Higher speeds, higher risk

With tuning active, motor assistance can continue up to approx. 45 km/h. Always wear a helmet and suitable protective clothing.

Only for e-mountain bikes

whose manufacturer declares EN 15194 and EN ISO 4210-2 in the bike's EU declaration of conformity. City and trekking e-bikes are not suitable.

More wear, shorter intervals

Brakes, drivetrain, frame, steering and saddle are loaded more heavily. Shorten inspection intervals and check the bike before every ride.

Battery range drops

because the motor works at full power for longer.

Warranty and insurance

Claims against the bike manufacturer may lapse or be limited. Accident and liability insurance may not cover rides with a tuned bike – check your cover.

Safety systems unchanged

Brakes and all other safety functions of the e-bike stay as they are.

Lock the bike

whenever you park it, so nobody else uses it on public roads.

The principle

A magnet passes the speed sensor once per wheel turn. From the time between these pulses, the motor calculates your speed and stops assisting at 25 km/h.

MountainTuning sits exactly in this signal path. With tuning active, it passes the real speed through up to approx. 22 km/h. Above that, it hands the motor a speed signal that stays below 25 km/h – so the motor keeps assisting up to the maximum speed you have set. Motor, battery and all safety functions of the bike are not changed.

Where the signal is adapted

• SmartChip V2: a small module between speed sensor cable and motor, inside the motor compartment.
• SmartSensor: replaces the original speed sensor of the Bosch Smart System.
• SpecB: replaces the original speed sensor at the rear brake disc of Specialized bikes.
• Splug: a cable harness leads out to a magnetic holder. The tuning logic is in the removable dongle – no dongle, no tuning.

SmartChip V2, SmartSensor and Splug for Bosch

• ✓Bosch Smart System (BES3) or Gen5 – recognisable by the square charging plug. A round plug means Gen2/Gen3/Gen4: not compatible.
• ✓Classic spoke magnet with speed sensor on the rear frame. Not for bikes with a rim or valve magnet.
• ✓No ABS.
• ✓Bosch firmware up to and including 21.12.0.
• ✓Works with any Bosch display.

SpecB for Specialized / Brose

• ✓Drive system: Brose Drive / Specialized 1.2, Brose Drive S / Specialized 1.3 or Brose Drive S Mag / Specialized 2.1.
• ✓Your model is on the SpecB compatibility list.
• ✓Not for systems that detect a divided speed signal.

Splug for other systems

• ✓Choose the version for your motor: Shimano EP8/EP800, Yamaha PW-X3/PW-S2 and Giant SyncDrive Pro2, or Panasonic/Flyer 2-pin.
• ✓Each product page lists the exact requirements.

5.1 SmartChip V2 – Bosch Smart System

1. 1Put the bike in a safe, stable position and remove the battery.
2. 2Loosen the screw(s) of the motor cover and take the cover off. On some bikes the crank has to come off first.
3. 3Pull the speed sensor plug out of its socket in the motor compartment.
4. 4Plug the speed sensor cable into socket A of the SmartChip.
5. 5Plug the SmartChip's other cable end B into the socket in the motor compartment.
6. 6Check that both plugs sit fully and the right way round – mind the guides on the connectors.
7. 7Place the SmartChip in a suitable spot, often directly in the connection area of the motor. Route the cables like the original sensor cable, away from all moving parts.
8. 8Refit the motor cover. Make sure no cable rubs or gets pinched, then tighten the screws.

5.2 SmartSensor – Bosch Smart System

1. 1Put the bike in a safe, stable position and remove the battery.
2. 2Take the motor cover off – on some bikes a crank arm has to come off first. Unplug the speed sensor cable in the motor compartment.
3. 3Unscrew the original sensor on the rear frame, usually next to the thru-axle, and pull its cable out of the frame. Tip: pull a draw wire through with it.
4. 4Route the 1,200 mm SmartSensor cable through the frame along the same path and mount the SmartSensor in the original holder, facing the magnet at the same distance as the original.
5. 5Plug the SmartSensor into the sensor socket in the motor compartment. Mind the guides on the connector.
6. 6Refit cover and crank without pinching any cable.
7. 7Keep the original sensor safe – you need it to return the bike to its original condition.

