A little over a year ago I wrote one of our “Stuff We Like” articles about cable-actuated (aka “mechanical”) disc brakes. In a nutshell, I said that while I prefer the aesthetics of traditional brakes, I enjoy mechanical discs for their performance advantages. Here’s an excerpt:
“While I prefer the aesthetics of a delicate, high profile cantilever or a classic, dual-pivot caliper, I have to admit that nothing quite beats the overall performance of a high-quality, cable-actuated disc brake (also known as “mechanical” disc brakes). Drum/roller brakes are heavy and generally provide only mediocre braking performance, and most every other type of performance brake uses the rim wall for a braking surface, a fact that guarantees your rims will be toast long before your hubs go. Rim brakes can sometimes be poor performers in wet conditions, they make an awful mess in the rain, and the caliper variety rarely provide sufficient clearance for robust tires and fenders.”
Now that I’ve been running mechanical discs on my daily commuter for about a month, I thought I’d point out again how much I like these brakes. They’re powerful, easy to set-up, weather-resistant, and clean as a whistle in the wet. Following are a few of their advantages and disadvantages:
- Easy to set-up
- Not affected by out-of-true rims or broken spokes
- Weather-resistant performance
- Boat loads of tire/fender clearance
- Require a beefy fork
- Front wheel must be dished
- Require disc-specific frame mounts
- Rotors can be fragile
- Can interfere with rack and fender mounts
Hydraulic discs provide even better performance than mechanical discs due to the elimination of cable drag and housing compression. From a pure performance standpoint, they really can’t be beat. That said, working on hydraulic discs can be a challenge. A relatively simple thing like swapping out handlebars can get fairly involved when you’re looking at changing the length of hydraulic lines and bleeding brake systems. For me, the simplicity of cable-actuated discs outweighs the performance advantage of hydraulic discs.
I’m running Avid BB5’s on both my grocery getter and commuter (Civia Loring, Civia Bryant). While I prefer the BB7 caliper for its ease of set-up (the BB5 only has one pad adjustment knob, whereas the BB7 has two; one for each pad), the performance of these brakes has been flawless and on par with my best rim brakes. Now that I’ve gotten the hang of it, setting-up these brakes is at least as easy as setting-up calipers and V-brakes, and I find them easier to set-up than cantilevers.
Mechanical discs aren’t necessarily for everyone, and they’re certainly not a good aesthetic match for old school bikes, but they offer a number of advantages and make a lot of sense on modern commuters and cargo haulers.