First look: Rotor Uno hydraulic drivetrain

We got to play around with Uno, Rotor's new hydraulic road group, at Eurobike. Here are some thoughts.

Rotor’s Uno hydraulic drivetrain will be entering the market in spring 2016 and will be on team MTN-Qhubeka’s bikes for next season. We haven’t had a chance to ride it yet; that will come at the company’s press launch this fall. But we did get to play around with the system at Eurobike, as well as talk to Rotor co-founder and chief innovation officer Pablo Carrasco about how the system works and how it came to be. Carrasco also confirmed that MTN-Qhubeka will race Uno for the 2016 season.

First off, Rotor did not, as many have assumed, simply buy Acros and rebadge it. This is a brand-new system from the ground up. It uses just one line to each derailleur, versus two. It also shifts much more smoothly and pleasantly, at least judging by our limited time on the trade-show demo. Uno will come with either disc or hydraulic rim brakes. Carrasco says the group will cost roughly the same as a Dura-Ace Di2 group and that, with hydraulic brakes added to the mix, the full package will weigh about 350 grams less than a Di2 setup.

The brake and shifting systems work independently of each other. The former is a typical open system with a piston and reservoir. The drivetrain is a closed system that moves oil through a cylinder on the derailleur. A second cylinder contains a spring that shifts in the other direction. Uno can move up only one gear at a time, but the user can customize down shifts to dump up to four gears at once, which the system seems to do with remarkable speed and precision.

Of course, with SRAM’s new wireless Red group — plus the growing number of single-chainring builds out there — the industry trend is definitely toward simpler drivetrain solutions. Uno flies directly in the face of that. No way around it. In theory, the closed system should have to be bled only on initial setup. But that’s one more time than even people who know how to bleed hydraulics probably want to do when setting up a drivetrain.

On the other hand, with pros now experimenting with hydraulic disc brakes in UCI races, the number of riders and mechanics who can deal with hydraulics will only grow. So perhaps there will be a receptive market. And, of course, a hydraulic system does offer advantages in terms of routing and maintenance. The friction caused by all the bends and twists that come with internal routing isn’t a concern here. And because it’s a completely closed system, there’s no need to replace cables every season or after muddy rides.

Rotor’s move into drivetrains, and the decision to go with hydraulic, were in large part due to more pragmatic reasons, however. Carrasco said the company began looking into creating a drivetrain about six years ago due to sponsorship concerns. “We had teams riding our chainrings, but they had other drivetrain sponsors who were always putting pressure to use their chainrings,” he says. “They were always trying to kick us out.”

The company expanded into cranks in hopes of allaying some of this pressure. But Carrasco said it became clear that the only way for Rotor to retain a foothold in pro sponsorships was to develop its own drivetrain. The company experimented with different mechanical solutions but ran into intellectual-property issues. “In the end, some patent or the other was stopping us at every step,” he said. “Then it became clear that electric was here to stay. So we had to do something that would let us offer something different and that would be one step ahead.”

That thing was the Uno hydraulic system, which Rotor developed in conjunction with the hydraulic experts at Magura. Carrusco said MTN-Qhubeka will be on the group for 2016. So, regardless of market adaptation, Rotor is confident that Uno is WorldTour ready.