to Repair and Maintain

Continuing on from the last point, the simple design of the rim brake gives it advantages in regards to maintenance as well. The operation and parts of the brake are basic enough to allow even the most casual of cyclists to try their hand on self-repair and maintenance.

+ Lightweight

The three main components of the rim brake are the lever, the brake line and the caliper. That’s it.

These components barely add any significant weight to your whole system, unlike the rotors on a disc braking system where the rotors themselves weigh a few pounds. Rim brakes weigh less than half of that of a disc brake.

This can be a point of consideration if you are looking to min-max weight in your cycling system.

+ More Aerodynamic

This is much more of a direct comparison against the disc brake. The rim brake is more aerodynamic thanks to the absence of the rotor that can add some amount of drag on straight tracks, as seen in many trails and cyclocross tracks.

+ Cheaper Than Disc Brakes

Another direct comparison: rim brakes are significantly cheaper than disc brakes. And I am talking about costs that are included even after purchase.

The lower price point is owed to its simplicity, low amount of parts, availability of parts and of course, easy maintenance.

Cons

Less Stopping Power

Compared to disc brakes, the rim brakes have slightly less stopping power, especially under wet conditions.

The rim brakes depend on the rim material of the wheel and cables to achieve braking, both of which cannot be adjusted on a rim brake.

Limited modulation

This is simply the control of braking pressure. This is a significant issue when it comes to mountain biking, with all its rough tracks, steep descents and sharp turns. Controlling the speed with locking up the wheels is a fundamental of all technical cycling.

Rim brakes simply can’t achieve the same amount of response required when compared to disc brakes.

Can wear out the Wheels

The braking pads of the rim brakes go directly on the rim of the wheels, meaning all the friction that is generated by braking is felt by the wheels themselves.

Initially it may not be significant, but over longer and frequent periods of braking (which is a given in mountain biking) can see you having to replace your wheels entirely which can significantly add to costs.

Limited Wheel Sizes

In a rim braking system the wheel is wrapped around by the calipers. And as you might have guessed, the calipers have a fixed size, meaning that your wheels cannot be wider than what your calipers can accommodate. This significantly limits the sizes of wheels that you can use on a bike with a rim brake.

Disc Brakes

The disc brake is a fairly new addition to the bike brake scene, bringing with it a new dimension of braking technology.

In terms of both form and function, disc brakes are naturally catered for the muddy and treacherous tracks of mountain biking.

Disc brakes have the advantage of having its main component, the rotor, separate from the wheel rim. This not only frees up the wheel itself, but also allows manufacturers to work on the rotors to improve performance without even touching the wheel.

Disc brake

That said, the disc brake works similarly to the rim brake with the added core component: the rotor. When the brake lever is pulled, the tension is transferred via the cable and on to the calipers that pull the brake pads together. Instead of the rims, the brake pads squeeze on the rotor installed around the hub of the wheel to achieve braking.

What we have just talked about is the mechanical disc brake. We have another type: the hydraulic disc brake. Here, instead of cables, the tension is transferred much more efficiently through the fluid housed inside the brake line. In terms of performance, the hydraulic brake is head and shoulders above its mechanical counterpart, not to say anything about rim brakes.

Pros

+ More Power

These brakes are specifically designed for performance and do not rely on the quality of the rim surface. Meaning that they offer more power solely depending on the rotors (more on that later).

+ Better Modulation

A more precise and smoother braking is possible with disc brakes. The cyclist can easily gauge the amount of power required to brake, even more so on the hydraulic ones. This gives a better sense of control, which is integral in any descent.

+ You can adjust your braking power by changing rotor sizes

The rotor comes in many different sizes. You can adjust your braking power and modulation just by changing them

+ Weather Resistant

Disc brakes are impervious to wet and muddy conditions.

The rotors are smaller than the wheel rims and water is easily brushed off by the calipers.

Being separate from the wheels, the rotors can be designed to have mud shedding properties.

+ Heat Dissipation

Being separate from the wheels also allows all the heat produced by braking to stay within the rotor.

Manufacturers are now experimenting with materials and design to make the rotors dissipate heat more efficiently.

+ Does not wear down the tire

All the friction that is produced by braking is experienced by the rotor. The wheel is kept intact.

It is much cheaper to replace the rotor than to do the same for the wheel in case it wears out.

+ Tire Clearance

The size of tires you use does not matter. As the calipers are wrapped around the rotor, you are free to use any size of wheel on your bike.

This makes disc brakes ideal for fat tires and e-bikes too.

Cons

Weight
The rotor happens to be a double edged sword in this regard. It adds a pond or more to the overall system.

While it may not be a significant amount, the added weight will add up and be felt on steep climbs.

It also goes without saying that the larger the rotor the heavier it will be.

Maintenance

With more parts, maintenance and repair can prove to be difficult. Especially for the hydraulic disc brake with its closed system.

Expensive

The more complicated maintenance coupled with the rarer parts (the disc brake is still fairly new to the market) can ramp up costs. Not to mention the ‘bleeding’ that is involved with hydraulic disc brakes can put a hole in your pocket, if you let a bike shop do it for you.

Frequently Asked Questions

Q1) Can I change rim brakes to disc brakes?

Ans.: No, not completely anyway. Rim and disc brakes usually have completely different mount types, but with some modern rim brakes it is possible to convert the ‘keeper’ standard rim brake to a hybrid.

In that case, you have to consider certain points:

  • Will the new fork function with your frame?
  • The type of disc brake you want to use: Mechanical or Hydraulic?
  • Are the wheels disc brake compatible?
  • What kind of rotor will you use?

We suggest you should only do this if you have a limited budget which is stopping you from migrating completely.

Q2) Are disc brakes worth the extra weight?

Ans.: Yes. On the surface level, rim brakes do not differ much in terms of performance against disc brakes. But each of them have their own advantages under certain conditions.

The conditions where the added weight of the disc brake is justified are:

  • You are looking for more control around corners.
  • You usually ride under wet conditions.
  • Your riding focuses on descent.
  • You are already a heavy set person.

Final Words

Understand that there are a plethora of other variables involved, even if we narrow our cycling environment down to just mountain biking. It is really up to the cyclist to weigh the pros and cons against each other to determine the best for themselves.

That said, hopefully we were able to bring out all the features of both the rim and disc brake to a better light for you to understand them better. And also to determine a stance for yourself in this long debate.

Happy Riding!

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My name is Dion Lewis. I’ve been cycling since my childhood. When I was in high school, I started racing in our local competitions. In my college life, I took a part-time job in a bicycle shop and I learned how to repair and maintain bicycles professionally. Though I love racing, mountain biking is another thing I do frequently. My friends, neighbors, and colleagues treat me as an avid rider and take my suggestions while they plan for a new bike or bike gear.

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