Everything About Rotor UNO Hydraulic Drivetrain & How it Works

Everything about, and the Best About Rotor UNO Hydraulic Drivetrain. In the autumn of last year, Rotor UNO was introduced to the public as the inaugural full hydraulic transmission assembly, providing all the necessary components from shifters, derailleurs, cranks, cassettes, and even brakes. This system was distinct because it allowed for changing gears by pushing the liquid in just one direction.

The alterations exceed simply linking components through liquid – all elements which require motion in the shift are located at the derailleurs, and not the shifters. In conjunction with impermeable hydraulic pipes, this provides a sharp, instantaneous response with a traditional mechanical sensation.

The group is close to producing their product, and they now have the technical features, measurements, and initial tests completed. We also discovered the origin of the organization, the modifications that have been made, and why Rotor believes you will take delight in it.

UNO is an evolution. Rotor began at the beginning, creating chainrings, then moved on to create cranks, and finally a series of power meters. This is the next step.

Even if they weren’t aware of it, the long process of creating round chainrings that could function with the derailleurs and chains of other manufacturers resulted in a great deal of new knowledge about shifting.

Beginning in November 2015, UNO initiated athlete testing and gathered more data in a few months than was collected in the entire 12 months before that. As a result, they were able to make numerous changes to the system.

Rotor feels that the UNO offers the best of both the electronic and mechanical group worlds. This group of brakes is much lighter than any other group with hydraulic disc brakes. You receive the majority of the precise, direct sensation of a mechanical system.

The design of this system is similar to electronics, making it very easy to switch out what type of shifter it is using: All that needs to be done is to connect one end of the hydraulic line to its other end. That is an indication of potential growth in the future, such as track and field, triathlons, or even mountain biking.

The duo is referred to as HySTEP, which is an abbreviation for Hydraulic Smart routing. This pertains to the thin and bendable tubes that can be easily inserted into aeroplane frames and slender tubes.

The main advantages of using hydraulics are a smooth and friction-free shift every time. Given that there is no requirement to consider heat expansion, it is a self-contained system that will remain forever coordinated with almost no servicing needed.

No batteries to refuel, no cords to scrub or restore. It’s also future-compatible with additional hydraulic systems.

Benefits of hydraulic shifting

Friction causes mechanical shift cables to perform poorly when routed through tight twists and turns with tricky internal routing pathways. Hydraulic lines are not affected in the same way so all the new aero-integrated bars and sharp frame shapes won’t cut down on shifting crispness.

Hydraulic shifting is also lighter than both electronic and mechanical systems. Because of the low volume and low pressure needed for shifting movements, Uno uses 3mm diameter hydraulic lines (compared to 5mm brake lines). Less material means less weight and Uno is a claimed 417 grams lighter than Shimano Di2 disc and 99 grams lighter than SRAM eTap. These hydro lines are so small that they fit through Di2 internal routing holes in bikes currently on the market. Naturally, no heavy batteries are required either.


  • Closeup of the ratcheting mechanism’s dual stops. As the top one pushes it one way, the bottom one catches and holds it. To shift the other direction, the bottom one pushes and the top one catches. Which one does what depends entirely on how far you push the shifter.
  • The front derailleur uses a three-step clocking. Two small ones for trim settings on each chainring, and one big one to shift between gears.
  • The rear derailleur has 11 steps. As the clock gears turn, they move the rack you can see on the outside bottom. That rack is linked to the parallelogram that actually moves the derailleur.
  • UNO can downshift (easier) up to four gears at a time, and a single upshift (harder) at a time.

The shifting system operates with a 30% glycol solution that holds up over a broad temperature range, ranging from -15º to 88º C (5º to 190ºF), instead of mineral oil or DOT fluid. The tubing passes through a 3mm bendable shift hose, making it uncomplicated to route even in tight turns.

Rear Derailleur

The two tubes and the circular object located at the end of the back of the rear derailleur contain all of the timing and mechanical gear systems.

The reason the clocking mechanism is situated on the derailleur rather than the shifter body is that it ensures an extremely accurate operation.

The teeth on the ratchet have been perfectly matched to the spacing of the gears, ensuring that it will consistently make the same exact shifts over and over again regardless of variations such as cable slack, temperature, etc.

