I am underway in building two more matching fat tire commuter ebikes for myself. In preparation for this build, I built two prototypes which was a good thing because I found many things that needed to be improved upon:
(1) I needed more copper in my motor because the 40mm rear hub motor would heat to 108 degrees C after 6 miles,
(2) my 160mm rotor mechanical disc brakes did not provide enough stopping power for the 340 lb (bike + rider + cargo) load,
(3) the 46T chain ring (in conjunction with an 11T small cog in freewheel) was useless after 31 mph with 30.5" diameter tires,
(4) the rear hub motor axle of the Crystalyte 4060 motor was 2mm too short for the 170mm dropout frame,
(5) the 150mm dropouts in the rear hub motor did not match the 170mm dropouts in the frame (I needed to use 1/2" washers & nuts as spacers),
(6) the adjustable stem was a major safety hazard,
(7) the 50A BMS was not able to deliver the current that I needed, and
(8) I needed to create a thick Kevlar tire liner to avoid flats in these thin walled tires.
Here is a YouTube video of one of the prototypes.
My new bikes have Cromotors with custom wide axles (190mm dropout (shoulder), 268mm length) seen here:
built into a 36h Surly Rolling Darryl using a 2 cross pattern and 13ga spokes as such:
The frame is a 190mm dropout Design Logic Da Phat cargo frame built around a Vee Snowshoe 2XL:
I am using Tektro Dorado hydraulic brakes with 203mm rotors, a CA V3, half twist throttle, multifunction switch (power on/off switch, regen, 3 speeds), a Lyen Mark 2 24 FET 4110 controller at 72V and 20Ah LiMn battery with a 100A BMS and 90A circuit breaker (on each 36V battery in series).
The tires are the 2XLs as mentioned above on a Surly Clownshoe (100mm aluminum, 32h, 14ga spokes) in a Surly Ice Cream Truck fork in front and 36h Rolling Darryl in the rear.
Drivetrain is a Surly Mr. Whirly crankset (Moonlander spindle) with a 58/110mm Surly spider, 175mm Surly crank arms and a single Vuelta USA 110BCD 58T chainring going back to a Sunrace 5-speed 14-28T freewheel.
This part about the torque arms has been updated:
One of the most fun aspects of the project is making the torque arms. I had a machine shop make some 1/4" 303 SS plates with a D-hole that matches the huge Cromotor axle. I will powder coat these torque arms and drill two holes that bolt the TA to the frame. The torque arm will hold the axle (and wheel!) securely in place as well as prevent axle rotation.
(1) I needed more copper in my motor because the 40mm rear hub motor would heat to 108 degrees C after 6 miles,
(2) my 160mm rotor mechanical disc brakes did not provide enough stopping power for the 340 lb (bike + rider + cargo) load,
(3) the 46T chain ring (in conjunction with an 11T small cog in freewheel) was useless after 31 mph with 30.5" diameter tires,
(4) the rear hub motor axle of the Crystalyte 4060 motor was 2mm too short for the 170mm dropout frame,
(5) the 150mm dropouts in the rear hub motor did not match the 170mm dropouts in the frame (I needed to use 1/2" washers & nuts as spacers),
(6) the adjustable stem was a major safety hazard,
(7) the 50A BMS was not able to deliver the current that I needed, and
(8) I needed to create a thick Kevlar tire liner to avoid flats in these thin walled tires.
Here is a YouTube video of one of the prototypes.
My new bikes have Cromotors with custom wide axles (190mm dropout (shoulder), 268mm length) seen here:
built into a 36h Surly Rolling Darryl using a 2 cross pattern and 13ga spokes as such:
The frame is a 190mm dropout Design Logic Da Phat cargo frame built around a Vee Snowshoe 2XL:
I am using Tektro Dorado hydraulic brakes with 203mm rotors, a CA V3, half twist throttle, multifunction switch (power on/off switch, regen, 3 speeds), a Lyen Mark 2 24 FET 4110 controller at 72V and 20Ah LiMn battery with a 100A BMS and 90A circuit breaker (on each 36V battery in series).
The tires are the 2XLs as mentioned above on a Surly Clownshoe (100mm aluminum, 32h, 14ga spokes) in a Surly Ice Cream Truck fork in front and 36h Rolling Darryl in the rear.
Drivetrain is a Surly Mr. Whirly crankset (Moonlander spindle) with a 58/110mm Surly spider, 175mm Surly crank arms and a single Vuelta USA 110BCD 58T chainring going back to a Sunrace 5-speed 14-28T freewheel.
This part about the torque arms has been updated:
One of the most fun aspects of the project is making the torque arms. I had a machine shop make some 1/4" 303 SS plates with a D-hole that matches the huge Cromotor axle. I will powder coat these torque arms and drill two holes that bolt the TA to the frame. The torque arm will hold the axle (and wheel!) securely in place as well as prevent axle rotation.
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