
Disc brakes vs rim brakes: which one is better?
When buying a bike, a lot of people may be inclined to only consider the go, go, go aspect. Except if all your bike could do was go, you'd find yourself going through quite a lot of things.
Having a reliable set of brakes on your bike not only enables you to stop/reduce speed safely but can improve the flow of your ride and improve performance.
The two main categories of bike brakes are rim brakes and disc brakes. Within these two types, there are individual categories that boast advantages when it comes to achieving the best ride. But how are they different?
In this guide, we'll compare disc brakes to conventional rim brakes to help you choose the best bike for your ride in the future.
How do brakes work?
In the United Kingdom, it is an illegal offence to ride a road-worthy bicycle without two brakes that can operate independently from one another.
All brakes are designed to apply friction to the wheel of the bicycle and bikes are fitted with a braking system at the front and back of the bike. Upon compression of the brake handle, the pressure is applied to the wheel and the increased friction will bring the bike to a stop. The difference between rim and disc brakes is where and how the braking force is applied to the wheel of a bicycle.
What are disc brakes?
Disc brakes create a very high amount of stopping power, often more than necessary to stop a standard road bike. Disc brakes are different to rim brakes as they do not clamp the rim but attach to a hub-fixed "rotor". Disc brakes also require a compatible hub, wheel rim, and frame/fork.
Even though disc brakes are heavier than conventional rim options, the cyclist doesn't need to apply as much force to the lever before the bike comes to a halt. With less effort put into the grip, muscle fatigue is decreased, especially on longer rides.
Disc brakes are considered the superior option for mountain bikes for several reasons. For one, they are completely immune to trail debris, water, and mud. When a rider careers through a river or bog deep enough to cover the rotor, the hard pads sheer the water and mud away from the motor immediately with their strength and pressure.
As rim brakes lift and then lower, they have a tendency to harbour dust, sand and mud in their soft rubber pads which can reduce braking ability and reduce speed. Also, rim brakes generate a lot of heat and, for a mountain bike descent where brakes might be used frequently, disc brakes are better because they're immune to heat.
Due to concerns about their safety (and superior performance potential), disc brakes were only validated for all international and domestic competitions in early 2018.
How do disc brakes work?
They’ve got incredible stopping power, they’re pretty good at self-cleaning and they don’t clamp around the wheel rim … so how do they work?
A disc brake system is made up of a brake disc, a brake calliper and brake pads. There are mechanical and hydraulic versions. For the hydraulic system, once the brake is applied, pressurised hydraulic fluid squeezes the brake pad friction material against the surface of the rotating brake disc.
Mechanical disc brakes share the same pad materials and rotors as hydraulic systems. The difference is that mechanical systems use a standard brake cable to activate the brake instead of hydraulic fluid.
How to tighten bike disc brakes
Over time, all brake pads and brake components can become loose. Loose or worn brake parts can lead to reduced braking ability and issues in your ride. Knowing how to tighten them can make sure you stay at the top of your performance. Our Crankbrothers M19 Multi-tool will make quick work on any adjustments.
The following points are very general, and cyclists should always refer to the manufacturer's websites for exact advice...or even better leave it to the professionals and use your local bike shop and book your bike into their workshop.
- Adjust the position of the caliper. Loosen the two bolts holding the caliper so that you can move the caliper from side to side.
- With the brake arm in the rested position, position the caliper so the moving pad is as close to the caliper as possible without rubbing. Re-tighten the caliper mounting bolts, alternating until they are both tight. Spin the wheel to make sure there is no rubbing on any point on the rotor.
- Set the position of the inside stationary pad. On the back side of the rotor, there is a nut that can be turned to move the pad in or out. Turning clockwise will move it toward the rotor, counterclockwise will move it away. Aim to have the pad further away from the rotor than the moving pad.
- Squeeze the brake lever to test the caliper. The brake should fully engage before the lever is pulled back to the handlebar. If you're able to pull the lever all the way to the handlebar, or they feel too soft, move the stationary pad closer to the rotor. If you are unable to get the moving pad as close to the rotor as you'd like, you can move that one in by turning the barrel adjuster counterclockwise.
- Ensure all bolts are done up, check the brakes work and then test ride in a quiet area.
What are rim brakes?
Rim brakes have been the most popular brake type for many years on road bikes. They provide good braking power without high levels of maintenance. They are controlled by hand levers attached to the brake by a cable. When the rider pulls on the handle the cable moves the brakes and two pads, one on each side, and makes them press against the rim.
One of the advantages of rim brakes are their weight (or lack of) compared to disc brakes. As the braking system isn't as large and is made from lightweight materials, the difference is substantial and will be felt during a ride.
As mentioned above, disc brakes are the MTB favourite. Rim brakes will get dirty on the trail but one) it's nothing a little wash and maintenance never solved and two) rim brakes are better measured for their performance on the road—shaving off valuable speed seconds with all the lightweight qualities competitive cyclists strive for.
Rim brakes are available in a variety of styles and can offer advantages for different types of riders.
Caliper
Caliper brakes attach directly onto the fork or frame by one bolt, just above the tire. Two arms reach down to either side of the wheel. These brakes are most common on road bikes and provide adequate stopping power. Their disadvantage is that they cannot wrap around thick tires, and the fork and frame need holes for the bolts to pass through.
There are various types of caliper brakes, but they all function on the same principle. Some caliper brakes have the cable to one side while others have the cable directly in the middle. There are also dual pivot caliper brakes that have one arm pivot at the centre and the other attached to the side of the inside arm pivots.
This makes them easier to adjust and allows both pads to connect with the rim at once.
Cantilever
With a cantilever brake system, the brakes are mounted directly to the frame, extending to the side. There are two separate arms and each on attaches onto each side of the fork and seat stays. The frame/fork must have fittings for the bolts to attach to.
The cantilever brakes are a rim brake commonly found on mountain bikes as they provide more power for the steeper inclines. They’re also not affected as much by the conditions and are not inhibited by thick tires like the caliper brakes.
V-brakes
V-Brakes are a variation on traditional cantilever brakes. They are sometimes called linear-pull brakes or direct-pull brakes. The difference between V-brakes and other rim brakes is that the cable comes in from one side. With two long arms providing leverage when the brake cable pulls, there's plenty of power on offer and the best V-brakes will perform great in all but the dirtiest terrains.
How to adjust rim brakes
- Squeeze the brake lever to see where the pads hit the rim. Both brake pads should be coming into contact with the rim of the front tire at the same time in the centre.
- Use an Allen key to loosen the bolts holding the brake pads in place. Don't loosen the bolts completely or the brake pads will come out of the brake pad holder.
- Move the brake pads up or down in the brake pad holder.
- Re-tighten the brake pad bolts with the Allen key.
The following points are very general, and cyclists should always refer to the manufacturer's websites for exact advice...or even better leave it to the professionals and use your local bike shop and book your bike into their workshop.
So which is best?
The 'best bike brakes' will completely depend on what you want to achieve from your ride. The main difference between them is as simple as where they are positioned, other than that there are lots of variables.
Rim brakes are lighter, more aerodynamic, easier to maintain and install and usually the more affordable option. However, the brake pads tend to wear, disc brakes are more powerful and sometimes wheel width can be restrictive.
Disc brakes are more suited for tougher terrains and can provide more braking power for longer but with a heavier feel and sometimes 'overly powerful' capabilities, this system could be complete overkill for your next race. Think about it, if you're riding on a lovely sunny day on a smooth road surface with the need for speed...increased braking could work against you.