Friday, August 28, 2015

Hydraulic Shifting? Why?

Cables are too simple for some people. Light. Simple. Easy to understand. Easy to fix. Replacing a damaged cable, whether for brakes or shifters, is an easy job even for an inexperienced home mechanic.

Can't have that, can we?

Even now, as hypesters are trying to convince us all that the future is electronic shifting (and that future is NOW!), oval chainring maker ROTOR Bike Components is releasing a new different technology -- hydraulic action shifting, to complement hydraulic brakes.

"Hydraulic systems are already something we use everyday without thinking twice," said Carlos Cartรณn, the lead engineer, "in car brakes, construction equipment, and airplanes. So it made sense to apply this proven technology to bicycle transmission, where the advantages are really clear."

Well - yeah. Hydraulic systems on cars and airplanes -- given their size, complexity, power, etc. -- are clearly superior to cable-actuated systems. But bikes aren't cars, or airplanes. Bikes are small, light, and simple. Cables work fine, and I fail to see how the "advantages are clear."

Dubbed "Uno," the system uses hydraulics to work both of the derailleurs as well as the brakes. Their brake technology was developed with help from Magura, but the derailleurs are unique tech. The company claims that hydraulic actuation will bring "increased precision" over cable-actuated systems, without the "disadvantages . . . like friction, devolving inconsistent force over time, and other inconveniences."

I don't know -- the "disadvantages" of a cable system, to my mind, are well offset by the simplicity. And cables themselves have actually improved to the point that the old notion of cable stretch is practically a non-issue. In fact, it was never considered a problem until the advent of indexed shifting -- in the days of friction-only shifting, who even noticed that the cables stretched over time?

But the folks at Bicycling tout the system's possible benefits: "less maintenance and better precision - at a lighter weight and with less complexity."

Hydraulic pistons, rack and pinion mechanisms, hydraulic lines, master cylinders and slave cylinders. . . Yeah, that looks a lot less complex.
Lighter weight? Lighter than an electronic system with its batteries, etc., but I have a hard time believing that it saves any weight over a traditional cable system.

Less maintenance? Maybe so. But then again, have you ever bled a hydraulic system? I've done it on both cars and motorcycles, and it's a P-I-T-A. Messy. Finicky. And I admit that I don't know for sure what kind of hydraulic fluid they'd be using, but most types of hydraulic brake fluids have a limited shelf life once they've been opened. And for home mechanics who would only be doing such work occasionally, that means waste. Not to mention that old brake fluid is a contaminant that really shouldn't be disposed of by pouring it down the drain -- it needs to be recycled properly.

A unique aspect to the Uno derailleurs is that, unlike indexing systems from Shimano, Campagnolo, and SRAM, the indexing mechanism is built into the derailleur instead of the lever. That kind of reminds me of the old Shimano Positron system, or even Huret Commander -- both of which had the indexing in the derailleur. Neither was very successful. It's possible that having such a system actuated by hydraulics instead of cables would work better than on those early indexing shifters, but I'm not going to be putting that to the test.

More info will come about the Uno hydraulic shifting system soon, since Eurobike is currently underway.


  1. Thankfully I have very good friction shifters that will last longer than I will.They shift quickly and accurately every time. I feel very sorry for folks who are so uncoordinated that they can't operate them.

  2. If everyone rode a single speed, then we would not need all the fancy shifting technology at all. Old is good.

  3. In fairness, some hydraulic brakes use mineral oil instead of brake fluid.

    1. You are right - that's definitely true. Like I said, I don't know what kind of fluid this particular system will be recommending. Mineral oil reportedly has a longer shelf life. I'm unfamiliar with disposal recommendations. Boiling points for mineral oil brake fluids seem to vary by maker -- which can be a possible problem for disc brakes if it starts to boil under hard braking. Still messy and a P-I-T-A to replace, bleed, and clean up though.

  4. We need this like we needed electronic shifting.

  5. It's all very well having precision shifting, but what about the times you don't want precision? I run a friction shifter on my front derailleur because it allows infinitely adjustable trimming. Have these designers never experienced chain rub?

  6. Amen, brother. They'll have to take these cables from my cold, dead, hands.

  7. The only justification for hydraulics is where a high amount of force is required at the end point, such as in the case of disk brakes. With properly designed mechanisms, no such force should be needed to shift gears. It's probably just something that's designed for electronic control, which depends on a functioning battery. And we saw how well that worked in the Tour de France.

  8. The poor pike shop mechanics... before long, they're going to have to be engineers to sort out a repair job on all of this silliness coming to bikes.


  9. I have one (MTB) bicycle with hydraulic brakes and that's plenty. I was in a bike workshop last year when a guy brought in a bike to have the brakes bled. Two pro mechs (both long experienced) took over an hour before giving up.

    I've done it on motorcycles and cars (including hydraulic clutches) but as you can see from the various syringes and plungers on offer from Avid and the like, bicycles are even harder. Now you can buy new brake "systems" that come in one piece lever/hose/calliper. I suppose the idea is you just check everything instead of bleeding.

    From science class I remember that all fluids are incompressible. Brake fluids are hygroscopic - they absorb water into solution so that heat "boiling" the fluid does not result in total loss of braking (BT, DT). I don't think this is really an issue in bicycle brakes (heat problems are more with the pad/rotor interface) but DOT brake fluid is pretty aggressive stuff. No doubt mineral oil is more benign and works just as well.

    Hydraulic brakes are nice, but not *that* nice. And shifting? Crazy

  10. Agree this is a solution in search of a problem. All the same, I'd rather have consumers hard earned cash going to bike manufacturers rather than car companies!