Introduction to the Tern Vektron Folding eBike with Bosch eBike System 2

Tern Vektron Gen 4 Folding Electric Bike with Bosch eBike System 2: The Basics

This article refers to Vektron Gen 4 folding ebikes with the Bosch eBike System 2. Click here if you have a Vektron Gen 4 with the Bosch Smart System.

Thank you for choosing Tern, and congratulations on your all-new Vektron! We're excited to join you on your many journeys. We want to make it easy for you to hit the road as soon as possible, so we’ve prepared this guide to help you every step of the way. But if you prefer a video walkthrough, take the time to watch our Owner Briefing on YouTube.

Let’s get started!

Contents

1. Introducing the Vektron Gen 4

2. Adjusting the bike fit

3. Bosch eBike System 2

4. Changing gears

5. Brakes

6. Folding, rolling, & parking

7. Max Gross Vehicle Weight

8. Daily riding checklist

9. Ready for the ride?

 

1. Introducing the Vektron Gen 4

Riders of the Tern Vektron Gen 4 enjoy a refined folding electric bike that pairs the Bosch eBike System 2 with Tern’s patented frame and fold. Balancing portability with confident handling, it delivers smooth, reliable pedal assist for commuting, travel, or daily use. Now in its 4th generation, the Vektron adds thoughtful upgrades—including the highly requested Gates Belt Drive—for a dependable ride that’s easy to take anywhere.

2. Adjusting the bike fit

2.1 Adjusting the saddle height

Open the quick-release levers on the seatpost to adjust the Vektron’s saddle height. Be sure not to go beyond the minimum insertion markings on the tube, as doing so may compromise safety and stability.

Start by adjusting the top section, then move to the bottom. Once you’ve found the right height for you, secure the levers tightly. If you notice that the seat is shifting a bit after securing the quick-release lever, it’s possible that the clamp is not tight enough. Turn the clamp’s screw nut to tighten it, and you’re good to go.
 

2.2 Adjusting the Andros Stem

The Vektron features an Andros Stem, which lets you easily adjust the handlebar position for optimal comfort. To use it, open one lever at a time, set the stem and handlebars to your preferred position, then close both levers securely.

3. Bosch eBike System 2

The Vektron folding electric bikes with the Bosch eBike System 2 include these models: P5i, P8i, and P10.

The Vektron is a pedelec

Before you go out and about on your Vektron, we’d like to remind you that the Vektron is a pedal-assisted electric bicycle—pedelec for short. This means that the Bosch motor will only provide power while you pedal. The motor will stop providing power once you have reached the speed limit set by your local authority.

 

3.1 Display and controller

The P5i and P8i Vektron folding ebikes with the Bosch eBike System 2 have the Intuvia display, whereas the P10 has the Purion display. Below is an overview of their main features.
 

 

Purion (P10)

Intuvia (P5i, P8i)

Power on/off button location

On top of the display

Bottom left of the screen

Assist Levels

Eco, Tour, Sport, and Turbo

On both displays, toggle the (+) and (—) buttons to switch between the assist levels

Ride Stats access (distance, range, etc.)

Press and hold the (—) button

Press the (i) button on the controller

Notes

  • In all cases, remember to keep your feet off the pedals when turning on the system to prevent unexpected acceleration.
  • The Intuvia display can be removed from its mount by pressing the tab on the back and sliding it off. The Purion display is not removable.

3.2 Lighting system

The Vektron comes with front and rear lights installed. To turn them on:

  • Intuvia: Press the button with the light icon.
  • Purion: Press and hold the (+) button.

A light icon will appear on the display, indicating the lights are active. Also, ensure the switch on the light itself is toggled to the right.
 

Reminder

To activate the lights using the LED Remote button, ensure the switch is in the "on" position. If you prefer to use only the rear light, slide the front light switch to "off."

3.3 Battery and charging

Your Vektron includes a Bosch e-bike battery and charger. To install the battery, slide it into the battery mount and push it down until you hear a click. The click means that the battery is locked in place. You can charge your battery either on or off the bike. In all cases, ensure the system is turned off before charging, and there’s no moisture around the socket area.

Charging the battery ON the bike:

  1. Locate the charging port on the Vektron’s drive side.
  2. Lift the rubber tab and plug the charger into the bike before plugging it into an electrical outlet.

Charging the battery OFF the bike:

  1. Remove the battery from the bike by inserting and turning the key in the lock to release the battery.
  2. Lift the battery out of the mount, and plug the charger into the battery. The lights on the battery itself will indicate the charge level.
     

3.4 Keys and frame lock

The Vektron P5i and P8i with the Bosch eBike System 2 have a built-in frame lock that’s keyed alike with the battery.

The key stays in the frame lock after unlocking and while riding, so it’s always easy to find and won’t get lost. To lock the frame lock, turn the key and slide the knob down until you hear a click. You can remove the key once you hear the click. If the lock isn’t fully engaged, you won’t be able to remove the key.

Your bike comes with identical keys to unlock both the battery and the frame lock. For safekeeping, we recommend emailing the key number to yourself and registering your keys with the lock manufacturer. They will need the key number to order the replacement key for you. In addition, when you sign up for Tern Care, we recommend entering your key number as part of the registration process.
 

