Shimano hasn't always been known for the most elegant industrial design and the cyclocross-focused BR-CX77 mechanical disc brake is no exception. The polished dark grey finish may be impeccable (no surprise there) but it's otherwise not much to look at. None of that matters when you're riding it, though, because the only thing your fingers will notice is how well it works.
The CX77 shares its basic design with Avid's long-running (but still excellent) BB7, with a fixed inboard pad and a dynamic outboard one. The concept is as simple as it sounds: pull the brake lever and the outboard pad then pushes the rotor over into the inboard pad.
Just as with the BB7, proper adjustment is essential for optimum function with the key element being very close spacing between the rotor and inboard pad. Get that nailed down, however, and there's very little to complain about. Thankfully, Shimano makes the process easy with independently adjustable inboard and outboard pads, which also helps later down the road as the pads wear (which will happen quickly in muddy conditions given the stock resin compound).
Power is more than adequate, with a solid initial bite that builds predictably and progressively with increasing cable pull. They run quietly, too, plus the smooth-running internals and appropriately strong spring tension yield a silky, low-friction, and snappy action at the levers.
Though the calliper looks a little clunky, it's impressively light at just 164g for the calliper, mounting bolts, and pads – 24g lighter than a comparable BB7 and 11g better than Avid's much more expensive BB7 Road SL. Helping matters along are the stock aluminium-backed pads that typically aren't included with hydraulic brakes given their lower heat capacity (which obviously isn't an issue here). Even better, the CX77 is about 10mm narrower as well, although it's split roughly even between the two sides so the real-world boost in heel clearance is fairly modest.
- Pros: Lightweight, excellent power and modulation, easy setup
- Cons: Industrial aesthetics, lots of different tools required, no rotor or barrel adjuster included
Niggles are few and far between.
Though it's mostly a convenience thing, there's no barrel adjuster integrated into the calliper to ease cable setup. Mechanics will likely take issue with the fact that they'll need four different tools to work on the thing: a 3mm Allen key for the inboard pad adjustment, a 2.5mm one for the outboard one, a 5mm one for the mounting bolts and a small flathead screwdriver to remove the pad retaining pin.
It's good that Shimano has incorporated independent inboard and outboard pad adjustments but only the inboard one is detented
Potential buyers should beware of the deceptively inexpensive asking price too, because there's no rotor included.
Otherwise, there's little arguing with how the BR-CX77 functions, and in those terms, it's a great piece of hardware.