Should your next groupset be electronic?
At the top end of the bicycle market, you’ll now almost always find bikes kitted out with electronic groupsets. Every pro team uses electronic shifting. Although the tech remains stubbornly expensive, that’s now showing signs of changing. So what are the advantages of electronic shifting?
Swapping from a mechanical to an electronic groupset, the first thing you’ll notice is the precision of the shifting. It’s pretty good in a well set up cable-operated system, but just feels that much snappier when it’s carried out by motors.
Whereas cable stretch and contamination can degrade mechanical shift performance over time, with an electronic groupset this just doesn’t happen. That makes it a good option for winter conditions, if you want to ride your best bike all year.
It’s also an advantage for cyclocross and gravel, although if you do wreck an electronic rear mech the replacement price is pretty frightening. There is a mechanism built in to disengage the derailleur cage from the motor though, which is designed to reduce the chance of damage.
Modern road bikes, like our range here at Pearson, are now increasingly integrated and feature hidden cable runs from the levers into the frame. There’s a significant aerodynamic benefit from internal cabling and it looks really sleek too. Integrated designs can usually accommodate mechanical cables, although some brands have designed frames that are specifically designed for electronic groupsets.
However, the tight bends needed to run cables into the stem and from there into the headset can add friction in mechanical set-ups, so they can require more TLC. That’s not an issue with electronic groupsets or with hydraulic disc brakes though.
Electronic shifting is faster than mechanical too and you can configure multi-shifts that let you shift over multiple sprockets just by holding the shift lever down, rather than having to make multiple jumps or a huge lateral movement of the shift lever.
In SRAM systems, shifting is more intuitive too: hit the right shift lever to move to higher gears, the left one to move to lower ratios and both together to switch between chainrings, either up or down. That makes for easier shifting, particularly if you’re wearing heavy gloves. Shimano’s shift paddles are quite close together, so it’s easier to mis-shift although the latest 12-speed system has sought to address this, but Campagnolo has its usual thumb shifters on the inside of the lever bodies, which avoids this problem.
Electronic systems will self-trim the front mech too, so that as you move up or down the cassette chain rub is a thing of the past (SRAM’s yaw parallelogram avoids the need to self-trim). If you do need to realign the mechs, this is done electronically, rather than requiring you to go at them with an Allen key.
Electronic systems will give you lots of usage stats too, like how often you’ve shifted gears during a ride and your most-used ratios. It might not be very useful, but it’s fun to know.
Although you can exhaust batteries, it’s not too difficult to keep them topped up. Shimano and Campagnolo systems have high capacity internal batteries that will keep going for ages. Even SRAM’s batteries will power its mechs for up to 60 hours and all the systems let you check charge level and warn you if it’s getting low. You can continue to ride, albeit with lower functionality, if you do run out of charge., so you should always be able to get home. Recharging is quick too.
Weight-wise there’s not a lot in it between electronic and equivalent level mechanical groupsets. Whereas the batteries and motors add weight to an electronic system, wires are lighter than cables and there are fewer, lighter components inside the shifters.
Novel shifting options
Electronic shifting isn’t just about doing the same thing better though - it opens up new options in how to set your bike up. Whereas cable-operated shifting is constrained to “push this lever to shift one way, push that one to shift the other way”, electronic shifting is a lot more versatile.
All the electronic groupsets let you configure your controls how you like, so you can for example set the left shifter up to change your gears at the rear. More useful are the synchronised and semi-synchronised shift options (SRAM calls these sequential and compensating).
Set the system to synchronised shifting and you can just hit one lever to shift up and another to shift down. Once you get to a set point on the cassette, the system will automatically trigger a front shift and a compensating rear shift to get you the next available ratio up or down.
That’s useful, although the change can be a bit rough as you’re not always aware that the front shift is coming, so you may not ease off as you would with a user-initiated front shift.
