Choosing the best option for a drive train system won’t make you a better cyclist, but it can make the difference between having a great outing or a frustrating one. As with each part of the bike, there is a growing number of options in the drive-train category; our goal is to simplify your options so that you can spend more riding.
Most leading manufacturers have either privately or publicly acknowledged that electronic shifting will be the future standard; one day, mechanical shifting—like the rim brake—will be relegated to the same status as quill stems, threaded steering columns and toe clips—not entirely forgotten, but embraced by a minority.
But that time has not yet arrived, and there are still definable pros and cons to each. As with my comments regarding brake systems, these comments are based on considerations of premium and super premium level products only.
The key factors for consideration are:
- Over-all reliability
- Shifting Accuracy
- Shifting Speed
- Shifting technique
- Break-in period
- Maintenance & Upkeep
MECHANICAL VS ELECTRONIC
Simply, in mechanical shifting, the front and rear derailleurs are actuated by a steel cable that runs from the shifter/brake lever all the way to the derailleur. Each derailleur has springs to counter the tension from the cable. Over the years these systems have become increasingly dependable and accurate, which in turn enables faster shifts.
In electronic shifting, each derailleur has its own tiny batter-powered motor that moves the derailleur to the correct position. The motors receive their ‘orders’ from a signal that is transferred by wire or wirelessly coming from fingertip shift buttons/tabs. Batteries are located in a number of possible locations on or in the frame or on the derailleurs themselves.
Over-all performance and reliability.
The best systems of both categories provide great performance and are now very reliable. In all cases, the most frequent causes for a denigration of shifting performance are:
- Dirt accumulation in any of the moving parts including the chain;
- Cumulative wear or damage to gear teeth;
- Repositioning of the rear wheel (as in after changing the tire).
- Shifting accuracy and speed.
- Both categories, within reasonable debate, are now equally fast and accurate.
It used to be that in the same way when you’d learn to drive a manual shift auto transmission a cyclist had to develop some finesse, a touch, for both when to shift and how to shift, feeling for the right amount of shifter adjustment, letting up on the force placed on the pedals to obtain a smooth and relatively quiet shift. Because the accuracy and speed have improved and shift positions are noted in clicks with either system, less planning is required and the systems better tolerate shifting while pedaling ‘normally’. In short, any idiot can accomplish shifting today with either mechanical or electronic shifting, however, a little finesse, as in a momentary let up in pedal pressure, insures a quieter shift while significantly reducing wear on the system.
Since an electronic signal (not a moving cable) initiates a shift by a button, the shift buttons can be placed anywhere or in multiple locations on your handlebars. With a mechanical system, the shifting will be in your brake levers (unless you have a TT/TRI specific bike).
Where electronic shifting really begins to separate itself from tradition is in its future potential. In time, when coupled with a power meter crank, users will be able to program shifting from a computer, tablet or smartphone to automatically shift based on power, cadence, heart-rate, etc. And for those who are total information junkies, the options for collecting and sharing data is endless.
The cables in a mechanical shifting system are pre-stretched, yet, will generally stretch a small amount more in the first hundred or so shifts at which time you’ll find the shifting is not quite as fast or smooth. For this reason, mechanical system derailleurs have thumb adjusters that with a small turn will reset the cable tension and can be easily handled by the DIY cyclist. Electronic shifting has no break-in period.
Maintenance and Upkeep
- As previously mentioned all components must be kept clean and lubricated for trouble-free performance.
- Mechanical shifting cables also need to be kept free of dirt and corrosion and lightly lubricated.
- Electronic systems require the battery/batteries to be periodically charged and eventually replaced.
You are alone in the middle of nowhere with only a small toolkit and your derailleurs stop working. The simplicity of mechanical shifting makes emergency service both less likely and more manageable. Of course if there is a major part failure, you may be screwed with any system. But if everything is still together and it’s simply a functional issue, a mechanical system is more serviceable to the resourceful cyclist. Worst case scenario is usually the result of either a shifter or cable failure. As remedy, you can choose one gear combination and adjust the derailleurs to stay in that position.
If you have electronic shifting you’d better hope that you were not in top gear when the system decided to check out. There are more potential things to go wrong that even a competent DIY’r won’t be able to handle on the road/trail like servomotors, button actuators, batteries and wires.
It goes without saying that you have to remember to charge your batteries periodically or carry a spare.
Wireless Electronic systems, which at the moment is limited to the SRAM Etap does have some clear advantages over the current Shimano and Campagnolo electronic offerings. First, there are no wires. Not from the shifter to the derailleurs, nor from the battery to the shifters or derailleurs- no wires that could get worn, cut, damaged, shorted at connection points, etc. Another key benefit of the Etap system is that each derailleur has its own battery. They are small and interchangeable, so if your rear derailleur battery dies, you can always swap it with your front battery and still have a good range of gearing. Or, you can carry a spare is conveniently small, light and easy to install.
From a design perspective
Any responsible frame builder will have an aversion to drilling holes in tubes of any material. No matter what the builder may do, it creates a potential weak area or place of entry for substances you really don’t want inside your frame/fork. So whether mechanical or electronic, external routing is preferable. It is also much simpler and faster to assemble, disassemble, reassemble inspect and repair the bike. This is why Serotta Design Studios prefers the SRAM Etap electronic systems. No wires or cables (other than brake). No holes, super clean look.
Mechanical Shifting is your choice if
- You are managing your budget closely;
- You want a little freedom from batteries, electronics and connectivity;
- You are forgetful;
- You are less diligent about maintenance but don’t mind having to tweak adjustments from time to time;
- You ride this bike through sub-freezing weather for several months a year;
- Absolute minimum weight is high on your list;
- You don’t need to feel you are with the most current trend.
Electronic Shifting is your choice if
- You value fractions of a second difference in shift time;
- You embrace the future trend;
Ben's personal component preference? Ben enjoys bikes that are set up both ways. However, if limited to only own one road bike, his would have wireless electronic shifting. It works great, and it's easy to love the super clean look without cables or wires.