Go cart parts + Junk = First Build

[rybitski]

I recently decided that I was going to build an E-bike. After alot of searches on the internet for information I stumbled across ES linked from another forum (you guys aren't easy to find). Wonderful things going on here by the way, excellent source of information and knowledge. You guys have helped me so much already and this is just my first post.

The plan for my build are as follows:
350 Watt Currie motor 11 tooth driving 24 tooth (#25 chain) connected to jackshaft with 10 tooth driving a freewheel mounted 60 tooth (#35 chain).
The reason for using #35 chain is that I already had the sprockets and 10 ft of chain left over from my youthful go cart building days. I wanted to use #35 chain throughout, but could not find a 10mm #35 sprocket (Currie output shaft is 10mm). I don't have the money for any 123 packs so SLA is the route I have chosen for power (college students don't have money). I have a connection with someone who manufactures batteries so they are hooking me up with some genesis np18-12's. I will wire 2 in series for a 24 V system. All this crap will be mounted onto my POS walmart mountain bike. The full suspension is making the design a but harder, but I have a game plan.

Work so far:
60 tooth freewheel





motor mount




Frame


This should give you an idea of where I want to mount it (up off the tire of course)

Layout



Here is a .jpeg of the assembly. A better quality .pdf is attached if anyone is interested.

Because the motor mount ended up being made out of aluminum I had to alter the frame a bit.

This is the progress as of today after spending the morning in the scene shop welding and cutting. (I am a technical theater major so the scene shop is pretty much where I live)
I will try to keep this updated with pictures and progress reports as stuff comes together. Thanks for reading! Questions/comments/suggestions welcome.

 

[amberwolf]

Looks good enough; I'd definitely find a way to move the batteries down and forward, though. It'll handle a lot better.

 

[recumpence]

Very good steel work!

I whole-heartedly agree on the weight, though. That much above the rear wheel will make for bad handling. That aside, your system looks pretty decent. Those currie motors are relatively reliable and easy to work with.

Matt

 

[zap]

Nice welding on the teeth of that sprocket!
Good luck with the build and I vote also to get the weight of those genesis lower... 26 lbs. + the motor that high will be unwieldy.
Hang em off the side but watch for heel strike.

 

[kartopla]

Great fab skills and welding. I use the same motor on my friction drive trike. One note. Chain is dang noisy. I use a gates belt for a 3 to 1 primary. Then use chain. Much quieter. Chain on the primary sounds like a motorcycle if its number 35. I'm not sure about 25.

 

[rybitski]

Thanks for all of the replies! Also, thanks for the compliments .
You guys are absolutely right about the weight now that I think about it. I was more concerned with keeping things balanced from side to side that I didn't even take into account the center of gravity.. What if I moved them down to just above the axle and have one on either side? This is the only other place I can think to mount them (kinda like saddle bags). Any suggestions on placement?

 

[amberwolf]

If they wont' fit in the front triangle, then forward of and even with the rear axle on either side is your next best bet. Just far enough back to clear your heels, but not behind the axle.

 

[rybitski]

I have a quick update with some not so good pictures... I am at work now and just have a few photos that I snapped on my phone earliear today, but here it is:

Since I don't have any bike specific tools a vise is what I had to use while welding the rack to the frame. Since I amusing a junk bike that is already scratched, I am not to concerned about messing up the paint. It was very convenient to have the bike at standing height while welding the rack on, it made my life alot easier.

This is another not so good picture of one of the welds connecting the rack to the rear swing arm of the bike. It is not the prettiest weld, but in that tight space it is kind of hard. I had the amperage turned up so there is a pretty decent penetration, i.e. that weld isn’t breaking. I sanded part of the paint off where the welds were going to be, but the heat made the surrounding paint bubble up. I will have to sand this later and give it a good coat of paint to prevent rust.

I will get some better pictures later, but this is all I have at this time. Today was the last day that I had access to the scene shop for personal use. Classes start Monday and so does the build for the first show. Luckily I got to go in there and finish up my welding for the most part. I got my batteries in the mail today as well as the 36 hole flip flop hub. I am planning on going to my LBS and lacing it up tomorrow. The guy who runs the shop is really helpful (unlike some horror stories I have read on here). That isn't to say he skeptical about the contraption I am explaining to him, but he is happy to help. He actually thought me how to spoke a tire a few weeks ago and is letting me use his truing wheel.

 

[TopCat]

You are going to add support struts from your motor frame down to your rear dropouts? Other wise your frame is going to flex and bend once your motor spins up. Mine still flexes a little but then im not using as thick a metal as your are....

I have my batts slung low in my frame....

Since these pics were taken I have added a piece of wood to the frame to hold the battery that sits under the seat plus a couple of metal struts off the frame to the mudguard fixing holes under the seat. This makes my motor frame more ridged.

Regards
Tom

 

[rybitski]

Yeah I will add supports that will attach on either side of the rear axle. There are 2 threaded mounting holes on either side that I plan on using.