During the initial installation process, the alignment can be fine-tuned using one screw and an additional upper limit screw. Afterwards, the number of downshifts the lever is capable of activating can be allocated between 1 and 4.

The number of shifts you can obtain by pressing that baton (green arrow) is determined by how many lines it has. It’s not an all-or-nothing situation…you have the option of changing through one, two, three, or even four gears slowly.

They changed the design because some sprinters wanted to be sure that, when they pushed the lever hard at the end of the race, it would cause the bike to shift in only one gear each time. If you’d like to be able to shift a significant number of gears all at once, you can configure it to suit your preferences.

Return to Origin is among the most fascinating features. If you by any chance end up damaging the hydraulic lines, you can push the grey lever forward and disengage the clocking system, meaning the derailleur would drop onto the smallest gear.

Before you operate it, shut the switch and then use your strength to move it to the necessary gear. You could switch to a lower gear when going uphill and to a higher gear when going downhill.

This could be useful by speeding up wheel changes and shielding the derailleur from harm while being transported.

It is noteworthy to mention that Rotor’s Madrid factory is the sole source for the design, production and assembly of all components in the group, excluding the return spring and hoses.

Every metal piece is either milled or stamped locally, giving the same look as their pedals and sprockets, resulting in a seamless, exceptional-looking assembly.

At the bottom, you can observe the screw for the ceiling, rack, and gear alignment, as well as the clamp on the tube. You should only have to locate the bleed port on the side of the device for the initial setup. The collection features a length of hosepipe and a container of liquid.

Front Derailleur

The front derailleur has a single screw that can be fastened and unfastened quickly and easily for adjustment. No bolts are necessary on the front due to the presence of a clocking device, which establishes the alternate positions that can’t be changed; once it is fully set, no further limitations have to be established.

The inside of the parallelograms has a rack that is connected to the clockwork, which activates the arms connected to the big circular gear. A spring that brings it back allows the item to drop onto the tiny hoop.

Shifter and Brake Lever

One of the principal distinctions between the pre-production and finalized models is that two distinct shifter lever bodies will be available, one for rim brakes and the other for disc brakes.

Disc brakes have an open design which allows heat to build up, and they use a master cylinder that holds liquid to take on the increased volume as they warm up. Hot temperatures do not cause problems for rim brakes, so it runs using a sealed system, so no maintenance will be needed at any time.

Investigations conducted by them revealed that riders preferred a slightly bigger bonnet, although the real parts are not very large. However, they will offer smaller hoods in the future. The bulging hump in the front is intended to be that way, which gives a more secure sensation.

The brake lever is composed of carbon and is designed with a manoeuvred reach-adjuster which can be accessed from the top of the cover. The gearstick is made out of metal and is connected to the handbrake, therefore there aren’t any extra reach control modifications or changes in position. As the gear selector is moved, a piston is pushed, causing fluid to be sent to the derailleurs.

A light press of the derailleur will allow for an increase in gear ratio, and a firmer push of the gear shift will give you 1, 2, 3, or 4 lower gear changes, depending on how you have your rear derailleur configured. The rear derailleur has a two-way ratchet system that prevents it from slipping if the shifting motion is not completed after initiating it.

Precise and Quick Shifting

The Uno group does not offer half-shifts, it is an all-or-nothing situation with them, unlike with some mechanical shift systems. This is because the gear-changing system, known as HyStep, is actually incorporated into the derailleurs rather than in the shifter housing.

Whenever you change gears, the derailleur will move a specific distance to create a smooth and accurate transition to the required sprocket.

Mechanical systems use cables to activate the process and if you don’t press the lever completely, the chain can become stuck in between gears and will move to vacillate between cogs until it finally rests on either one or the other, or until you shift again with a full thrust.

Uno proved to be very swift when it came to switching up gears, in particular its rear derailleur. Activating the right button caused the derailleur to act swiftly in both directions.

We didn’t experience any delays like we have seen with some digital systems, and that can be annoying when you’re rushing or when you want the immediate thrust to go faster.

The front derailleur had a bit of difficulty and was not as responsive, particularly when starting to climb up hills and transitioning the chain from a larger chainring to a smaller one.

