Content
- Introduction
- What is Bosch eShift
- How does automatic shifting work on e-bikes?
- What is automatic downshifting
- What is wireless shifting
- What is RollShift
- Tern E-Bikes with Bosch eShift
- Rohloff E14 (GSD R14)
- 3X3 NINE (HSD S9i, HSD S9i Sport)
- TRP E.A.S.I. (HSD P10e, HSD P10e Sport)
- Comparison table
- Links
Shifting gears has always been part of riding a bike. As speeds change and terrain varies, riders shift gears to maintain a comfortable pedaling cadence. On a conventional bicycle, this is entirely the rider's responsibility, making it easy to stop at a traffic light in too high a gear or approach a hill without shifting early enough.
On an e-bike, the stakes are even higher. The motor adds significant power to every pedal stroke, so shifting while that power is still flowing through the drivetrain can result in harsh gear changes, increased drivetrain wear, and unnecessary stress on components.
What is Bosch eShift?
Bosch developed eShift to address these challenges. Rather than relying on mechanical shift cables, Bosch eShift sends electronic shift commands through the Bosch eBike system to the drivetrain. As the rider shifts, the drive unit briefly reduces motor assistance, allowing the next gear to engage smoothly before power is restored. The result is smoother, more precise shifting with less stress on drivetrain components and a more enjoyable riding experience.
Because shifting is fully electronic, Bosch eShift also delivers consistent performance over time without the cable stretch and periodic adjustments required by traditional mechanical systems.
That electronic coordination also enables new riding features. Depending on the drivetrain, Bosch eShift can automatically choose the right gear, shift down when the bike comes to a stop, let riders enjoy automatic gear changes while coasting, or replace traditional shift cables with wireless electronic controls. The exact features vary by drivetrain.
The following sections explain the major Bosch eShift features and the drivetrains that support them.
How does automatic shifting work on e-bikes?
Automatic shifting is one of the most advanced capabilities enabled by Bosch eShift. Instead of manually selecting gears, the system automatically shifts gears for you to maintain your preferred pedaling cadence.
Cadence is the speed at which you pedal, measured in revolutions per minute (rpm). Whether you prefer slower, more powerful pedal strokes or spinning at a faster pace, the system continuously selects the appropriate gear to keep you pedaling comfortably. Riders can always adjust their cadence setting based on the environment they are riding in via the bike’s control unit.
As you begin climbing a hill and your cadence slows, the system shifts to an easier gear. When the road levels out or turns downhill, it shifts into higher gears as your cadence increases. Throughout each gear change, Bosch eShift briefly reduces motor assistance so every shift feels smooth and seamless.
The result is a more relaxed ride, especially when navigating urban environments or hilly terrain, allowing riders to focus on the road ahead rather than thinking about when to make the next shift.
What is automatic downshifting?
Automatic downshifting is another Bosch eShift feature available on select internal gear hub (IGH) drivetrains. As you come to a stop, the system automatically downshifts into your preset starting gear, so you're ready to pedal away smoothly in an easier gear.
By ensuring you're always in the right gear to start, you eliminate one of the most common shifting mistakes: stopping in too high a gear. It's especially helpful in stop-and-go city riding and when carrying cargo or passengers.
What is wireless shifting?
Wireless shifting eliminates the cable between the shifter and the Bosch control system by using wireless technology, simplifying cockpit setup while creating a cleaner, more streamlined handlebar.
Wireless shifting also removes cables from the shifter to the control system, making maintenance easier and removing the need to replace the cables in the future.
What is RollShift?
RollShift allows riders to change gears while coasting, so they're already in the right gear when they begin pedaling again. Whether approaching a traffic light, corner, or hill, there's no need to wait until the pedals are turning to shift. On some Bosch eShift drivetrains, RollShift can even make these gear changes automatically.
Tern E-Bikes with Bosch eShift
Tern offers Bosch eShift with three different drivetrains: Rohloff E-14, 3X3 NINE, and TRP E.A.S.I. While all three use the Bosch eShift platform, each supports a different combination of eShift features.
Bosch eShift is available on the following Tern models:
- GSD R14: Rohloff E-14
- HSD S9i, HSD S9i Sport: 3X3 NINE
- HSD P10e, HSD P10e Sport: TRP E.A.S.I.
See the comparison chart below for a complete feature comparison.
Comparison table
| Tern Bike Model | GSD R14 (Gen 3) | HSD S9i / S9i Sport | HSD P10e / P10e Sport |
|---|---|---|---|
| Drivetrain | Rohloff E-14 | 3X3 NINE | TRP E.A.S.I. |
| Number of Gears | 14 | 9 | 10 |
| Gates Belt Drive | ✓ | ✓ | ✗ |
| Wireless Electronic Shifting | ✗ | ✓ | ✓ |
| Automatic Shifting (A) | ✓ | ✗ | ✓ |
| Manual Shifting (M) | ✓ | ✓ | ✓ |
| RollShift | ✓ | ✗ | ✗ |
| Automatic RollShift (M+) | ✓ | ✗ | ✗ |
| Auto Downshift | ✓ | ✓ | ✗ |
| Adjustable Cadence | ✓ | ✗ | ✓ |
| Adjustable Starting Gear | ✓ | ✓ | — |
Links
Learn more about customizing the eShift settings on your bike:
FAQ
- What kind of shifter is used mostly on e-bikes?
Most e-bikes use traditional mechanical shifters connected by cables. Premium e-bikes are increasingly adopting electronic shifting systems such as Bosch eShift, which coordinate the motor and drivetrain electronically to deliver smoother gear changes and enable advanced features like Automatic Shifting and Auto Downshift.
- Is Bosch eShift worth the money?
That depends on how and where you ride. Bosch eShift offers smoother, more consistent gear changes, reduces drivetrain wear, and can automate many of the shifting decisions riders normally make. For commuters, cargo bike riders, and anyone who rides in stop-and-go traffic or hilly areas, these benefits can make everyday riding noticeably easier and more enjoyable.
- What Tern e-bikes come with electronic shifting?
Tern currently offers Bosch eShift on selected models using three different drivetrains:
- GSD R14: Rohloff E-14
- HSD S9i, S9i Sport: 3X3 NINE
- HSD P10e, P10e Sport: TRP E.A.S.I.
Each drivetrain supports a different combination of Bosch eShift features, allowing riders to choose the system that best fits their riding style.
- What is the difference between Rohloff eShift, 3X3 NINE, and TRP E.A.S.I.?
Each Bosch eShift drivetrain offers a different riding experience.
- Rohloff E-14 combines a wide gear range with features such as Auto Downshift, RollShift, MultiShift, and Automatic Shifting (with the latest firmware).
- 3X3 NINE offers a wide-range internal gear hub with Wireless Electronic Shifting and Auto Downshift.
- TRP E.A.S.I. focuses on wireless, fully Automatic Shifting, making it an excellent choice for riders who want the bike to manage gear selection automatically.
