Best 250W electric middle motor?

[5e bike]

Hi guys,

I'm relatively new at this, and I need some of your help to find appropriate motor. I want to put motor in middle of bike, between bike pedals and have transmission to rear wheel via shaft drive system. I'll use Shimano Nexus as rear hub gear. For optimal range, is better to have 36V motor or 48V, considering different current through motor? Output shaft should be adaptable to be attached to the shaft drive front gearbox. So, all your suggestions are welcome, any help would be appreciated

 

[Tom L]

Have a read of this: http://endless-sphere.com/forums/viewtopic.php?f=28&t=42785
Do a search for "cyclone" on this forum.
Also, http://www.af-tech.com.au/ could be an option.

I'm looking at the same sort of set up but as yet have not tried any of them so can not make a recommendation, sorry.

As for your voltage question, it depends. You need to have the motor running at its efficent rpm (not too low) which can take a higher voltage (depending on the motor's winding) but for simplicity's sake, range is mainly dependent on the battery's "Watt-hours" (voltage x capacity in Ah).

 

[dnmun]

it is getting closer to biking season down there at davis. first day of spring tomorrow!

he was asking about shaft drives and from what i could understand he wants the motor to drive the shaft that goes from the 'crank' to the rear hub which is a long shaft inside a tube/ cover.

this is gonna be difficult because if you connect to the shaft, then the motor will drive the pedals too, they will not be able to freewheel if i understand the design of the nexus. if the nexus has the freewheel at the crank then this may work if you can put that shaft into some pillow block bearings/cut the shaft and then insert a pulley in the middle with the drive from the motor mounted adjacent the drive tube, colinear. you would have to weld the pulley on one side of the cut and use the set screw of the pulley to catch a groove you cut in the shaft to lock them together in use. that will allow you to assemble it, and replace the belt later.

 

[Warren]

How about one of these?

http://www.evworld.com/press/protanium_shaftdrive_profile480x320.jpg

 

[dnmun]

does that use the nexus shaft drive? you can see where the motor would have to be mounted behind the pedal arc alongside the shaft tube. i would expect you could even weld the mounts for the motor to the frame there and secure the shaft tube and pillow blocks for the bearings there.

 

[Miles]

5e,

You're planning to use the Sussex drive?
http://www.nochainbike.com/eng/display/home.php?mode=shaft

http://www.sussex.com.tw/shaft-drive.html

 

[Tom L]

it is getting closer to biking season down there at davis. first day of spring tomorrow!

Indeed. It has just gone 12/12 daylight/night hours. Still far too much ice and snow about (meters deep all over station) for anything less than Honda quad biking at the moment though.

he was asking about shaft drives and from what i could understand he wants the motor to drive the shaft that goes from the 'crank' to the rear hub which is a long shaft inside a tube/ cover.

Interesting. First I've seen of that drive type. Sorry for the mis-direction.

 

[Suspect]

Why do you want a shaft drive? Would you consider a belt drive? Seems like you could get some of the same features but it would be easier to implement.
I have a mid-drive that uses a 24 V Kollmorgen motor. My battery is 25.6 V, 12.5 Ah, lithium chemistry that I've probably got 4000 miles on in the last 4 or 5 years.
I take the bike on lots of 30-35 mile road rides and 10 to 15 mile trail rides and I've never once run it dead. Of course I pedal though. I basically go as fast as me and the motor can go.
Partly I went this way because the motor was available but I like the low voltage for other reasons (water resistance, reliability, use for accessories).
I'd recommend a setup like mine. I love it.
I believe you also said you wanted an IGH and that's an upgrade I would like to make. I've been running an 8 speed derailer and it demands more maintenance than any other component. I've changed the derailer once, the cassette two or three times, and the chain two or three times. The dirt, dust, and mud are especially hard on these bits.

 

[Warren]

"does that use the nexus shaft drive? "

The motor is the drive shaft!

http://evworld.com/news.cfm?newsid=28478

http://www.protanium.com/resources/Shaft_motor_specs.pdf

 

[Miles]

How about one of these?

http://www.evworld.com/press/protanium_shaftdrive_profile480x320.jpg

Well... all they've done, so far, is create a prototype. Who knows when/if it will be available.....?

 

[5e bike]

Thank you guys for posts

if the nexus has the freewheel at the crank

It has a freewheel, I checked

that will allow you to assemble it, and replace the belt later.

So, basically I'll have belt drive to drive a shaft drive? This system you described could work, but I was thinking to do something more elegant and maybe avoid belt I would rather use gears to drive the shaft from motor, don't know if that would be possible using Sussex shaft drive.

You're planning to use the Sussex drive?

I was really thinking about using their drive, but I still need to find appropriate way to drive it with the motor and by the pedals (pedals should freewheel if there's no cycling, and co-drive the shaft when I'm cycling)

Why do you want a shaft drive?

Because it's easier for maintenance and has a good torque transmission. I haven't found any 250W Kollmorgen motors. I need exactly that power (EU restrictions).

I still need a good 250W motor recommendation, as small as possible, so it' could fit near the shaft drive on bicycle

 

[dnmun]

gears seem elegant, but you gotta think of lubrication now, and then enclosing it to keep out dirt, and then there is the noise of gear lash.

it would be neat to see if the merido type drive would turn the crank and the shaft would go to the nexus 7 in back. georgeinvt had a similar drive, but that way you would have the gears contained inside the housing, helical to pinion on the crank too.

 

[Paul_G]

Hi guys,

I'm relatively new at this, and I need some of your help to find appropriate motor. I want to put motor in middle of bike, between bike pedals and have transmission to rear wheel via shaft drive system. I'll use Shimano Nexus as rear hub gear. For optimal range, is better to have 36V motor or 48V, considering different current through motor? Output shaft should be adaptable to be attached to the shaft drive front gearbox. So, all your suggestions are welcome, any help would be appreciated

This bike is a 250W mid motor and seems priced right. If you around NYC get a test ride.

http://www.evelo.com/electric-bicycles/aries/