Stromer does not repair Stromer parts or components. Dealers who send in defective components (battery, motor, controller, etc.) will receive new parts in exchange.
Bearing damage
Motor failures in newer Stromer models are rather rare. The old 36V motors (ST1 V1 / V1.1) with integrated electronics still had many problems and failures due to overheating and, in some cases, water ingress.
As mileage increases, engine mounts can become a problem, but they are not noticeable in breakdown statistics.
A non-representative survey in the forum speedpedelecreview.com It resulted in the following:
Survey participants: 52
• Reports of defective motor mounts: 18 (equivalent to 35 % units among participants)
• Average kilometers driven: 16,267
• 50 % participants covered a distance of 10,000–20,000 km
• Average km to failure: 12,824 km
Shortest Distance to Failure: 1,000 km
• Longest distance to failure: 27,000 km
The author concludes that he had actually expected more participants. Only 35 of the participants reported bearing damage. Since approximately 1,000–1,500 Stromers have been sold annually in the Netherlands since 2017, the negative feedback would have to be significantly higher if there were a genuine problem. Since there is also little to be found on social media regarding engine bearing issues, the problem cannot be significant—so he concludes.
Bearing dimensions
TDCM motors most commonly use the following bearings: deep groove ball bearings: D = 68 mm, d = 45 mm, B = 12 mm, with ZZ (or 2Z) metal shield.
With Aliexpress Are there suitable replacements (in stainless steel) for approx. 20 CHF per pair. Brand-name bearings, e.g. from SKF, are better: 6909-2RS (1 | 2 | 3 | Designation scheme SKF | Components and materials)
It is recommended to verify the bearing type based on the existing bearings, as different manufacturers' motors (ASI, Ultra, TDCM) and their respective bearings were used throughout the model's development.
Tip: When disassembling the engine, you shouldn't skimp on replacement bearings – sealed bearings extend the service life.
Bearing repair only
Riesewjik, Netherlands
Price tag: approx. €500–€600 (excluding shipping)
All motor repairs (incl. Hall sensors, thermistor, motor cable, etc.)
Bikes & Care, Netherlands
Price tag: unknown
Andrzej Romanow
On the German portal classifieds.com there were advertisements from a supplier Andrzej under the geolocation 02828 Saxony - Görlitz, which advertised repairs of electric motors.
Advertisement: (As of January 2024)
Andrzej wrote to me on request:
My name is Andrzej and I live in Wroclaw, Poland. I've been involved with Stromer bikes for seven years and have a lot of experience with them, but mainly with the V1, ST1 and ST2 models...
In my workshop I have assembled the appropriate equipment and tools (see pictures below) to open, repair and refit Stromer rear wheels...
I have attached a price sketch (see above) to my classified ad offer. In addition, the details will be agreed in direct contact with the customer.Over the last two years I have perfected the gluing of magnets to the steel ring in Stromer engines. First I built special tools for gluing magnets onto the old ST1 model and in the last few months I have also built my own tool set for gluing magnets onto the ST2 and newer models.
Contact us
E-Mail: attributebiker@onet.eu
WhatsApp: +48 50 809 87 18
Price tag: See advertisement above
Personal experience
My ST3 motor needed new bearings after 31,000 km. Additionally, the rim (Alex Rim) had cracks at the spoke holes. I sent the motor, a new rim (DT Swiss H612), spokes, and nipples to Andrzej. The repair process and discovered issues (including a broken retaining bracket on the motor connector and two notches on the axle) were documented via WhatsApp, and I was asked for instructions on how to proceed. The repair with lacing cost €250 (including transport and customs from Poland).
Shipping from Switzerland by Swiss Post cost CHF 111. I recommend that Swiss customers use a German address or Packstation for the repair.
Feedbacks in the Stromerforum.ch
Repair: Hall and temperature sensor(s), stator magnets, motor cable, etc. Replacement of bearings.
Repair of defective spokes, rims. Re-spoking to alternative rims (DT Swiss 612/683 / RYDE Andra 29D)
Costs: Depending on expenditure: (as of July 2025)
- Bearing replacement from € 290. This service includes two splash-proof bearings, which are better than the dust-proof standard bearings. The engine is cleaned and checked internally.
- RYDE Andrea 29D rims (5 mm narrower) are very robust and reasonably priced.
146 €, fully assembled. - DT Swiss U 683 (if available), cargo rim.
161 €, fully assembled. - DT Swiss H 612, the standard rim for the Stromer ST5.
179 €, fully assembled.
Contact us
Bart Berger, e-bike bike repair
Smidsestraat 93
9200 Grembergen (Belgium)
www: https://www.ebikewheelrepair.be/
DIY repairs
Those with manual skills can also tackle the work themselves. As always, there are many ways to get to Rome.
The user Lexveen has disassembled a defective ST1x motor and describes its construction with text and images in speedpedelecreview.comForum.
A blog post from tech-coulombus also describes the removal and installation, including pictures.
Tool: e.g. PAULIMOT Universal puller, 3-armed, 300 mm span
There are also a few pictures of a disassembled TDCM engine here at pedelecforum.de
Motor cable / plug / socket
Cable for: ST5 2021 ABS | ST5 2018 | ST3 2022 Pinion | ST3 2018 | ST2 2020 Belt | ST1 2021 LCI | ST1 2019 – with Higo connector: Type HG-F.M-L1019A Buy at: 1 | 2 | 3)
Cable for: ST2/ST2S
Hall sensors / temperature sensor
See PROBLEMS > Motor - 'Hall or temperature sensor defective?
Repainting
See PROBLEMS > Motor > 'Paint peeling off'