At this point in the technological history of mountain biking we currently have hydraulic disc and rim brakes, hydraulic fork lock outs, and hydraulic dropper seat posts, so why not hydraulic shifting? That seems to be what Acros is thinking as they are reincarnating Christophe Muthers’ 5-Rot hydraulic shifting system that was first debuted at Eurobike in 2006.

I remember seeing photos of the system, wondering how well it would work, but sadly, the concept never made it to production. Until now.

Acros has picked up the design and made a few necessary changes to make it broadly compatible with today’s mountain bike drivetrains. The first run of production will be extremely limited, as Acros is only planning to manufacture 250 complete sets world wide, which surprisingly are all ready starting to be pre-sold despite the nearly $2000 price tag here in the US.

Check out the A-GE system details, pricing, and whether or not you can find a set after the break!

While the mechanics of the system haven’t changed, Acros had to create some improved shifter mounts to ensure that the shifter position would offer enough adjustment regardless of how one would set up their controls. Also, now Acros offers the ability to integrate the shift lever with popular brake levers as well.

Shifting the A-GE system is accomplished by pushing the lever forward, which allows up to 3 shifts in either direction. Pushing the bottom of the shift lever changes the oil flow, which changes the shifting direction.

While it is common practice today for rear derailleurs to use a slanted parallelogram design, in the Acros system, both derailleurs utilize the design, which results in a very compact, yet stiff front derailleur. The rear derailleur will be offered in both long cage and mid cage versions for the first run of production. In addition to the cages, you can also change out the Raster Rod which provides shifting feedback, but also is available in 8, 9, and 10 speed versions.

In order to connect the hydraulic system, both derailleurs have two minuscule hydraulic lines attached which allow the flow of oil to move the derailleur.  If you notice, there seems to be a lot of tiny connectors, which would make for a lot of separate parts, and you would be right considering there are an incredible 248 parts that make up the entire system! That’s not to say it’s not light though, and considering the fact that the shifter is only 65g, it’s not hard to believe that the A-GE system comes in at 150-175g lighter than it’s closest mechanical competition.

So why even bother with a hydraulic system in the first place? For starters, the A-GE system promises silky smooth shifting, which will stay that way. Without cables and housing to deteriorate over time, the shifting quality of the hydraulic system shouldn’t change. Keep in mind, that a shifting system will not experience the heat cycles like a disc brake would, so barring catastrophic failure the sealed system should remain at peak performance for a long period of time, if not indefinitely. Clearly, the price will keep the majority of the market from experiencing hydraulic shifting first hand, but like any good technology if it works there will undoubtedly be some trickle down to a more attainable price.


  1. We are going to buy this company and make it our own, for the next road/mtn/cx group you all want to run with your CX hydro disc brakes.

    The name of this group: BLOOD.

    Get it? It’s fluid AND red: BLOOD

    You heard it here first.

  2. I could see this being the future of MTB shifting, makes more sense to me than electronic systems. Now I just gotta wait for it trickle down to XT level pricing.

  3. @John

    Cables stretch and housing compresses over time. This is why new bikes need a tune up relatively early.

  4. Sorry, Zach. Hydraulic Shifting was introduced way earlier. I remember a guy named Jochen Wendler has introduced a system in 1995. I think it was at Eurobike 1995. It was also published in bike-magazine.
    See following link

    I don’t know, when you were born, but a little bit of research would be fine before writing about history.

  5. i dont know about this
    while i am handy enough with my bike to bleed to brakes this looks like it could be a lot harder for someone to adjust on their own. I think electric, while you need to replace parts, is still a better option as far as not needing maintenance. I mean for electric you just plug in new wires, this i could see bleeding being tough to do. But i do think it is a step in the right direction as far as non-cabled drive trains but i think routing will need to improve to see any advantage for this stuff.

  6. The primary advantage of hydraulics in brakes is that you can vary piston sizes to have very high forces or long travel, and due to the miniscule stiction you can due very fine modulation in force with little to no actual motion of the pistons. Neither of these are important for shifters- particularly modern indexed shifters.

    I’m sure they feel very smooth- I just don’t really see a performance advantage. Sure- the cables won’t degrad over time, but air will eventually enter the system. With brakes, you can just squeeze harder or pump the brakes. Not an option for a shifter. Hopefully there’s an easy way to make adjustments around that, because it’d be bad to have to bleed your shifters all the time to avoid ghost-shifting.

  7. A big advantage of hydraulic over electric that nobody is talking about is that hydraulic can survive a EMP so we can keep on riding if a post-apocalyptic future were to come to pass!

  8. @ mcaad:
    Zach never wrote it was the first, only that this particular system was first shown in 2006.

    I don’t know when you were born, but a little bit of reading would be fine before writing about others.

  9. I like the concept but the shifter it just ripe for mis-shifts, IMO. If they’d used a twist shifter (like mcaad’s link above), the system would probably be lighter, simpler and require less thought.

  10. This is the most wonderful bit of shifting porn since Airlines, and it seems as equally unnecessary as that system was. It is, however, completely badass-looking and clearly took tons of machine hours to CNC each part. If nothing else I want a set of these for the novelty of it all and the beautiful machine work.

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