Minimum Primary Transmisison Factors (eBike Applications)

Revised primary transmission factors for eBike applications:

The SPEEDHUB is an incredibly robust bicycle transmission. Although not initially designed with the eBike market in mind, the SPEEDHUB has proven itself more than capable for reliable use in the heavy-duty ebike sector. As the eBike sector grows and evermore powerful motors are developed, the market moves farther from that which is traditionally reviewed as a bicycle, and therefore farther from that for which the SPEEDHUB was originally developed. Rohloff have been reviewing the market for some time and although we are convinced that the SPEEDHUB remains the most durable biocycle transmission available, the time has come to set some limitations for this new area of application.

The minimum primary transmission factor requirements for most eBike applications will remain the same, but changeds have been made to the heavy-duty eCargo/eTandem sector. The minimum primary transmission factors for all the various eBike applications have been illustrated in the easy to follow table format below.

 

Vehicle type Primary Transmission Factor max. Input Torque at
SPEEDHUB Sprocket*
EU Approved
eBike Motor**
Non EU Approved
eBike Motor***
max.
System Weight
max.
Wheel Load
Solo Bicycle
Rider weight = ≤100kg
1.9 130 Nm ✔️ ✔️ 250 kg 150 kg
Tandem
Rider weight = >100kg
2.5 130 Nm ✔️ 250 kg 150 kg
Cargo / Recumbent
(single-track vehicles)
2.5 130 Nm ✔️ 250 kg 150 kg
Cargo / Recumbent
(multi-track vehicles)
SPEEDHUB located in wheel
2.5 130 Nm ✔️ 250 kg 150 kg
Cargo / Recumbent
(multi-track vehicles)
SPEEDHUB located in wheel
3.0 130 Nm ✔️ >250 kg 150 kg
Cargo / Recumbent
(multi-track vehicles)
SPEEDHUB located in frame
2.5 130 Nm ✔️ 250 kg ---
Cargo / Recumbent
(multi-track vehicles)
SPEEDHUB located in frame
3.0 130 Nm ✔️ >250 kg ---

✔️  Approved and Authorized for SPEEDHUB use    
❌ Non approved / Not authorized for SPEEDHUB use    
* 130Nm input = force created by rider, plus motor, divided by Primary Transmission Factor (PTF)

e.g.:    

  • Rider creates 150Nm. Motor creates 100Nm. PTF of 2.5 = 150+100 = 250/2.5 = 100 (100Nm = OK).
  • Rider creates 250Nm. Motor creates 100Nm. PTF of 2.5 = 250+100 = 350/2.5 = 140 (140Nm = NOT OK).

** Max. 250W Nominal Power / Max. 800W Peak Power    
*** Max. > 250W Nominal Power / Max. > 800W Peak Power