First Build - Pics And Questions

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Nei2172

New Member
Hey everyone I'm getting started on my first electric build, I've built a gas bike before but I'm wanting to put together an electric to ride on the bike paths... you get tired of the loud 2-cycle engine noise after awhile. I've decided to put together my own system using a large 36v scooter motor. I will also be using a controller pulled from an electric scooter. As you can see in my pics below I plan on mounting the motor on the downtube in front of the crank. I plan on putting together a front freewheel so the pedals won't spin when using the motor. I would love to have a dual front freewheel, but after doing some research here and and on google I don't think anyone sells components to easily make a dual front freewheel. From what I've read the only place to get semi-inexpensive parts to build a front freewheel is here: http://www.sickbikeparts.com/catalog/index.php?cPath=21&osCsid=eb2665b9bd0b9a0d057357d5f359fbec is that the only place? Or is there somewhere better/easier/cheaper? OK so on to my questions... First of all I don't understand how to build a front freewheel with the parts listed on that page. Which specific parts do I need? I have never taken apart bicycle gears/cranks/shafts so I'm a complete noob in this department. If I buy the right parts from that page are they all going to bolt together and install without me having to weld or do anything hard? Is it that simple or will it require more work than I'm thinking? My next question is will I be able to find a sprocket that fits on this motor that will fit a regular bicycle chain? The motor shaft is shaped to fit a sprocket with a dual D-bore like this:
SPR-2511C2.jpg


So I'm thinking if I can put together the front freewheel crank setup, find a sprocket for the motor that I can use with a bicycle chain, and figure out a good way to mount the motor I'll be set. The motor is just taped on right now so you can get an idea of what I'm thinking. Do you think this setup will work? Am I missing anything? I realize that when I'm pedaling only I will have added drag because I'm turning the motor, I am fine with this. That is unless I had a dual front freewheel, I don't think that is available anywhere though.

Ok so give me some tips! I think the hardest part for me is goung to be setting up the freewheeling front crank so the pedals don't spin when the motor is running. Any insight here would be MUCH appreciated. Here are the pics:
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Hi Nei2172. Yes everything you are asking about can be done. The dual front freewheel is complicated and requires welding up an adapter but it is a dream to ride - no drag and 7-10 speeds (depending on your rear cassette) for pedaling and motor. Also an infinite choice of how much you want to assist the motor by pedaling. You can also get a freewheel sprocket to go on the motor so you only have to turn the motor chain rather than the whole motor when you pedal with the motor switched off. SBP sells everything you need to convert the front crank and chainring (sprocket) to freewheel. Jim ([email protected]) is very helpful with technical info. You can buy the parts a la carte. You'll need a crank set, freewheel, bottom bracket cartridge or bearing kit and spindle, 2 chainrings plus their hardware kit. The freewheel threads onto the right crank and the chainrings bolt onto the freewheel so when the motor spins the chainrings, the chain back to the cassette turns but the pedals can remain still.

It doesn't look like your motor has a built-in reduction unit. You want the crank speed to be under 100 rpm so if it spins at at 3000 rpm you have to find a way to get about 30:1 reduction. That's too much for a single reduction as your 11 tooth motor sprocket would require a 330 tooth chainring! So you'll need either a planetary or a jackshaft to help with that. Allelectronics.com sells a planetary but I don't know if it will fit your shaft or if it's strong enough. Another option would be to mount the motor above the rear forks and drive the rear wheel using a sprocket mounted on the left side like the 2-smokers do or else drive it from the right side using the granny gear of the cassette. Its only one speed that way but might be simpler for you. In any case you'll need to mount the motor sturdy and in good alignment. Keep us posted and don't be afraid to ask questions. You can PM me if you want more detailed info - jd
 
I wish I could help you but I have never built a freewheel of any kind. I'm sure someone here can help though. The freewheel crank from a tandem bike might work though I have no idea where you would get such a thing.

I am going with a ebike motor and rear wheel already set up for the drive. I'll just have to make sure to get the motor lined up well. The drive goes on the opposite side of the wheel from the pedal sprocket.
 
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Jcdburg, thanks for the info! I never thought about gear reduction. Would the setup still work without gear reduction? I wouldn't have much take off power but it would still pull me once I was moving right? Or does it burn the motor up because it is wanting to spin at 3000 RPM but I'm only letting it spin at 200 RPM? It will be much easier if I can get away without gear reduction!! :)
 
Just found a pic of a bicycle on cyclone's website that looks exactly how I want mine set up.
3pcs-1000B.jpg


I wish there was cyclone style kit available that didn't cost so much... I also wish I could buy a pre made mount for my motor like that.
 
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I believe Cyclone does have a built-in planetary. You can try anything you want, regardless of what others (including me) suggest. Please look at any of Deacon's posts. It's amazing what he gets to work. Remember bicycles (bearings, gears, brakes, spokes, tires) are not made to go any faster than they can be pedaled. Check your state's laws. Accidents involving motored bikes make it easy for the lawmakers to come down hard on a minority like us - jd
 
jdcburg said:
I believe Cyclone does have a built-in planetary. You can try anything you want, regardless of what others (including me) suggest. Please look at any of Deacon's posts. It's amazing what he gets to work. Remember bicycles (bearings, gears, brakes, spokes, tires) are not made to go any faster than they can be pedaled. Check your state's laws. Accidents involving motored bikes make it easy for the lawmakers to come down hard on a minority like us - jd
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Yes, most states (and countries) don't really allow DIY bicycles to propel you faster than 20mph(32kph) on their roads...

I'm curious as to why people DONT use hub motors? They're more efficient then external chain drive units. I'm guessing the only reason people use others is because hub motors are usually twice the price. However, you will get better bang for the buck in terms of distance and efficiency with the hub motors.

I'm thinking though, after all is said and done with the other types of motors they end up costin the same amount after adding is chains, throttles, controllers, etc etc.


Just my .02

any thoughts on that?

Or I'm I just unaware of other types of motors(kits) and their advantages?
 
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I keep babbling about that , but that is , really , matter of personal choice , habit and money . People tend to buy brushed motors , just because they are familiar with them(widely available) and , some , resent the fact that most hubs comes from China.
 
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