3.5 Walk Assist

When pushing your Vektron uphill, you can use Walk Assist, a feature that gives the motor a bit of a boost. Before you use Walk Assist, ensure your bike is in one of the four assist levels. Walk Assist will not activate if the motor system is set to "Off." This is how you use it:

Intuvia (P5i, P8i)

Purion (P10)

  1. Press the “Walk” button once, located on the top edge of the Intuvia controller (left side of the handlebars).
  2. "WALK+" will appear on the screen.
  3. While "WALK+" is shown, press and hold the (+) button to activate Walk Assist.
  4. Walk Assist turns off as soon as you release the (+) button.
  1. Press the “Walk” button on the bottom side of the display.
  2. "WALK+" will appear on the screen.
  3. Immediately press and hold the (+) button for 3 seconds to activate Walk Assist.
  4. Keep holding the (+) button to continue using Walk Assist, and release it to turn it off.

 

4. Changing gears

The Vektron folding ebike comes with shifters that help you modify pedaling resistance. The shifting mechanism varies depending on your bike model.

4.1 Trigger shifter (P10)

The P10 has a trigger shifter. Push the shifter levers to change to a higher or lower gear. The indicator will tell you which gear you’re in. The lower the gear, the lighter the pedaling. The higher the gear, the harder the pedaling.

4.2 Twister shifter (P5i, P8i)

The P5i and P8i have a twist shifter. Twist the shifter forward and backward to change gears. The lower the number, the lighter the pedaling. The higher the number, the heavier the pedaling.

4.3 Internally geared hub

The “i” in your bike model’s name indicates that your Tern Vektron has an internally geared hub. The benefit of having an internal hub is that you can shift gears at a standstill, which is helpful in case you forgot to downshift before stopping at a traffic light. However, internal hubs are not designed for shifting under load, so be sure to stop pedaling when shifting gears.

We highly recommend shifting gears as you would on a non-electric bike: downshift when stopping or climbing a hill, and upshift when accelerating or going downhill. This keeps your cadence smooth and helps prevent premature wear on the drivetrain.

5. Brakes

The Tern Vektron is equipped with hydraulic disc brakes on both the front and rear, providing strong and reliable stopping power.

Seen from the rider’s position, the right lever controls the rear brake, and the left lever controls the front brake. In some countries, this setup may be reversed, so check before your first ride if you’re unsure.

Brake pads are consumable parts and will need replacing over time. Their lifespan will depend on factors like how often you ride and how much weight you're carrying, so be sure to keep an eye on their condition.

6. Folding, rolling, and parking

6.1 How to fold the Vektron

  1. Remove any accessories from the bike that may hinder folding.
  2. Rotate the crank arm until the left pedal points downward at a 45-degree angle.
  3. Lower the saddle completely, and turn it slightly counterclockwise.
  4. Adjust the Andros Stem so that it faces upward.
  5. Disengage the kickstand and unlock the OCL+ frame joint by pushing the red latch, and lift the lever.
  6. Hold the handlebars and pull the front of the bike back. Make sure that the magnet on the fork engages with the rear magnet.
  7. Fold the handlepost down by releasing the handlepost joint.
  8. Secure the handlepost with the rubber strap.

6.2 How to roll and park the Vektron

You can vertically park and roll the folded Vektron.

Rolling

To roll your folded Vektron, extend the Telescopic Seatpost, lift the front of the bike, and push it forward.

Parking

  • To vertically park the Vektron, carefully lift the folded bike backward until it rests on the rear rack ends.
  • To park the folded Vektron lengthwise, ensure that the bike rests on the Underframe Support.

In both cases, please ensure that the bike rests on a flat surface. Keep in mind that the Vektron can only be vertically parked when completely folded. 

6.3 How to unfold the Vektron

  1. Release the handlepost strap and unfold the handlepost, making sure the handlepost joint locks in place.
  2. Turn the handlebars to disengage the magnet.
  3. Pull the bike’s front end up to unfold the frame, then secure the frame joint by closing the lever.
  4. Engage the kickstand and adjust the Andros Stem and seatpost to your desired position.
  5. If you’ve removed the pedal, remember to reattach it before securing the plastic ring.

See the Vektron fold in action—check out our step-by-step instructions on YouTube to fold and unfold with confidence.

7. Max Gross Vehicle Weight

The Vektron ebike has a Max Gross Vehicle Weight (MGVW) of 125 kg, or 276 lb. This means that the combined weight of the e-bike, accessories, rider, and any cargo must be less than 125 kg. If you’d like to know which Tern accessories are compatible with the Vektron, read our Vektron Accessory Guide.

8. Daily riding checklist

Before every ride, give your bike a quick check—look over your tire pressure, brakes, battery, chain, cables, and quick-release points. For the full rundown, watch our daily riding checklist video, and don’t miss our basic maintenance tips to keep your bike in top shape.

9. Ready for the ride?

That’s it! You now have all the basics to get started with your new Tern Vektron folding electric bike. If anything’s unclear, you can revisit this article, the Owner Briefing, check the Vektron QuickStart Guide, or swing by your nearest Tern dealer. You can also browse our Frequently Asked Questions about the Vektron.

And don’t forget—we love hearing from you! Join our Tern Riders' Club Facebook group and share your adventures. See you there, and happy riding!