A part of my observation may have been the consequence of the Rotor Q-rings I had on my demo bike, with the ovoid shape keeping the chain too long in a pulled state when I pedalled with effort.


Due to Uno’s positioning system being situated within each gear changer, the guts of the shifter body are relatively minimal, allowing Rotor lots of space in which to decide on the appearance and dimension of the fresher body designs.

The engineers chose hoods with a pleasing appearance that is neither too high nor too wide, similar to the kind available from Shimano and SRAM. The majority of journalists present at the unveiling found the hoods to be cosy and the correct size, yet I did not like that they were a bit too broad.

My small hands enjoyed the elongated shifter lever that let me pull them in towards the shift body so that my delicate digits had a secure grip.


Each item of the Uno set will be manufactured in Madrid and afterwards sent to Germany where Magura will assemble the hydraulic systems and liquids. The group of items will then be packaged together and sent to locations where they will be sold, such as distributors, retailers, and directly to purchasers.

To install the hydraulic shift lines within the bike, it is necessary to cut the line, guide it through the bicycle, and then reconnect it to the derailleurs.

Imagine covering one end of a drinking straw with your finger and then removing it from your food or beverage – nothing will pour out of the opposite end, right? To help ease your anxiety about having to cut any water piping, keep in mind that this is a sealed system.

The hydro fluid should stay within the system’s piping, allowing for it to quickly be hooked back up to the derailleurs.

When first setting up, modifying both the front and rear derailleurs is easy and only requires that one bolt be aligned.

Position the back derailleur in line with the smallest gear by tightening the bolt. After that, the already configured shifting intervals will move the derailleur up and down the cassette, allowing for accurate changes between all the gears.


UNO’s offerings come with two options, either rim brakes or disc brakes, both of which utilize Magura’s hydraulic system and Royal Blood hydraulic fluid- an environment-friendly mineral oil.

The rim brake system is similar to the hydro shifting system in that it is a closed system and should not require any maintenance apart from regular checking, with no necessary need for bleeding.

The disc brake system (in either post-mount or flat-mount versions) is an open system as a result of the heat created by disc brakes, which needs the space for fluid to be able to expand when it becomes hot.

Therefore, the disc brake system has tanks to handle any increased fluid pressure, and they must be serviced like any other disc brake would require. Luckily, there is a readily available bleeding port on the transmission assemblies.

Nuts and Bolts

Rotor states that the overall mass of their Uno hydraulic disc brake is 1,604 grams. Shimano’s Di2 disc is around 417 grams heavier than the SRAM Red 22 disc, which is 10 grams lighter. (Note: Weights for all three groups are without cranksets.)

Uno is being offered at a recommended retail cost of £2,200 or approximately £2,050. The pricing of a Dura-Ace Di2 hydro disc group on Competitive Cyclist’s website is around £2,150, which is also the same price as SRAM’s Red hydro group.

The full set of parts consists of a front and rear derailleur, both disc or rim brakes, shifters, hydraulic lines and liquids, a Rotor-crafted 11-28 cassette, and a KMC X11SL chain.

Rotor does not want to include a crankset in the group because they feel that there are too many combinations of chainrings and cranks available. Therefore, they want cyclists to be able to pick the right one for themselves, rather than have to use something because it comes with the set.

All the components of the Uno set except the KMC chain are created in Madrid, Spain. Rotor handles all testing for quality assurance in-house and can make small alterations to the collective in a shorter period than when using makers in foreign countries.

This group will have Rotor’s recently fashioned three-part cassette, Uno, and it is interoperable with SRAM or Shimano; this way you do not have to throw away your current cassettes, chainrings, or wheels.

It is currently in the process of creating satellite shifting alternatives such as time-trial shifters or sprint and climbing shifters, however, these will not be instantaneously accessible to the Uno group. Rotor claimed it should be easy to connect an extra hydraulic line to the system if additional shifters are wanted.

Uno is scheduled to be released in July and will be sold as an aftermarket item. Rotor states that they are in the process of obtaining OEM contracts for a range of bicycles produced in 2017.


Related Articles

Leave a Reply

Your email address will not be published. Required fields are marked *

Back to top button