5.3 SpecB – Specialized / Brose

1. 1Remove the battery or unplug the battery connector.
2. 2Protect the motor housing with a little tape, loosen the screws of the motor cover and lift the left side of the cover downwards.
3. 3Pull the speed sensor plug out of the connection terminal in the motor compartment.
4. 4Find the original speed sensor on the rear frame next to the brake disc, usually near the thru-axle. Unscrew its holder and take the sensor out.
5. 5Pull the old sensor cable out of the frame. Tip: tie a thin draw wire to the cable end and pull it through with the cable – then pull the new cable back in along the same route.
6. 6Route the SpecB cable through the frame, place the SpecB in the original holder and screw the holder back on. The sensor must face the magnet on the brake disc at the same distance as the original.
7. 7Plug the SpecB connector into the terminal by hand. Avoid pliers – if you need them, grip gently. Mind the inner shape of the plug.
8. 8Arrange the cables so the cover closes without obstruction, put the cover back and tighten the screws.
9. 9Keep the original sensor safe – you need it to return the bike to its original condition.

5.4 Splug

1. 1Open the motor cover as described for your drive system (5.1 for Bosch).
2. 2Plug the Splug cable harness in between the speed sensor cable and the motor socket: sensor cable into the harness, harness into the motor socket.
3. 3Route the thin cable out of the motor compartment, away from moving parts.
4. 4Fix the magnetic holder with cable ties: on the frame, or near the handlebar/display with the 100 cm handlebar version.
5. 5Refit the motor cover without pinching any cable.
6. 6Attach the dongle to the holder – the magnets pull it into place.

1. 1Put the bike in a safe, stable position (e.g. on a workstand).
2. 2Insert the battery and switch the system on. With Splug: dongle attached.
3. 3Turn the rear wheel by hand without pedalling.
4. 4The display must now show a speed.

8.1 Before you begin

• ✓The function test has passed: the display shows a speed when you turn the wheel.
• ✓Bike on a workstand, rear wheel free to turn. On Specialized bikes the magnet sits on the brake disc instead of a spoke – everything works the same way.
• ✓With Splug: dongle attached.
• ✓Specialized / Brose with a transponder immobiliser: deactivate it for the time of programming.
• ✓Know the sensor's active zone. The magnet counts as „in front of the sensor“ only in a short arc of its path, roughly the quarter of the turn where it passes the sensor. Find this spot once by turning the wheel slowly.

8.2 Open the menu

1. 1Switch the system off and wait a moment.
2. 2Turn the rear wheel until the magnet sits in front of the sensor.
3. 3Switch the system on. What counts is the moment the system starts (e.g. an LED lights up), not when the display is fully ready.
4. 4Keep the magnet in front of the sensor for about 4 seconds.
5. 5Move the magnet away for about 1 second (turn the wheel a little).
6. 6Bring the magnet back in front of the sensor:
   ≥ 4 s → operating mode menu ≥ 8 s → maximum speed menu
7. 7Move the magnet away. The product is now in programming mode and the display shows a speed value.

No value? Switch off and start again at step 1. The timing does not have to be exact to the second – count calmly.

8.3 Choose the mode

Each full turn of the rear wheel (the magnet passes the sensor once) moves one step on:

The order matters, not the exact number – values depend on your wheel size. After each turn, make sure the magnet does not stop in front of the sensor.

8.4 Set the maximum speed (v-max)

Open the menu with the long hold (at least 8 seconds). The display now shows the speed up to which the motor will assist. Each wheel turn moves one step on; the value shown is the new limit. Assistance continues up to approximately this speed.

8.5 Save – or discard

• Save: hold the magnet in front of the sensor for at least 4 seconds. The display shows 0 km/h and stays there. Switch the system off and on again – the new setting is active.
• Discard: switch the system off without saving. The last saved mode and v-max stay unchanged.

After programming, repeat the function test before you ride.

Display

With tuning active, the speed shown is real only up to approx. 22 km/h (depends on wheel size). Above that it stays below 25 km/h. For your real speed use GPS, e.g. a smartphone in a handlebar mount.

Odometer and ride data

Total distance and all values calculated from speed no longer match the real ride while tuning is active.

Real speed again

In mode 2 „Tuning always off“ and with the Splug dongle removed, the display shows the real speed.

Bosch firmware

Compatible up to and including 21.12.0. Do not install newer Bosch updates until MountainTuning has confirmed them. Never update with the Splug dongle attached. Dealers often install updates during a service – tell them before every inspection.

Before every ride

Check condition and function of:

• ✓Brakes
• ✓Frame
• ✓Steering
• ✓Drivetrain
• ✓Saddle and seatpost

Also carry out every check the bike manufacturer requires. Ride only if the bike is in perfect condition – and only on private, secured land or permitted race tracks.

Disposal

Never put electronic parts in household waste. Use the collection points for electrical waste in your area, or return the product to your dealer.

WEEE registration

WEEE-Reg.-Nr. DE 26243129

Support

Questions about installation or programming? Our team helps.

All MountainTuning products are available exclusively at EBikeTuningShop.com.