Many bike manufacturers now equip some of their ebikes featuring the Bosch Smart System without a separate display. Combinations of the Bosch System Controller with a Bosch Mini Remote or alternatively with a Bosch LED Remote are then often installed. If you would like to add a small display to this constellation, the Bosch Purion 400 has recently become an excellent option. This short tutorial shows you step by step how to retrofit the display to your ebike system.
Case 1: Fitting the Bosch Purion 400 to an ebike with Bosch Mini Remote
Case 2: Fitting the Bosch Purion 400 to an ebike with Bosch LED Remote
Case 1: Fitting the Bosch Purion 400 to an ebike with Bosch Mini Remote
Initial situation:
- Ebike with Bosch Smart System
- Control unit: Bosch Mini Remote + Bosch System Controller
- Display cable routed from frame through stem to handlebars
Parts required:
- Bosch Purion 400 with handlebar clamp 31.8 mm or 35 mm
- Mounting screw
- Dummy plug
- Additional Y-display cable, length 800 mm or 950 mm
- Torx screwdriver
1. Preparations for mounting
When starting the work, remove the battery from your ebike so that the system is not energised. To reach the connections on the motor, it is sufficient to remove the motor cover on most Bosch motors. remove the motor cover. If your bike is powered by a Bosch Performance Line SX, you will even have to partially remove the motor from the bracket.
2. Remove the System Controller
Use a Torx screwdriver to loosen the fastening screw on the System Controller and pull the control unit upwards out of the top tube. Pull off the inserted display cable and let it hang out of the frame.
3. Route the new display cable in the frame
Attach the single end of the Y-display cable to the old display cable and route both together through the frame. A little adhesive tape is sufficient to connect the two cables. You can also pull heat-shrink tubing over both cables, heat it and proceed in a professional manner. In any case, you can use the old display cable to pull the new Y-cable all the way through from the top tube to the motor.
Tip: You can use the Y-display cable to connect both the Purion 400 and the System Controller to the motor with a single cable. It is available in two different lengths in our shop: 800 millimetres and 950 millimetres. In case of doubt, the longer cable is probably the safer choice.
4. Rout the Y-ends of the display cable
At the moment, both ends are still sticking out of the opening for the system controller in the top tube. Plug the shorter end of the display cable directly into the control unit. This will prevent it from accidentally getting into the frame during the following steps. Before we can connect the longer end to the Purion 400 on our ebike, the trickiest part of the retrofit awaits us. As there is no other option, we loosen the bolts of the semi-integrated stem, remove it and pull all the spacers off the steerer tube. We then pull the fork out of the head tube. At this point, we need the support of a second person to hold the fork in the meantime. Perhaps you can find a suitable solution so that you can put the fork down and continue working alone.
By removing the fork, the head tube is now completely free. This means that the longer Y-end can be fed through without any problems. The fork is then pushed back into the head tube. Then thread the display cable through the spacers together with all the other cables. At the end of this procedure, we put the stem back on.
5. Initial function test
You can now test the new setup for the first time. To do this, plug the corresponding three ends of the display cable into the motor, System Controller and Purion 400, reinsert the battery and activate the e-drive on the System Controller. If all components switch on as usual and the new display is also recognised, you can start with the final assembly steps. If not, check again whether all plugs are correctly engaged or whether a cable is jammed at some point.
6. Complete retrofitting the Purion 400
First remove the battery to minimise the risk of injury. Then reattach the System Controller to the top tube using the small Torx screw.
On the Purion 400, place the dummy plug on the unused connection so that no moisture, dirt or humidity can penetrate the slot. Then clamp the Purion 400 bracket around the handlebars and click the display into place. Once you have found the desired position on the handlebars, lock everything together with the corresponding screw. If you had to loosen the motor from the motor mount at the start of the retrofit, screw it on again now. If you didn’t have to do this, simply attach the motor cover at this point. Finally, reinsert the battery – et voila – you have retrofitted the Bosch Purion 400 to your ebike.
Alternative: Installation using two separate display cables
For completeness, it should be mentioned that you could theoretically work with two display cables of different lengths instead of the Y-display cable. In this case, the longer one would connect the Purion 400 and the motor. The shorter cable would lead from the display to the System Controller. However, this would mean having to run two cables instead of just one in the area of the stem and head tube – where the space is probably already heavily utilised by existing cables. We wanted to avoid this additional effort on our example ebike with the semi-integrated stem. And with the Y-display cable, there is actually a good solution for this.
Case 2: Fitting the Bosch Purion 400 to an ebike with Bosch LED Remote
Initial situation:
- Ebike with Bosch Smart System
- Control unit: Bosch LED Remote
Parts required:
- Bosch Purion 400 with handlebar clamp 31.8 mm or 35 mm
- Mounting screw
- Additional display cable, length approx. 250 mm
- Torx screwdriver
1. Install Bosch Purion 400 on the handlebars
If an LED Remote is the only control unit on your ebike, you can retrofit the Bosch Purion 400 in just a few minutes. To be on the safe side, first switch off the e-drive and remove the battery from the ebike. You can then start fitting the new display to the handlebars straight away. To do this, place the clamp with the appropriate diameter around the handlebars. Then click the Purion 400 into the bracket on the clamp so that it snaps into place with a small clack. To ensure that the display now remains in the desired position on the handlebar, use the enclosed locking screw to secure the clamp.
2. Establish the connection to the Bosch LED Remote
In the next step, pull the display cable out of the LED Remote and plug it into one of the two ports on the Purion 400. Then the additional display cable comes into play. Plug one end of it into the remaining free port on the Purion 400. Route the other end to the LED Remote and plug it in there. Now you can reinsert the battery and switch on your ebike as usual. Once it has recognised the new display, the Purion 400 can be operated via the LED Remote.
