Adapter installation guide
Shimano EP8, E6100 and E8000 motors: reliability and issues encountered
Shimano Steps motors are among the most widespread systems on urban electric bikes, trekking and electric mountain bikes. Unlike some competitors, Shimano generally favours natural pedalling, careful integration and well-developed electronics. However, each generation has experienced specific defects that have marked its reputation.
Shimano EP8 (DU-EP800)
Presentation
Launched in 2020, the Shimano EP8 succeeds the very popular E8000. It develops:
- 85 Nm of torque,
- 250 W nominal,
- a weight of approximately 2.6 kg,
- advanced customisation via the Shimano E-Tube app.
It notably equips high-end e-MTBs from brands such as:
- Orbea
- Santa Cruz Bicycles
- Pivot Cycles
- Merida
- Cannondale.
Main issues
Rattling noise on descent ("EP8 Rattle")
This is probably the most well-known defect of the EP8 motor.
When the cyclist stops pedalling on a descent or rough terrain, a metallic rattling can occur inside the motor. This noise comes from the internal freewheel mechanism. It generally does not cause a breakdown but has been widely criticised by users.
Many testimonies on Reddit describe this noise as normal on the early EP8 generations.
Noises and creaks under load
Some users report:
- clunks on ascent,
- creaks during hard accelerations,
- noises that appear after several thousand kilometres.
In many cases, the source is not the motor itself but:
- the cranks,
- the bearings,
- the motor/frame interfaces,
- loose transmission elements.
Motor axle issue
A series of EP8 motors experienced cracking of the internal bottom bracket axle, mainly when non-approved Shimano cranks were used. Shimano has recorded several dozen cases.
Reliability assessment
Despite these criticisms, the EP8 is considered to be a generally reliable motor. The issues are more related to noise and some peripheral components than to massive failures of the motor itself.
Shimano Steps E8000
Presentation
Launched in 2016, the E8000 was the first Shimano motor specifically designed for sporty e-MTB.
Features:
- 70 Nm of torque,
- weight of approximately 2.9 kg,
- assistance up to 25 km/h.
Main issues
Error W013 (torque sensor)
This is the most well-known failure of the E8000.
The W013 message corresponds to a problem with the torque sensor initialization. In some cases, it is enough to properly restart the bike without pedalling. In other cases, the motor needs to be replaced.
Error E010
This more general error causes :
- total loss of assistance,
- system shutdown,
- inability to restart normally.
The causes may be :
- communication failure,
- connectors,
- battery,
- internal electronics of the motor.
Cracking noises
After several thousand kilometres, some users report :
- cracking at low speed,
- noises under assistance,
- feeling of mechanical play.
However, Shimano and many workshops find that these noises often come from :
- the bearings,
- the motor housing,
- the bottom bracket,
- or a lack of maintenance.
Reliability assessment
The E8000 is now considered a robust and durable motor. Many examples exceed 10,000 km without major intervention. Its faults mainly concern certain electronic errors and the aging of sensors.
Shimano Steps E6100
Presentation
The E6100 appeared in 2018 for urban and trekking bikes.
Features:
- 60 Nm of torque,
- smooth and quiet operation,
- strong trekking and city orientation.
It can be found on many models :
- trekking,
- electric hybrid bikes,
- high-end urban bikes.
Main issues
Clacking noises during assistance recovery
Several users have reported a dry noise :
- during the recovery after a descent,
- at the moment when the assistance reactivates,
- when crossing the 25 km/h limit.
This phenomenon seems to have been accentuated by certain software updates.
Errors W013 and E010
Like the E8000, the E6100 may present :
- error W013,
- error E010,
- total loss of assistance.
These faults remain relatively rare but often require a Shimano diagnosis.
Assistance cut-offs
Some users report :
- stopping of assistance after a few kilometres,
- failure appearing more during climbs or under heavy load,
- temporary restart after system shutdown.
Reliability assessment
The E6100 is probably the most reliable of the three motors. It is less powerful than the EP8 but also less mechanically stressed. Serious failures remain relatively rare and mainly concern the electronics or certain sensors.
Conclusion
In terms of pure reliability :
- Shimano E6100 : the most reliable and least problematic.
- Shimano E8000 : very robust but sensitive to certain electronic errors (W013, E010) with age.
- Shimano EP8 : very high-performance motor but criticised for its famous internal rattling and some teething problems on certain series.
For a workshop or a second-hand buyer, the most frequently encountered problems remain :
- the errors W013 and E010 on E8000/E6100,
- the freewheel noise ("rattle") on EP8,
- the creaks related to the motor/crank interfaces rather than the motor itself.