Hi,
I've seen several 50cc conversion topics on ES that seemed very attractive to me . So I decided to give it a try myself.
I bought for a few bucks a 50cc moped with a dead engine and removed all the guts.
Found on ES 2 PEHV battery module to make a 72V 30Ah pack
And purchased a QS138 3kw middrive with votol EM150 which seems to be a popular combo for this kind of conversion.
Here is where I am ATM and I wanted to open a topic to share my thinking about motor mounting.
Everyone fixes the motor to the frame at a location close to the ICE motor it replaces. But I want to try another solution by fixing it to the swingarm , kind of similar to the swingarm QS sells
except I would place the motor in front of the pivot and not behind as QS
I would lasercut 2 steel plates and weld them to the swing arm as on this 3D sketch. I think it can make a stiff attachment.
Here is the layout of the Rieju. I would only have to modify the lower frame by welding some square tubbing to receive the battery
Advantages and drawbacks of this solution, at least as I see it :
advantage :
- easy motor install outside of the bike
- Position of the motor sprocket for a correct chainline is necessarily OK, in line with the wheel axle and swingarm pivo. No need to place the sprocket at the exact same location as original motor
- no need of chain tensioner or lower guide as chain line dosen't change during suspension movement. It would be easy to cover the chain or replace it with a belt
- motor torque and chain tension affects less the suspension behaviour compared to a motor fixed to the frame (in my understanding, maybe I'm wrong ...)
drawbacks :
- it adds unsprung weight but close to the pivot so much less rotating inertia compared to the wheel itself
- it requires clearence inside the frame for the motor movement, so less room for battery
- motor power wires movement may cause their failure on long (or short) term ( but if it's OK on QS swingarm ...)
So what to you guys think of this option ?
I've seen several 50cc conversion topics on ES that seemed very attractive to me . So I decided to give it a try myself.
I bought for a few bucks a 50cc moped with a dead engine and removed all the guts.
Found on ES 2 PEHV battery module to make a 72V 30Ah pack
And purchased a QS138 3kw middrive with votol EM150 which seems to be a popular combo for this kind of conversion.
Here is where I am ATM and I wanted to open a topic to share my thinking about motor mounting.
Everyone fixes the motor to the frame at a location close to the ICE motor it replaces. But I want to try another solution by fixing it to the swingarm , kind of similar to the swingarm QS sells
except I would place the motor in front of the pivot and not behind as QS
I would lasercut 2 steel plates and weld them to the swing arm as on this 3D sketch. I think it can make a stiff attachment.
Here is the layout of the Rieju. I would only have to modify the lower frame by welding some square tubbing to receive the battery
Advantages and drawbacks of this solution, at least as I see it :
advantage :
- easy motor install outside of the bike
- Position of the motor sprocket for a correct chainline is necessarily OK, in line with the wheel axle and swingarm pivo. No need to place the sprocket at the exact same location as original motor
- no need of chain tensioner or lower guide as chain line dosen't change during suspension movement. It would be easy to cover the chain or replace it with a belt
- motor torque and chain tension affects less the suspension behaviour compared to a motor fixed to the frame (in my understanding, maybe I'm wrong ...)
drawbacks :
- it adds unsprung weight but close to the pivot so much less rotating inertia compared to the wheel itself
- it requires clearence inside the frame for the motor movement, so less room for battery
- motor power wires movement may cause their failure on long (or short) term ( but if it's OK on QS swingarm ...)
So what to you guys think of this option ?