Rim brakes or disc brakes? the best choice for your bike as you commute to work.
Reliable brakes are a must on any bike. You need to stop especially in traffic.
Rim brakes work by using your wheel’s rim as the braking surface. There are various different caliper styles available but all use brake pads, that attach to the caliper.
The caliper connects to the brake lever via a cable. Pull the lever and the tension added to the cable will pull the caliper arms towards each other, eventually ensuring that the pads meet the rim.
Modern road bikes with rim brakes use a dual pivot caliper. A hybrid bike with rim brakes will instead use linear pull brakes, better known as V-brakes. Unlike road calipers that mount centrally to the frame, V-brakes mount to the forks and the seat stays.
Disc brakes are becoming almost standard on all modern bikes. In simple terms, disc brakes move the braking surface from the wheel rim to a specially-designed disc or rotor attached to the hub of each wheel.
The calipers mount on the fork and on the chainstay. Using the brake moves a piston in the caliper that pushes the pad or pads onto the rotor. Disc brakes can be cable-actuated, like rim brakes, or hydraulic.
Framing your limitations
If you want to upgrade your current commuter bike’s brakes you’ll need to take into consideration some points.
Your bike frame is designed around a particular style of brakes. Thus, a switch to another style might not be possible. How the brake calipers mount to the frame depends on the style of brake.
V-brakes need a frame with special mounts or bosses on the fork and seat stays. Likewise a road bike frame using dual pivot calipers has specially drilled holes in the fork crown and in the seat stay bridge to let them to be mounted correctly. This set up indicates that the road bike’s frame won’t have the necessary mounts for a V-brake caliper and vice versa.
Disc brake standards
Disc brakes also require a compatible frame, and how the calipers mount to the frame and forks has evolved over time. Rather than one ‘standard’ disc brakes fall into three categories: I.S mount, post mount and flat mount:
I.S mount: Standing for International Standard, this mount attaches the caliper to the frame and forks with two bolts that are 51mm apart. It is no longer standard!
Post mount calipers fit onto threaded ‘post’ mounts on the frame and fork. The bolts run through the caliper, giving easier adjustment when setting up your disc brakes;
Flat mount is the newer standard and the one you’ll most likely have on the latest disc road and gravel bikes. Here, the front caliper mounts to an adapter and then bolts to two threaded inserts on the fork. The rear caliper eschews the adapter and instead uses two bolts that run through a ‘flat’ surface on the frame before threading into the caliper body.