belt drive.

[scott jewell]

I have done some low budget chain drives with several Unite motors using 20" wheels on a 24" bike and have two motors front and rear on a 20" BMX.

I also have two hub motors on bikes but am looking at a belt drive instead of a jack-shaft for a 29" wheel on my new project. A 24 volt 500 watt 2,500 rpm motor on a rear rack .

I priced the sheave kit but am looking specifically for the motor attachment part. It is a dual D bore shaft.
With disk brakes front and rear the rear rack will be a challenge but sure they make one. I am looking that up now.

I have a simple bag which straps to the handlebars from another build. It held a controller and is big enough for two LiPo packs. I want a simple low budget build. At 36 volts rpm is 3750 I believe so am seeking 14 to 1 reduction for approx. 23 mph gearing.

The sheath comes in one size so the motor pulley needs to be the right size. If there is no such part then a steel pulley could be used and a 11 tooth #415 sprocket could be used and holes drilled into the pulley wheel and attached together by bolts.

My first build was a Unite 1,000 watt replacement for a stock 24V 450 watt Currie ezip. I bolted it to the rear rack which held the SLA box and did a battery mount on the frame towards the front for weight distribution so I could haul a lot of cargo. Thanks and please let me know of any parts or kits I can use.

 

[Sonoboy]

LOVE my belt drive. The only downside is I will NOT consider a chain drive bike anymore...so my choices are limited. Maybe... if it's a chain drive to a Rohloff. But that's it.

 

[scott jewell]

Was your motor part of a kit or did you have to find an attachment for it.

I want to build my first belt drive but like a puzzle I need to know I can acquire all the pieces before attempting to put it together.

Also simplicity is more valuable to me than complex. I mid drive which utilizes all the gears thru the motor or a jack-shaft for gear reduction it way too complex.

A friction or belt drive is more simple and a belt drive would work better for hills and greater speed capabilities.

I have been told that a rear sheave which is approx. $35 will work on a 29" wheel. Also since it is a rear drive and the motor I intend to use is kind of heavy the controller and battery pack can go in a bag which straps to the front handlebars for even weight distribution.

The issues I will need to solve are proper gear reduction therefore to achieve this the roller attachment for the motor will need to be a specific size. 14 to 1 reduction is desirable for 23 mph at 1 horsepower (750 watts)
I will need to use a tape measure and measure the rear sheave and then divide by 14 and that will be the size I will need for the motor pulley. Also I was hoping to be able to use a common serpentine belt or something similar I can pick up at an auto parts store.

I am not totally familiar with belt drives but know that if a chain breaks or pops off at high speed it can be a major safety hazard but a belt is less dangerous. Also a common belt from any auto parts store should be cheaper as well as faster to replace than ordering an expensive belt online.

Therefore my biggest question is what type of roller will I need for the motor. It is a common 48 volt Unite 1,000 watt motor with a dual D bore motor shaft. It may be possible to drill four small holes in a steel pulley wheel and bolt it to an 11 tooth #415 motor sprocket if there are no wheels which will fit the Dual D motor shaft. Here is a picture of the motor and specifications.

(Link Removed - No Longer Exists)

I have a choice of using this motor or a 48 volt 1,000 watt motor however I prefer this motor over the 48 volt motor as I was thinking about using the 48 volt motor for a different build. Thanks and please let me know if anyone has any helpful information or suggestions.

LC out.