In this video, we are thrilled to show you how to finally and reliably unlock the speed limit on a Bosch Smart System eBike equipped with a rim magnet (specifically shown on a Focus Jam²). Because the factory speed sensor is hidden in the valve stem, standard tuning chips do not work. The SpeedFun Furious Evo Easy kit solves this by bypassing the rim magnet entirely and installing a secondary spoke magnet system alongside a specialized electromagnet. Let’s get into the installation!
Step-by-Step Installation Guide
Phase 1: Preparation and Motor Removal
- Prep the Bike: Flip your eBike upside down. You will need to drop the motor to install this specific chip.
- Remove the Battery: Pull the tab at the top of the motor housing and pull the main battery out of the frame.
- Remove the Motor Covers (Bash Guard): Remove the small screw on the drive side, and the multiple Torx screws on the non-drive side and rear of the plastic motor covers. You can often remove the covers in two pieces without needing to take the crank arms off.
- Drop the Motor: Locate and loosen the three main motor mounting bolts on both sides. In most cases, you do not need to remove the chainring; you can reach the bolts right through it.
Phase 2: Installing the Electromagnet
The kit includes a thin plate with an electromagnet. This sends a modified pulse to the motor to trick the factory sensor.
- Position the Plate: Tilt the motor up to access the rear casing. Place the electromagnet plate against the casing so the white line on the plate lines up with the mold line on the motor, and the small hook clips into place.
- Secure the Plate: Because eBikes experience heavy vibrations, we highly recommend adding a small dab of hot glue to the top and bottom of the electromagnet to hold it firmly in place against the motor casing.
- Re-seat the Motor: Push the motor back down into the frame and loosely thread the mounting bolts in. Ensure the motor fits comfortably with the new plate wedged behind it, then tighten the bolts.
Phase 3: Installing the Spoke Speed Sensor
- Mount the Sensor Housing: Take the plastic sensor housing block provided in the kit, open it, place the new speed sensor wire inside, and snap it shut.
- Attach to Chainstay: Using cable ties, mount this sensor block to the inside of your rear chainstay. Ensure it is placed far away from the electromagnet, but clear of the disc brake rotor.
- Install the Spoke Magnet: Attach the provided magnet to a spoke so it passes directly in front of the new sensor block. The gap between the magnet and the sensor should be between 5mm and 15mm.
- Secure the Wire: Run cable ties along the chainstay to secure the sensor wire tightly. You do not want this wire catching in your tire tread!
- Remove the Factory Rim Magnet: Take the valve cap off your tire, loosen the retainer, and remove the original factory rim magnet entirely.
Phase 4: Connecting the Wiring
- Sensor Connection: Connect the gold plug on the tuning chip to the new speed sensor wire you just ran along the chainstay.
- Electromagnet Connection: Connect the small plug from the tuning chip to the electromagnet wire (line up the tiny arrows on the plugs).
- Motor Connection: Locate the black cable plugged into the motor right next to the main battery plug. Pull this black cable out. Plug it into the large round port on the tuning chip (line up the white line on the cable with the symbol on the chip port).
- Final Chip Connection: Take the last remaining wire coming from the tuning chip and plug it into the empty port on the motor where you just removed the black cable. The square embossed section of the plug should face towards your seat post.
Phase 5: Troubleshooting and Testing
Before putting all the covers back on, test the system!
- Reinstall your battery and turn the bike on. Look at the tuning chip; you should see a solid red light.
- Slowly spin the rear wheel. Every time the spoke magnet passes the new sensor, the red light on the chip should blink off and back on. This confirms the sensor is reading correctly.
- Look at your display while spinning the wheel; it should register a speed reading.
- If everything works, neatly tuck all the wires into the frame and reinstall your motor covers.
Note on the Speedometer: With this specific chip installed on a Smart System with a rim magnet, your actual speed will exceed 25 km/h, but the display will stop at roughly 20 km/h. To track your true speed, we recommend using a GPS device or your phone.
Watch the full video below for a complete visual walkthrough and a nighttime test ride!