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Old 02-22-2013, 02:10 PM   #7 (permalink)
razor02097
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Join Date: Jan 2013
Location: ohio
Posts: 306

Tetanus - '95 Geo Tracker 4WD Base
90 day: 29.43 mpg (US)

300 - '82 Suzuki GS300 L
Last 3: 60.78 mpg (US)

Jeep - '98 Jeep XJ Cherokee Limited
90 day: 12.82 mpg (US)
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Quote:
Originally Posted by govman6159 View Post
I 100% guarantee you the bike in the link you posted will not get you anywhere near 50 miles AER. My guess is 6-8 miles in the real world. I don't care what the advertisement says. Its a 15AH battery pack powering up to a 1400 watt motor.
It's also a 52v system. 52v*15ah is 750 watthours. Your 24V battery is 30ah so 24v*30ah is 720 watthours.

Quote:
Originally Posted by govman6159 View Post
Additionally I see many drawbacks to this bike:
1) Unsprung weight of the hub motor - the motor is to the back of the bike and is unsprung weight on the wheel (causing it to be harder to pedal)
2) The battery pack is high mounted and to the back (this causes an unstable bike that will fall over easily and take bumps hard in the back. The front wheel will come off the ground easy too).
3) The motor is not geared (this limits hill climbing and assist, it also puts a severe strain on the battery and the motor (even when climbing small hills))

Here is a better set up (its called a mid mount motor). This allows you to continue to be able to shift the bike and use assist through all gears. It also reduces the strain on the battery and the motor when climbing hills. This type of setup eliminates all the drawbacks listed above.
Unsprung weight on a bicycle is actually good. The more weight put on the frame the less rider/cargo weight the bike can carry. It won't make it any more difficult to pedal than the weight of a motor sitting on the frame.
  • Hub motors are less complicated. There are no gears, chains or extra freewheeling hubs to have to mess with.
  • There are hub motors that are available with regenerative braking.
  • Hub motors are easier to mount, they just replace a wheel.
  • They are much quieter and they are (at least to me) more aesthetically Pleasing.
  • When choosing a hub motor one should make sure to size it correctly. You can get a hub motor that is geared...they have massive torque and you can get away with a smaller motor. However it is typically louder and not as fast.
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