ROTOR UNO ROAD DISC BRAKE GROUPSET FOR FLAT-MOUNT BRAKES

Light, reliable, never goes out of adjustment. Rotor’s UNO Road Disc Brake Groupset goes in a completely different direction than their competitors. They use hydraulics to both stop the bike and shift the gears. It’s a simple, reliable system that changes the paradigm for shifting.

Before getting into the changing paradigm, it is important to get into what Rotor wisely jobbed out. The brakes. Magura is a master at hydraulic brakes, with well over 20 years experience building them. So Rotor decided to utilize a proven Magura design for their disc brake calipers. They went with the MT8 calipers. This is Magura’s top-of-the-line cross-country brake set. These feature two-piston aluminum calipers that pulse with Magura Blood mineral oil fluid. The calipers come as either post-mount or direct-mount, so please specify when ordering. This simplifies mounting and reduces weight. They are designed to work best with Magura’s 160mm six-bolt rotors.

What sets Rotor’s shifting apart is the use of hydraulic fluid to move the derailleurs. The beauty of fluid is that it has little friction and never stretches. Because there’s no heat involved in the shifting, it can be a ‘one-and-done’ operation. Temperature will affect the fluid, but a simple barrel-type adjuster will allow you to compensate for heat or cold.

The integrated brake and shift levers feature carbon-fiber brake levers and shift blades. These are slightly canted outward to make the reach from your handlebars more comfortable. The reach of the levers is adjustable so that people can find their ideal distance from the bars to the levers. The shift style of the levers is similar to SRAM’s Double-Tap in that a short throw shifts down and a long throw goes up.

Further, the shifting mechanisms are attached to the derailleurs, not the shift levers. There are eleven positions for the rear derailleur, and four for the front. As a result, you don’t need both low and high stops. There is just the starting-point adjustment. Once that is set, the derailleurs take care of the rest. The rear derailleur even has built-in adjustment screw that tunes how many upshifts you can do with one throw. You can set the shifting to do one cog at a time, or up to two, three, or four cogs at a time. They also designed a simple lever to take the spring tension off the rear derailleur, a feature that can come in handy when traveling with the bike.

The derailleurs themselves are also different than what you’re used to. The front derailleur’s inner cage plate is longer and lower than is typically seen on front derailleurs. It looks similar to the inside plate of a front mech set up for triple cranks. The reason for this is Rotor designed the front to work with both No-Q (round) and Q (oval) chainrings. As they produce both, they wanted to be the only derailleur manufacturer that offered a purpose-built option for people who prefer non-round rings. The rear derailleur works with cogs up to 30 teeth, and, in a surprise for a company specializing in machined aluminum, includes a carbon-fiber outer cage plate. They found it made sense in terms of weight and stiffness.

The spacing on the rear derailleur works with all eleven-speed cassettes on the market. But it works best with Rotor’s super-light 11-28 teeth cassette. 135g for the entire cassette. What helps in the weight savings are that the two tallest cogs, the 24 and 28, are machined out of a single block of 7075 aluminum and bolted to the machined steel block of nine cogs. The shifting is excellent thanks to Rotor’s Flowdrive pattern of cuts and ramps. All the cogs are treated with a low-friction coating.

The cassette needs a chain. Rotor also outsourced chain technology, this time from KMC. Their X11SL Chain is anodized black with red pins to separate it from the pack. It also features cutouts in all the plates for weight savings, hollow pins, and shapes that speed shifts.

The hydraulic lines come filled with Magura Royal Blood. They were also bled at the factory, so, theoretically, all you need to do is hook up the lines. However, if you want to shorten them, you’ll need at least a razor blade, if not a hose cutter for the task. The shift lines won’t need to have the lines bled and re-loaded, though the brake lines should be bled and reloaded as per Magura’s schedule. The UNO group also comes with all the tools and fittings you’ll need to install and adjust the group. You will also need to source a crankset and bottom bracket. R&A offers a wide selection of cranks and bottom brackets, as well as all Rotor has to offer on that front. And, as the front derailleur comes in braze-on style only, if you need a clamp to secure it to the frame, you’ll need to source that as well, though we have all the options you could want. And, in case you’re fearing that this group will limit you to only riding disc-brake bikes, know they have a rim-brake version, and you can just swap the rotor calipers for rim calipers.

The Rotor UNO Road Disc Brake Groupset is the kind of innovation you expect from Rotor.