MikeSSS
1 kW
My wife is small, 5', 115lb, she does not ride much because climbing is a problem for her. So, we need a bike that meets her needs but also lets her go riding with me. Thanks to ES and Marty S we now have that magic bike. Apologies for not knowing how to post a pic or two of the bike.
The bike: it is a 24" wheel Townie 7d, the grip shifter has been changed to Rapid Fire, the fixed chainring crank was replaced with one having a much smaller chain ring and 152.5mm crank arms. Electra makes a rack for this bike, got it and mounted a plastic cutting board on it and a 15" Harbor Freight bag on the cutting board, to carry the battery, water bottle and snacks. Townies have an aluminum frame, a steel fork and are designed with pedals forward so the rider can more easily reach the ground when stopped. This is a rigid bike, no suspension. The 7 speed freewheel has a 34 tooth big cog.
We used a Bafang G311 front hub motor from Grin along with a 20 amp Grin controller. G311 is a front hub from the G01 series, it is 11:1 gear reduction with helical cut gears and no drag when not powered. This hub fit perfectly in the front dropouts, it has a round 10mm axle and uses torque tabs in the inside of the dropout on both sides. This is a silent hub, at least I can't hear it.
Battery used has been a 48v, 13ah, 13s, 4p, Panasonic GA cell shark from Luna. The Grin 20A controller uses Anderson Power Poles, the battery has an XT 90 anti spark connector, so I just bought a Power Pole to XT 90 adapter from Luna.
Grin built the wheel using an Alex 24" rim, this rim is wider than the Townie rim, but the Brakes had just enough extra cable to fit the new rim.
Installing the kit presented no problems, though the wires were shorter than I expected, the controller is now mounted on the bottle cage, reaching the off and on button is easy. There is some conflict between the thumb throttle and Rapid Fire levers, we might change to a twist throttle and besides when we rent Honda Metros they use a twist throttle.
Performance was sort of shocking, the G311 is much smaller and lighter than my Aotema direct drive front hub. From a start the 311 accelerates better than my DD and it also climbs better too. Battery use appears to be substantially less than my DD, but I'm not really sure because my wife is lighter and she averages about 9 mph, but I ride solo at more like 12 mph average.
Next step is to find a lighter weight battery for her. The Luna shark weighs about 8 pounds and it is mounted on top of the rear rack. We need lighter so the bike feels less top heavy.
So, in 20 miles of riding my wife has loved the bike. She uses power only part of the time on level ground but really enjoys coasting up the climbs. I've been riding pedal power with her and am getting a good workout on those climbs, she drops me like a rock.
I'd really like to thank Drunkskunk for telling me about the G311 motor and other things, thanks to Marty S at HUB MRKT here in San Antonio for much advice and thanks to all who post here on ES. There is so much to learn and it takes a while to digest so much new information that it can be confusing.
PS, it you are ever in San Antonio when Frankenbike is happening, often third Saturday, be sure and stop by. These are the bike culture people, the forever bike lovers. They are the bike kids who got older but never outgrew bikes.
The bike: it is a 24" wheel Townie 7d, the grip shifter has been changed to Rapid Fire, the fixed chainring crank was replaced with one having a much smaller chain ring and 152.5mm crank arms. Electra makes a rack for this bike, got it and mounted a plastic cutting board on it and a 15" Harbor Freight bag on the cutting board, to carry the battery, water bottle and snacks. Townies have an aluminum frame, a steel fork and are designed with pedals forward so the rider can more easily reach the ground when stopped. This is a rigid bike, no suspension. The 7 speed freewheel has a 34 tooth big cog.
We used a Bafang G311 front hub motor from Grin along with a 20 amp Grin controller. G311 is a front hub from the G01 series, it is 11:1 gear reduction with helical cut gears and no drag when not powered. This hub fit perfectly in the front dropouts, it has a round 10mm axle and uses torque tabs in the inside of the dropout on both sides. This is a silent hub, at least I can't hear it.
Battery used has been a 48v, 13ah, 13s, 4p, Panasonic GA cell shark from Luna. The Grin 20A controller uses Anderson Power Poles, the battery has an XT 90 anti spark connector, so I just bought a Power Pole to XT 90 adapter from Luna.
Grin built the wheel using an Alex 24" rim, this rim is wider than the Townie rim, but the Brakes had just enough extra cable to fit the new rim.
Installing the kit presented no problems, though the wires were shorter than I expected, the controller is now mounted on the bottle cage, reaching the off and on button is easy. There is some conflict between the thumb throttle and Rapid Fire levers, we might change to a twist throttle and besides when we rent Honda Metros they use a twist throttle.
Performance was sort of shocking, the G311 is much smaller and lighter than my Aotema direct drive front hub. From a start the 311 accelerates better than my DD and it also climbs better too. Battery use appears to be substantially less than my DD, but I'm not really sure because my wife is lighter and she averages about 9 mph, but I ride solo at more like 12 mph average.
Next step is to find a lighter weight battery for her. The Luna shark weighs about 8 pounds and it is mounted on top of the rear rack. We need lighter so the bike feels less top heavy.
So, in 20 miles of riding my wife has loved the bike. She uses power only part of the time on level ground but really enjoys coasting up the climbs. I've been riding pedal power with her and am getting a good workout on those climbs, she drops me like a rock.
I'd really like to thank Drunkskunk for telling me about the G311 motor and other things, thanks to Marty S at HUB MRKT here in San Antonio for much advice and thanks to all who post here on ES. There is so much to learn and it takes a while to digest so much new information that it can be confusing.
PS, it you are ever in San Antonio when Frankenbike is happening, often third Saturday, be sure and stop by. These are the bike culture people, the forever bike lovers. They are the bike kids who got older but never outgrew bikes.
