The Rotor UNO hydraulic groupset was launched to be the lightest hydraulic groupset on the market. But is an hydraulic groupset an advancement in componentry, and can it rival the existing players? We put this exciting groupset to the test to find out.

How does the Rotor UNO hydraulic groupset work?

Looking at the current solutions on the market and their principle function it’s simple to break down. Mechanical groupsets work with metal cables, electronic ones with wires (or wireless) and hydraulic ones with a non-compressible fluid. A big advantage of hydraulics is supposed to be the precision and smoothness of their set operation, for example braking. Hydraulic disc brakes are renowned for more consistent and better modulation than their caliper or mechanical counterparts.

The concept of hydraulics is the same…
…whether it is on a groupset or brakes.

Rotor position their groupset on the spectrum somewhere between mechanical and electronic groupsets. Although priced at € 2,500 seems that they are positioning it on par with electronic groupsets. Besides precision another benefit that you have with hydraulic is because there aren’t any metal cables there is no stretching with use or friction, which should mean consistent smooth shifting. Rotor also make the point that you can have this level of smooth shifting without having to worry about charging batteries. An advantage which could find some fans for long distance events.

Having hydraulic derailleurs does not mean they have to be bulky…
…Rotor UNO sleek design helps the groupset maintain a low weight.

Having hydraulics on the bike isn’t a huge issue either as we are already accustomed to it with braking systems, but bleeding the system to release air bubbles can be a bit of a technical job. Although a groupset shouldn’t suffer as much from this as brakes do because it does not face such high temperatures.

Rotor UNO Specification

Total weight for the disc version is 1655 g, which includes shifters, front and rear derailleur, filled, uncut hoses, postmount calipers, 160 mm brake rotors, chain and cassette, which surprisingly makes it the lightest hydraulic dics groupset on the market, beating the hydraulic version of the Shimano Dura Ace Di2 by a whopping 417g and the SRAM’s Red HRD by 10g.

Here’s what that 1655 g includes:

Rotor UNO Shifters
Front and rear derailleur
11-28T Rotor UNO cassette
Magura MT8 Brake Calipers
160 mm brake rotors
118-link Rotor UNO chain
Filled, uncut hoses with environmentally friendly Magura Royal Blood mineral oil
Price € 2,500

The braking power of the Magura MT8 calipers…
…are really impressive and confidence giving.

Testing the Rotor UNO Groupset

Right from the start the Rotor UNO impresses with incredible braking power. They are reliably aggressive when stopping power is urgently required and braking modulation is excellent, which is down to them being fitted with the MT8 mountain bike callipers from Magura. The brake levers also have a good ergonomic shape that fits well in the hand but which then let themselves down by the shape of the rubber hoods lacking fit and detail compared to competitor ones. This doesn’t really scream great quality, especially considering the price tag.

Unfortunately the shifting on the Rotor UNO groupset is disappointing with more effort needed to shift, especially on the front derailleur.
The flimsiness of the shifting levers further exaggerates the force needed to make the shift.

Whilst we’re on the matter of the hoods let’s talk about the shifters; the double-tap shifting system feels familiar from SRAM but that’s disappointingly where the familiarity stopped. Rear cassette shifting was ok, and felt on par with a mid-range mechanical shifting groupset, although more force is needed to shift than on a mechanical. But the real disappointment was when shifting from the small to large ring on the front, which was basically a disaster. To change gear meant having to push the lever so far across it felt like it was never going to make the shift. This was not helped by how flimsy the lever felt, there is too much flex in the lever itself exaggerating the amount of distance the lever needs to travel to function to go up a gear.

Hydraulic systems should operate much quieter than mechanical ones and on the Rotor UNO the shifting itself was reasonably quiet. But this possible advantage was lost when shifting on the larger aluminium cogs of the cassette. Although we definitely have to mention that the hollow design of the cassette weighs just 135 g for the 11-28 version which is 58 g lighter than a corresponding Shimano Dura Ace Cassette.

Another gripe our test team had was on the last shift or the end of the range. If you attempt to shift to an easier gear when in the largest or easiest cog on the rear cassette most groupsets ignore the shifting attempt. But the Rotor UNO turns the intended double tap into a single tap and shifts to a harder gear. Not what you need when climbing a 10% gradient begging for some mercy from an easier gear!

But we are happy to give praise where praise is due, and the button on the rear derailleur that with a quick press moves the chain onto the smallest cog (in this case the 11T) on the cassette, gifting you speedy wheel changes to rival the pro-peloton.

Then a part of the bike we were all excited about: the oval Rotor Q Rings that were fitted with the groupset we tested. Although the cranks aren’t included in the price, this recommended crankset by Rotor is a nice touch. Instantaneously on the flat we felt the smoothing out of the dead spot near the top of the pedal stroke, which felt like you were getting more out of each revolution, which is always a welcome sensation. The integrated power meter is another bonus that Rotor cranks offer, but this groupset can equally be fitted with round cranks, both with or without the power meter.


So is shelling out €2,500 on a fully hydraulic groupset worth it? The Rotor UNO could be made into a really well functioning groupset if there were a few important tweaks made to the shifters, because this is mainly what really let the groupset down with its severe lack of precision which is nowhere near electronic groupsets. But where braking is concerned, you couldn’t ask for much more from a set of disc brakes, they are really confidence giving. On the groupset as a whole we definitely see it as an alternative to a mechanical one but it loses huge amounts of ground on the electronic counterparts. Looking at the advantages of the Rotor UNO it could be a good companion for cyclists who regularly venture out on long distance travels or races, especially if you consider running it as a 1×11 setup. But, is this an advancement in the current groupsets on offer in the market? Unfortunately not. In the current climate where electronic and digital components are trailblazing the way forward this doesn’t come close. It’s an exclusive product, maybe one for the cyclists out there who enjoy systems that are a bit more technical.

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Words: Hannah Troop Photos: Valentin Ruhl