Shimano has announced two new Di2 electronic groupsets that can shift gear automatically based on rider speed and cadence, and can also shift (both manually and automatically) while the rider is coasting. The groupsets are e-bike specific and only work with new drive units which Shimano are also announcing today.
The all-new XT Di2 and CUES Di2 drivetrains have three shifting modes:
● Full Manual Shifting ● Full Manual Shifting with FREE SHIFT (which can shift manually while coasting) ● Automatic Shifting While Pedaling and While Coasting with AUTO SHIFT WITH MANUAL OVERRIDE (shifts automatically while pedalling or coasting, unless overridden by the rider)
Auto Shift is exactly what it sounds like - the system will shift for you as you pedal to keep you at the optimum cadence for the speed. It's basically an automatic gearbox for your e-bike. The manual override part should be fairly self-explanatory too; you can use the shifter to stop the computer from changing gear for you or to shift into a different gear at will.
Free Shift uses the e-bike motor to shift gears while coasting. The chainring can spin without you turning the cranks, so the derailleur can shift into a different gear during a descent. Of course, this only works while the bike is moving and the system won't power you forward without you pedalling. Combining this with the Auto Shift feature means the system can keep you in the right gear for the speed you're travelling without you having to pedal or touch the shifter, so in theory, whenever you decide to pedal the bike is already in the perfect gear.
The key to the system is the integration of the motor and drivetrain, which share the same battery and communicate via wires. Among other things, this ensures the motor turns the chainring at the right speed and at the right time for the derailleur to change gears properly. The cadence and speed sensors integral to any ebike drive unit make automatic shifting possible.
The system isn't wireless.
While the system isn't wireless like SRAM AXS, the derailleur shares the main e-bike battery's power so there's no external battery hanging off the derailleur and only one charging port to worry about.
XT Di2 will be offered in two tiers: XT Di2 HYPERGLIDE+ (12-speed with a 10-51t cassette) or XT Di2 LINKGLIDE (11-speed with an 11-50t cassette).
There will also be a lower-end Di2 e-bike drivetrain with similar features in 11- or 10-speed flavours called CUES Di2, which appears to be aimed at commuter bikes only.
Shimano Cues offers many of the same features at a lower price point but seems to be aimed at commuting and not e-MTB.
The new EP6 drive unit.
Motors and compatability
The XT and Cues Di2 drivetrains are not compatible with existing motors. Shimano have also developed the EP801 drive unit (an update on EP8 ) which can communicate with the Di2 derailleurs, along with a new EP6 motor which will offer similar features at a lower price point. Both motors provide 85Nm peak torque and a continuous 250 W output, but while the EP801 mootor weighs a claimed 2.7 Kg, the EP6 is 3 Kg.
Both are compatible with Shimano XT Di2 HYPERGLIDE+, XT Di2 LINKGLIDE, CUES Di2, internal Hub Gears Di2 specification and mechanical drivetrains. So in other words, the new motors will work with older Di2 or mechanical drivetrains, but the new Di2 drivetrains only work with the new motors.
Pricing & availability
Shimano say that XT Di2, CUES Di2, and EP6/EP801 drive units will be available on complete bikes from late spring / summer 2023.
As for pricing, Shimano says "these components will only be available as part of complete bike builds and therefore we do not plan to provide pricing for individual parts or groupsets at this time." We've also been told that we won't be able to get our hands on one until Spring 2023. Shimano is releasing this news early because some bikes will be seen at Eurobike with the system installed.