In semi-synchronised shifting mode, when you change chainrings the rear mech will shift up or down a user-configured number of sprockets automatically, so you’re not left spinning too high or low a gear.
Since you’re not using a couple of the shift levers, Shimano lets you programme them to control a bike computer. There are additional buttons built into all the brands’ levers which can be programmed to do this or perform other functions and many bike computers can be set up to display which gear ratios you’re using.
Want to shift more easily with your hands on the tops or in the drops or on TT extensions? Both Shimano and SRAM let you fit satellite shift buttons to do this.
Electronic shifting: what are your options?
The big three road bike groupset makers, Shimano, SRAM and Campagnolo, all offer electronic groupsets and FSA has got into the act too with its WE groupset.
Shimano’s Di2 system is the most prevalent electronic option. You can buy its electronic groupsets in Dura-Ace Di2 and Ultegra Di2 specs for road or GRX 815 Di2 for gravel bikes. There’s also a Di2 Alfine hub gear for city bikes and a range of MTB options.
Shimano has just launched its latest 12-speed Dura-Ace and Ultegra Di2. These use an internal battery to power the derailleurs, which is usually housed in the seatpost and is recharged via a port in the rear derailleur. There’s a wireless link to the shifters, although you can also wire these into the system. They’re powered by coin cells that Shimano says will last for up to two years before needing to be replaced.
There’s now built-in Bluetooth that lets you programme the groupset using Shimano’s e-Tube phone app. As well as 12 speeds, both Dura-Ace Di2 and Ultegra Di2 now offer a power meter option. Mechanical Dura-Ace and Ultegra have been discontinued, but you’ll still be able to buy a Dura-Ace Di2 rim brake groupset, although there’s no wireless shifter option - it needs to be wired.
Whereas Dura-Ace Di2 is super-light and super-expensive, Ultegra Di2 and GRX Di2 temper that somewhat by using less flashy motors and materials.
SRAM went one up on Shimano with its original 11-speed Red eTap, when it offered wireless electronic shifting instead of a wired system. This makes set-up a lot easier as there’s no internal wiring to sort out and there’s no risk of dirt or wet degrading cables either.
It’s stayed ahead with its latest eTap AXS system too, by offering cassettes with 10-tooth smallest sprockets whereas Shimano has stuck with 11 teeth. These allow it to provide the same top-end ratios but with smaller chainrings, while the widest range cassettes go up to 36 teeth, for an extra-low lowest ratio.
eTap AXS is available as the premium Red eTap AXS and at Force level. SRAM has kept the pressure on by launching Rival eTap AXS too. This uses the same electronics as SRAM’s higher priced eTap groupsets, but cheaper materials like a steel front derailleur cage, while you can’t run satellite shifters. Its full retail price of just over £1000 significantly undercuts Shimano Ultegra Di2.
In addition, you can use road eTap groupsets with the Eagle eTap AXS MTB rear mech in a so-called mullet build, to give you a single ring set-up with a 10-52 cassette for gravel riding. There are also Force and Rival eTap AXS Wide options, which give extra clearance for gravel bike tyres and even smaller chainrings for lower gearing.
Each derailleur has its own battery, which you unclip to recharge on the USB charging unit. The shifters are powered by non-rechargeable coin cells. Although battery life is less than Shimano Di2, there’s plenty of capacity for multiple rides between charges and you can swap the front and rear derailleur batteries if you do find the rear mech’s battery is running down.
eTap AXS has WiFi functionality built in, which makes it easily configurable via the AXS phone app, which also lets you check battery charge level.
A few years ago, Campag offered its EPS electronic groupsets at Super Record, Record and Chorus level, but it’s now retreated to just sell Super Record EPS, making it a super-expensive option.
It’s a wired system with 12 speeds and an internal battery with, like Shimano, the junction unit usually housed in the bar end. There’s also Bluetooth comms with a phone, to allow configuration via the MyCampy app.
Read our guide to Shimano road and gravel groupsets here >