MikeSSS
1 kW
Previous ebike used a direct drive, no Hall sensor, front hub and a 48V, 13.5 shark battery in the rear rack. First host bike was a rigid 3 x 6 speed sort of mtb, second host was a Jamis Hudson 1 x 7 that is sort of like a Townie. Those bikes worked just great but no suspension was too rough at times.
"New" build uses an old Mongoose FS mtb, 3 x 7, from back when Mongoose was a bike shop bike. Rear hub motor is a MAC 12T purchased from EM3ev, with matching controller, half twist throttle and a Cycle Analyst V3. Battery is a 52V, 20Ah, 14s, 8p, it weighs 12.2 lb, about half the weight of the gel cell battery I started with 6 years ago.
The Grin rear torque arm I got was made to attach to the seat stay, but that pivots. I made torque arms for both sides, fitted more snugly than the Grin TA. The cassette side uses two 3/16" arms welded together to give 3/8" thickness and a forward arm 6" long that transfers torque to the bottom of the chain stay. Two U bolts are used to hold the forward arm to the chain stay, they resist the torques attempt to pull the axle downward out of the dropout. So the TA resists torque and provides axle retention, in addition to the axle nut. The other side TA is similar but is open on top to admit the motors wires. This TA uses a 7/16" bolt to provide axle pinch. 7/16" because those nuts are big enough to be easy to weld to the TA. Like the other side, this TA resists torque and provides axle retention to assist the axle nut.
On the road and bike paths, the FS does indeed have a much superior ride to the rigid host bikes. The MAC 12T has more low speed power than the DD front hub had, top speed is about the same at 25 mph. Both were fine for my normal 12.5 mph average speed. There is less noise from the MAC than the sensorless DD at times when the DD made some cogging resonance. Otherwise both have been pretty quiet. When there was no cogging resonance, the DD was very quiet.
I tried CA throttle settings of Pass Thru and Amps, for me Pass Thru gives better low speed control and also works better with the Cruise Control function. The throttle bottom point was adjusted a bit for better low speed stuff and less initial dead band.
Using CC is really nice. Cruise is particularly useful on climbs, the rider just worries about steering, balance, shifting, cadence, and human power, Cruise handles the throttle and e-power. After 77 miles using the CA, I'm sold on it.
On a 40 mile ride, average amps were 6.9, average watts were 112, avg mph was 11.4 and avg miles per Amp hour were 5.74. It's been 39 degK in the sun, in the afternoon, highest observed hub temperature has been 62 degK.
Over 77 miles the MAC has averaged 5.65 mi/Ah. The old Aotema direct drive averaged 3.46 mi/Ah over 612 miles at an average of 12.5 mph, but that was based on recharge data and may be low. It is likely the sensored gear motor is more efficient than a sensorless direct drive motor.
So, I'm happy with an old FS bike using a rear hub motor, used for gentle riding.
"New" build uses an old Mongoose FS mtb, 3 x 7, from back when Mongoose was a bike shop bike. Rear hub motor is a MAC 12T purchased from EM3ev, with matching controller, half twist throttle and a Cycle Analyst V3. Battery is a 52V, 20Ah, 14s, 8p, it weighs 12.2 lb, about half the weight of the gel cell battery I started with 6 years ago.
The Grin rear torque arm I got was made to attach to the seat stay, but that pivots. I made torque arms for both sides, fitted more snugly than the Grin TA. The cassette side uses two 3/16" arms welded together to give 3/8" thickness and a forward arm 6" long that transfers torque to the bottom of the chain stay. Two U bolts are used to hold the forward arm to the chain stay, they resist the torques attempt to pull the axle downward out of the dropout. So the TA resists torque and provides axle retention, in addition to the axle nut. The other side TA is similar but is open on top to admit the motors wires. This TA uses a 7/16" bolt to provide axle pinch. 7/16" because those nuts are big enough to be easy to weld to the TA. Like the other side, this TA resists torque and provides axle retention to assist the axle nut.
On the road and bike paths, the FS does indeed have a much superior ride to the rigid host bikes. The MAC 12T has more low speed power than the DD front hub had, top speed is about the same at 25 mph. Both were fine for my normal 12.5 mph average speed. There is less noise from the MAC than the sensorless DD at times when the DD made some cogging resonance. Otherwise both have been pretty quiet. When there was no cogging resonance, the DD was very quiet.
I tried CA throttle settings of Pass Thru and Amps, for me Pass Thru gives better low speed control and also works better with the Cruise Control function. The throttle bottom point was adjusted a bit for better low speed stuff and less initial dead band.
Using CC is really nice. Cruise is particularly useful on climbs, the rider just worries about steering, balance, shifting, cadence, and human power, Cruise handles the throttle and e-power. After 77 miles using the CA, I'm sold on it.
On a 40 mile ride, average amps were 6.9, average watts were 112, avg mph was 11.4 and avg miles per Amp hour were 5.74. It's been 39 degK in the sun, in the afternoon, highest observed hub temperature has been 62 degK.
Over 77 miles the MAC has averaged 5.65 mi/Ah. The old Aotema direct drive averaged 3.46 mi/Ah over 612 miles at an average of 12.5 mph, but that was based on recharge data and may be low. It is likely the sensored gear motor is more efficient than a sensorless direct drive motor.
So, I'm happy with an old FS bike using a rear hub motor, used for gentle riding.
