Electric Retrofit Tandem

Calfee eBike Retrofit Service

Calfee Design has developed the best solution for cyclists interested in electric assist. We will elegantly retrofit a state-of-the-art Pedal Assist to almost any bike, including tandems.


Our system is both expandable and customizable. You can run it with as few or as many batteries as you actually need. Unlike other eBikes, you can legally bring these modular batteries on an airplane. In addition, swapping back and forth to your original setup is quick and easy, just remove the top tube bag and replace the powered wheel with your original. The internal wiring stays installed and out of the way.

Motor, Controller and Batteries!

The Calfee eBike Retrofit Service uses 3rd generation front or rear hub motors. Power ranges can be selected from a minimal 250 watts system up to 600 watts for a more robust assist level. Need more climbing power or would you prefer more top speed? We set the system to your preferences even if you want both!

    • A retrofit for any bike, including carbon fiber
    • 250 Watts to 600 Watts variable power
    • Battery system allows for additional capacity
    • PAS via drivetrain sensors
    • Customizable and scalable system


Retrofit Type  Typical Range  Build Turnaround Time
Single Bike  40 miles  4 to 6 weeks
Tandem  50 miles  6 to 8 weeks
Custom Build  To Specification  Quote

Every aspect of the our retrofit is tuned to work together and then expertly fitted to your bicycle. Components are selected to be compatible with your existing drivetrain and type of brakes. We then consider the rider’s experience and type of riding conditions expected. We then make a recommendation of the optimal motor, controller and number of batteries needed. We then run the proposed scenario through an online simulator which you can also manipulate if you’d like.

Typical motor simulation using a Bafang MG310.
Typical motor simulation using a Bafang MG310.

Every detail is managed and made to work elegantly together. On Calfee carbon frames, wiring is internally routed and motor wires guided by expert unobtrusive frame modifications. We will make other suggestions for safety and performance such as braking enhancements.

Ready to be energized?

Power is supplied by the modular LiGo battery packs from Grin Technology. A modular battery means your system is lightweight and expandable for more assist range as needed. The number of LiGo cells selected for the system will determine the maximum power and range of the retrofit. Why pay for – and carry more than you really need?

Each LiGo pack is 2.7Ah (610g) and can be combined with additional packs to create a larger capacity battery system. In addition the LiGo battery packs are travel-ready, conforming to FAA passenger aircraft flight regulations.

Prices range from $1,895 to $3,500 on the typical retrofit. You send us your garage decoration and we’ll send back a high performance hill flattener.

2019 Calfee Manta eBike retrofit.
2019 Calfee Manta eBike retrofit.

Get the most out of your older bike with an expert Calfee eBike Retrofit.



Calfee Design 1-800-965-2171