Review: Rotor’s 13-Speed Hydraulic Drivetrain

by | October 15, 2020

After seeing Rotor’s drivetrain show up in prototype form at various tradeshows, I managed to get my hands on the production version to see how it stacks up against other drivetrains currently on the market.

The group was built around 12-speed spacing, but the derailleur works with 12 or 13-speed configurations via a limit screw adjustment. However, you’ll need to use Rotor’s proprietary hub to get those 13 cogs. Rotor sells the drivetrain as a shifter, derailleur, cassette, along with their cranks and a hub. The 13-speed hub is backward compatible with 11 and 12-speed HG cassettes, and both the 12 and 13-speed groups use a standard KMC style 12-speed chain. Got all that?

Rotor 1×13 Hydraulic Details
• 13-speed
• Hydraulic system
• Adjustable lever feel
• 10-52 tooth cassette
• Weight: 435-grams (derailleur / shifter / hose), 331-grams (cassette)
• MSRP: Base group w/ cranks & hubs: $1,800, shifter / derailleur: $999, 13s cassette: $415, 13s rear hub: $344
www.rotorbike.com

A 12-speed hydraulic group with a shifter, derailleur, chain, cranks, chainring, and 12-speed cassette sells for $1,400. The 13-speed group with front and rear hubs sells for $1,800, and the 13-speed group with Rotor’s 2INpower cranks sells for $2,600. It’s also possible to purchase items individually if, for instance, you don’t need new cranks to go along with your fancy 13-speed drivetrain.

Why hydraulic? According to Rotor, they chose hydraulic to go with a hydraulic system due to its consistency and longevity. Since there’s no heat generated in a shift, the bleed interval can be, according to them, virtually indefinite. It also eliminates concerns about contamination, friction, and cable stretch. Additionally, the patent landscape was a little less cluttered and allowed Rotor more creative freedom to explore what they felt was the best way to make a shifter and derailleur.

Shifter

Rotor’s hydraulic shifter has a removable second paddle, so riders can have a second position for shifting while riding with a different hand position on the bar. In practice, some riders may find it cumbersome, especially for riders used to the Shimano two-lever system, so there is the option of removing it. My test kit came with the lever removed, but the second paddle is still included in the groupset should you want it.

The shifter is much more basic than a mechanical shifter. It is merely a lever with a pin that pushes an actuator to drive fluid to the derailleur, which handles all shifting and indexing duties. Rotor’s team claims that moving the indexing to the derailleur itself cuts down on the bulk and complexity of the lever and its replacement cost should you damage it in a crash. The lever itself works with MatchMaker style mounts and, like many MatchMaker style components, has two mounting holes, one more inboard than the other. Other than that, there’s a bleed port on the lever just as there is on a brake for bleeding the system, with the other port being on the derailleur. The paddle for the lever is broad and smoothly machined.

A short push of the lever enables the derailleur to click into a harder gear. A longer push, on the other hand, shifts the derailleur into an easier gear. If you’ve ever ridden road bikes with a SRAM drivetrain, the action and feel are quite similar to that of the DoubleTap system they utilize. Check out the video below to see the Rotor shifter in action.

It doesn’t get much more straightforward than this, lever pushes actuator, which forces fluid through the line.

Derailleur & Cassette

The derailleur for the system is the same for Rotor’s 12 and 13-speed groups. Indexing is managed in the derailleur, which is a closed system to keep things safe from the elements. All of the adjusting for the system also takes place here. There is a button on the outside of the derailleur that allows it to “go to origin,” dropping the chain down to the small cog for easy wheel changes. Additionally, there is an upper and lower limit adjustment. With the indexing residing in the derailleur, if a rider breaks a line on the trail, the derailleur can be moved into a desirable gear by hand. It will stay there, hydraulic line or not.

The large knurled adjustment on the derailleur is designed so that the limit can be adjusted by hand. For b-tension, there is a stepped b-limit screw that is intended to correspond to various cassette sizes since the derailleur can also work with a road/gravel shifter and, therefore, a much smaller cassette if desired. The barrel adjuster where the cable feeds in controls the lever feel to give more or less feedback from the indexing, allowing for a more firm or softer click when actuated.

The cassette is machined out of steel and aluminum to keep weight down and provide durability in the smaller cogs. The cassette comes in several tooth options in both 12 and 13-speed, with the 10-52 tooth option delivering the widest range. The 13-speed cassette uses Rotor’s 13-speed hub and will not fit on a standard 12-speed HG freehub.

The derailleur is compatible with most other 12-speed cassettes, and it’s the same derailleur used in Rotor’s road system. This makes the shifter and derailleur pretty darn compatible as a system when it comes down to it.

