Motor for front sprocket??

[DT98]

I know this has been discussed but I haven't found any posts...so I will ask, what's the up and down side of using a motor for the front sprocket on a bicycle? It seems it would let you use the gearing on the rear wheel...I must be missing something because I have never seen one actually. Thanks, DT98

 

[gogo]

I think I saw a forum here dedicated to non-hubmotor drives, but I'm not sure.

 

[TylerDurden]

You can see a few versions by searching the terms: mid-drive, cyclone, through the gears, non-hub.

We have a dedicated non-hub section:
http://endless-sphere.com/forums/viewforum.php?f=28

 

[Hillhater]

what's the up and down side of using a motor for the front sprocket on a bicycle? It seems it would let you use the gearing on the rear wheel...

Simply put, to replace the front chainwheel directly with a motor, you would need a motor that runs at the same speed as you pedal ..50 -100 rpm. It would take a very special motor to work efficiently (or at all ) at that speed.

 

[DT98]

Geez...it never dawned on me that this would be a non-hub drive...dooh... Thanks, DT98

 

[DrkAngel]

EZip gear motor seems perfect for this project.
I plan on placing the motor in the triangle and dropping a chain around one of the inner front sprocket rings.

This should bring motor speed and pedal speed into alignment.
Alternate would be to run at 36v.
Either solution should equalize motor and pedal speed capability.

Motor is 450w at 24v - 675w at 36v. (900w at 48v, requires "restraint" to prevent motor damage!)

 

[DrkAngel]

EZip gear motor seems perfect for this project.
I plan on placing the motor in the triangle and dropping a chain around one of the inner front sprocket rings.

This would cause reduced pedal speed, from the 9T motor gear.
Solution? Placing a 14T freewheel on the motor gear.
This should bring motor speed and pedal speed into alignment.
Alternate would be to run at 36v.
Either solution should equalize motor and pedal speed capability.

Motor is 450w at 24v - 675w at 36v. (900w at 48v, requires "restraint" to prevent motor damage!)

OOPS! Got it backwards ... :?

Gear ratio info:
OEM bike provide motor 9T - axle 20T = 16mph
Through, equal size front sprockets (9T: 34T = 10mph, 11T = 30mph)
& F sprocket gear addition of 25-50% = 12.5-37.5 mph or 15 - 45mph (Too high for motor!)
Higher voltage recommended, with motor attached to large sprocket, and wheel chained to smaller sprocket!
36v could provide a solid 8 to 24 mph or, 10 - 30mph range - w/3x torque at low end!
If your sprocket supports custom size rings, you can dial in the "perfect" ratio.

Possible, 7spd "motor" bike enhancements:
Removal of pedals;
Removal, or reduction, of cranks;
Adding foot pegs;
Lowered "full" seat;
11-34T 7spd gear cartridge

 

[spinningmagnets]

The pedal-axle is properly called a Bottom-Bracket,...so also search Bottom Bracket drive, and BB-drive.

There are a lot of them here...both factory and custom...

 

[DrkAngel]

EZip 450w 24v geared motor - $108.89

 

[blueb0ttle2]

You can go even lower on those if you use tncscooters.

 

[DrkAngel]

Better prices on the EZip geared motors!



450W GEARED Motor - 24 Volts (Style: MY1018Z) Price: $65.00

250W GEARED Motor - 24 Volts (Style: MY1018Z) Price: $55.00