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Swingarm mounted Hub Motor

9042 Views 28 Replies 11 Participants Last post by  Functional Artist, 
RIPPERTON
I would like all of you engineers and designers to comment on this design of bike. Tell me what you think the ridability would be like considering the hub motor is mounted on the swingarm.

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Duncan
remy_martian said:
The wheel torque is reacted to by the frame through the swingarm. Physics 101.

The motor is invisible to the frame if it's centered on the swingarm pivot. All forces are purely between the motor and wheel and the reaction to the motor torque is by the swingarm lever acting on the axle pin. Not the swingarm pivot. The torque of the motor is translated to the wheel. You coupd argue that the motor is pulling on the chain which lifts the frame at the swingarm pivot, but that is defined as wheel torque.

So, he was correct.
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No he was wrong the torque is reacted to the FRAME through the pin and pivot
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R
...by the WHEEL
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Duncan
remy_martian said:
...by the WHEEL
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To the frame - AND to the wheel - as Newton said opposite and equal
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R
Yes...but not the motor. Everything he posted is correct.
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R
Duncan said:
To the frame - AND to the wheel - as Newton said opposite and equal
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Almost equal.

Newton didn't burn rubber obviously 😂
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Duncan
remy_martian said:
Almost equal.

Newton didn't burn rubber obviously 😂
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Nope all wrong - just think about it - with the motor at the pivot point and the wheel locked I energise the motor - what happens? the motor torque causes the swinging arm to MOVE

If the wheel is not locked you get the same effect -
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R
You cheated, old man.

You introduced a new reaction element - brakes, which spoil the torque translation.

Fun as this is...I need to get some sleep or I'll be crankier than usual in my postings tomorrow 🤓
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kennybobby
How is that motor mounted to the swingarm? i see fasteners on each end of the motor shaft, but is there a stationary shaft thru the middle of the rotor, or what holds the motor...?
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F
I mounted an electric motor on the fulcrum of the swing arm of an old Kawasaki 440, back in 2017
...& now, have put over 1,000 miles on it (so far) with-out any issues (no jacking or squatting or anything)

It's very "nimble" to maneuver & ride (kind of like a big dirt bike)
...& doing this, left so, so, so much more room for the battery pack ;)

Here is a video that (kinda) shows the motor, it's mounting location & batt pack :cool:
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