How does it Compare?

In looking at other high-end drivetrains, Rotor wins the battle for the number of gears, with 13. The gearing profile is also slightly different from both Shimano and SRAM’s wide-range systems, which could appeal to some riders. If we break things down into dollars, the Rotor drivetrain, consisting of the shifter, derailleur, and cassette, costs $1,414 when bought a la carte and weighs 766g. Lighter than SRAM’s XX1 Eagle, Eagle AXS, and Shimano’s XTR groups when you factor in a gear cable’s weight. It’s the highest price per gram at $1.85 per gram, nearly a dollar more than Shimano’s XTR, which is $0.94 per gram. That extra gear is expensive but, at $108.77 per gear, it’s still less than the $112.42 that SRAM’s electronic AXS group goes for.

Installation

Installing the hydraulic drivetrain was surprisingly straightforward. Despite some initial hesitation, cutting the line and bleeding the system was a simple process, no different than bleeding a hydraulic brake. Set the limits, b-tension, lever feel, and you’re on your way. In all, after doing it once, I could set up the system nearly as fast as installing a cable fed derailleur and bleeding a brake if I had to do it again.

While the installation was simple, the included instructions were not very helpful. It took a call to Rotor to understand how to make everything work as it should. The process is simple, but the manual was lacking. The instructional videos on Rotor’s website are more geared towards the road system. This was confusing and not confidence-inspiring. While the instructions do carry over to the mountain drivetrain, I needed some reassurance.

The adjustment barrel at the end of the derailleur is used to change the feel of the lever. Twisting it in makes the shifter more firm and indexed while dialing it out creates a much lighter action. While bleeding the system, the dial should remain centered, according to the instructions.

The limit screws were easy to adjust. However, the knurled dial, which is made to be “tool-free,” according to Rotor, wasn’t always easy to move and it took using a T-30 to adjust it, a tool not very common on most multi-tools.

Performance

The system takes some getting used to, but it became more intuitive over the test period. Only when the barrel adjuster on the derailleur was fully dialed into the firmest setting, where the shifter’s click is most prevalent, could I consistently and successfully shift how I wanted. However, I would still occasionally find myself missing a shift here and there. The ergonomics of the lever feel nice, but there’s a lot of throw required to push the lever in. The shifter works similar to SRAM’s double-tap road bike shifting system, where a small click/short shift drops down a gear, and a larger click/long shift goes back up.

Even with the shifter as firm as it goes, the feeling is sort of vague and takes a very long throw. This led to some rough shifts at times when I didn’t push quite far enough. The inability to shift more than one gear at once, coupled with the shifter’s long throw, makes for quite the thumb workout. Miss a shift and, at times, the chain would want to jump, usually down a large span of gears, but it would quickly find its way back to where it was supposed to go with another push. The only time this presented an issue was in slower, more technical terrain where that easier gear was crucial in cleaning a line on a climb.

The derailleur, which houses all of the shifting mechanisms in addition to standard derailleur duty, worked exactly as it should throughout the test period. The amount of tension on the cage felt a bit low at times, especially in rough terrain, as there was more noise and more chain slap than I’m used to with standard S products. That aside, everything held together through many miles on the trail and at the bike park, often in wet conditions. Even with frequent cleanings and hosings, nothing required extra maintenance or a bit of tuning up in a time I would typically replace a gear cable.

The 10-52 tooth spread, which has now been matched by SRAM’s new cassettes, provided plenty of range for steep climbs and fast descents. The jumps between gears are smaller than with a 12-speed cassette. It never felt as if I was over or underpowered – it was easy to find a comfortable spot with the gearing.


Pros

+ Lightweight
+ Low maintenance
+ 13-speeds, small gear jumps

Cons

Shifting is vague
Proprietary hub required for 13-speed cassette
Still not quite as smooth as high-end SRAM or Shimano


Pinkbike’s Take

bigquotes It’s fantastic to see brands pushing boundaries and bringing new products to market. Rotor’s hydraulic drivetrain is an excellent example of precisely that. The overall system works well, but at this price point, it should be outstanding. The shifting is accurate, and the hydraulic mechanism creates a system that requires minimal maintenance. However, it feels vaguer than it should, and it still isn’t as smooth as SRAM’s XX1 or Shimano’s XTR drivetrains. The proprietary hub doesn’t add any points either, as its engagement is fairly low compared to many other high-end offerings out there – something someone dropping serious money on a drivetrain is likely also looking for. Daniel Sapp

https://www.pinkbike.com/news/review-rotors-13-speed-hydraulic-drivetrain.html?trk=rss