First shown last Sea Otter, the Rotor 1×13 hydraulic shifting mountain bike group is finally in production and shipping soon. Not interested in switching away from SRAM or Shimano? There’s still something here for you. They’re also offering a 1×12 group, which has the benefit of using a standard Shimano HG freehub body. And with an 11-52 cassette, you barely lose any range over the latest 12-speed groups from the big boys. What you do lose, though, is weight, and a good bit of it…

Rotor 1x13 ultralight mountain bike drivetrain that shifts hydraulically

Let’s start with the mix and match options, then we’ll get into the full group. If you like the idea of a lightweight hydraulic shifting group, you could run their shifter and derailleur with a SRAM Eagle cassette. Or, if you like SRAM Eagle shifter and derailleur, the spacing is the same on Rotor’s 12-speed cassette on a SRAM Eagle drivetrain. So, you could drop a about 30g if you’re running the biggest cassette. Or you could save a lot more if you’re looking for less range and tighter gear steps…here’s all the weights:

claimed actual weights for rotor 1x13 hydraulic mountain bike group

Rotor 1x13 ultralight mountain bike drivetrain that shifts hydraulically

If you want the maximum range, you’ll need to go with their 1×13 setup, which means using their rear hub. Why? Because while it uses a standard HG freehub, the hubshell is slightly narrower because the 10-tooth cog hangs off the end of the freehub, and the axles are reworked to fit in Boost frames. For U.S. customers, you can have Rotor get a custom rear wheel made through with various rims.

Rotor 1x13 ultralight mountain bike drivetrain that shifts hydraulically

The shifting is a closed system, which has been finalized over an open system they were considering when we saw the group in April. Technically, this means it has a nearly infinite service life since contaminants can’t enter the system, but they recommend annual bleeds and fills just to be safe.

Rotor 1x13 ultralight mountain bike drivetrain that shifts hydraulically

The lever looks like a dual system like most other brands, but in fact is just a single push-or-push-further design. Push it a little bit to release, and push further to “pull” the derailleur onto a larger (easier) cog. The smaller secondary lever is there as an alternate thumb position that’s easier to reach when you’re way back off the saddle during aggressive descents.

Rotor 1x13 ultralight mountain bike drivetrain that shifts hydraulically

The back side has a reach adjust screw that lets you set the starting position for the shift lever. Retail prices are $999 for the shifter and derailleur alone, or €2,549 / £2,399 / $2,899 (Performance Kit), €1,799 / £1,699 / $2,099 (Super Light Kit) and €1,399 / £1,299 / $1,599 (Mountain Ready Kit). Check out our Sea Otter coverage for additional details and video.

Rotor InSpider universal power meter

Rotor InSpider power meter for road gravel cyclocross and mountain bikes

Thus far, Rotor has offered their InPower spindle-based power meter, which could be mixed and matched with strain gauges inside the drive side crank arm. This gave you the option of measuring left, right, or both. The new InSpider offers a third option and sits between the two in price.

Rotor InSpider power meter for road gravel cyclocross and mountain bikes

Since it’s only on one side, it offers virtual left side power, but has some interesting tech that helps it compensate for temperature and other fluctuations. The system uto calibrates in real time, so there are no gaps in your data (they say some spider-based power meters need will periodically restart to re-calibrate themselves mid-ride).

Rotor InSpider power meter for triathlon cranksets

Aero crown available for triathlon chainrings, and the design can be put on any of their current direct-mount road or mountain bike cranksets, with 1x or 2x chainrings.

Rotor InSpider power meter for mountain bikes

Claimed weight for the spider is 149g, which allows them to build up the lightest (their claim) Power Meter MTB crankset at 506g with their Kapic Carbon. 

Works with Super Boost, Boost and “original” mountain bike frames, but the inside does stick out slightly, so you’ll want to check around the BB area to make sure there’s adequate clearance.

Rotor InSpider power meter for road gravel cyclocross and mountain bikes

It’s rechargeable using a magnetic connection. They rate it at 225 hours of run time with a three hour full recharge time.

Retail is $649 for the spider, plus whichever crankset you want to put it on.


  1. emailphiliprowegmailcom on

    Rides in direct sun, fluid expands….adjusts shifting. Clouds come out, readjust shifting….keeps riding. Single speeds sounds so good.

    • Greg on

      Considering how that didn’t happen with Magura rim brakes (or any other closed hydraulic systems), I doubt it’s an issue. It takes quite a bit of heat to make an impact. And the plastic lines are decent insulators.

    • Rodrigo Diaz on

      I was curious, then checked the expansion coefficient for mineral oil (proxy for paraffin oil)

      Volumetric Thermal Coefficient: 0.000764 / C

      You’d need about 65 Celsius difference to make a 5% difference. I ride a fat bike in the winter and would find it I can barely get to that range at the highest and lowest temperatures I ride.

      • Bob Log on

        65 Celsius temp difference is rather wide – that’s roughly -20F to 100F.
        I’d be more worried about viscosity differences at the lower end of that temp range. Of course, it’d be hard to tell the difference with -20F fingers.

  2. Tim on

    I find it funny how a strong majority of people think that hydraulic brakes are the only brakes that you can ride on a real bike, but that those same people think that there’s no way hydraulic shifting can possibly work.

  3. Tim on

    Still, hydraulic shifting is likely to be inferior to electronic shifting. With hydraulic shifting, you’re still using your thumb to force a column of fluid to push a derailleur to push against laterally stiff chain and lift it up onto a taller cog. With electronic shifting, you just push a button that sends a signal, and then the derailleur does all the work for you.

      • roadstain on

        I -could- have afforded any shifting system on earth for my main road bike. I ended up with Record12 cable… reason to over complicate things. The only potential change would be wireless, I still depend on batteries however. I know that during the ‘end days’ my bike will be fine and shift even when the grid goes down for ever….

  4. Mikey on

    Nice weights on those 12 speed cassettes! Good option for those who want to run 1×12 and have a set of wheels with the Shimano freehub body they can’t or don’t want to change to XD.

  5. Yoni on

    Yes. Very nice indeed. I’ll just call my banker to cancel the yacht I ordered the other day so I could have this, while I wait for the ‘driven’.


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