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Rotor's new hydraulic disc brake groupset spotted in the wild for the first time, on a Cervelo R3 Disc road bike

MTN-Qhubeka team rider Daniel Teklehaimanot has been spotted, thanks to an image helpfully shared by Rotor, test riding a Cervelo R3 Disc with Rotor’s new Uno hydraulic groupset, the first time we've seen the groupset actually on a bike. Admittedly we haven't got very close to this one, but it'll do for now.

This isn’t the first pro team we’ve seen on disc brakes. Team Sky has been at it and so has Trek. The WorldTour teams have been allowed to trial disc brake road bikes during selected roads in August and September, and some have been higher profile than others. We’re keeping our eyes peeled for them.

- Hands on: Rotor Uno groupset

Cervelo launched its new R3 Disc road bike at the recent Eurobike show. Speaking to the people at Cervelo, it’s clear the company has been looking at disc brakes for a number of years - it has been working on disc brakes since 2011 in fact - so it hasn’t been taken completely by surprise by the recent development of disc brakes and testing by WorldTour teams in races during recent months.

Something else that Cervelo let slip to us at Eurobike a year ago, is a new internal cable routing system that is future-proofed against any new groupset developments, including hydraulic systems. This was a year ago and nobody had any idea that a year later Rotor would do an unveil its all-new hydraulic groupset, Uno. So we can see Cervelo knew a hydraulic groupset was forthcoming and made sure its frame was compatible. 

Rotor’s Uno groupset was revealed to the world for the first time at Eurobike last month. It’s a complete groupset, with hydraulic shifting and braking, with a choice of rim or disc brakes. It has been developed with Magura, a company that has loads of experience with hydraulic brakes.

- Team Sky races with disc brakes for the first time

We haven’t ridden Uno yet, but we have had a play with it on a special stand that Rotor cobbled together at the show. You can read our in-depth hands-on report here. To recap, the biggest advantage of Uno over electronic groupsets is the lack of batteries - this thing will never run flat. It’s a completely sealed system as well, so the gears and brakes will be impervious to dirt, and there are obviously no gear cables to stretch.

- Cervelo R3 Disc spotted at Eurobike

Uno is a 22-speed drivetrain with a separate hydraulic system for the shifting and braking, each having a master cylinder in the lever hood. To use, the gear shifters work in a similar style to SRAM’s DoubleTap: a short push drops the rear mech down, a longer push shifts in the opposite direction.

- Trek trials disc brakes at the Vuelta - and reaction is positive from the pro riding them

That’s about all we know on the groupset front at the moment, there's no word on pricing or availability. We do have some more details on the Cervelo R3 Disc bike however. The new frame has identical geometry to the regular Cervelo R3, right down to the same chainstay length. The current issue with adding disc brakes to a road frame is the widening of the rear axle, which on a bike with short chainstays can lead to chainline issues. Most endurance bikes get around this by simply having longer chainstays.

A race bike is pretty much defined by the shortness of its chainstays however. Keeping them short is seen as an important thing. Specialized has gone to great lengths to solve this problem on its Tarmac Disc, developing a new hub with special dropouts and a mech hanger that places the cassette further inboard. Focus took the simpler approach and simply lengthened the chainstays for its new Izalco Max Disc.

Cervelo however has a different approach. It has worked with FSA to develop a modified chainset with the driveside crank pushed outboard by 5mm, which sorts the chainline issue and maintains the same chainstay length. That's quite clever and means you're not restricted to one set of wheels, as is the case with the Specialied Tarmac. Other interesting details are the asymmetrical seatstays, space for 28mm tyres and the use of12mm thru-axles front and rear.

That's all for now, more on disc brakes in the pro peloton soon, no doubt.

David has worked on the road.cc tech team since July 2012. Previously he was editor of Bikemagic.com and before that staff writer at RCUK. He's a seasoned cyclist of all disciplines, from road to mountain biking, touring to cyclo-cross, he only wishes he had time to ride them all. He's mildly competitive, though he'll never admit it, and is a frequent road racer but is too lazy to do really well. He currently resides in the Cotswolds.