SWEET - 5:1 Gearbox With Double Right-Sided Drive

[Deleted Member 4613]

This is my new build, finished which I consider an advancement of the art of motorized bicycles because it has so many benefits over current designs, like the Dax chain drive and the GEBE belted drive. Here's some pics:
Here are the benefits:
1. Low cost gearbox
2. Motor close to tire for better balance and look
3. Use of very available 8mm sprockets and chain
4. Double freewheel so riding as a bicycle there is zero drag
5. Easily change out drive sprocket from 11T to 14T
6. Best of all, chain drive for a solid reliable performance in any weather

The red can is my silencer invention, which I will soon test.
I am considering putting this complete unit out as a kit, if there is enough interest.
Bicycle is the Schwinn Riverside, and the motor is the Tanaka 32cc PF-3300, which I bought for $89.00

 

[Deleted Member 4613]

Had to make an improvement: Reposition the motor mount, align the chain better. The chain was coming off, not aligned well enough, but all good now. May make a vid. The Tanaka motor just purrs along. Great motor, very quiet with my silencer, and practically no smoke. I used sta-mix semi-syntheic 2 stroke smokeless oil. It works.

 

[Silvaire]

Some clever "out of the box" thinking with your build, Mike.

I especially like your quick access polyethylene chain guard design!

 

[loquin]

Yes... First place in the "Most Innovative Use of Tupperware" category, LOL

 

[lowracer]

@Deleted Member 4613,
Install looks great & really like the freewheeling aspect...
-lowracer-

 

[wheelbender6]

I'm a die hard frame mount guy, but I dig your rack mount. The way you positioned the engine lower, like a friction drive, makes a big difference.

 

[loquin]

How many teeth on the driven sprocket ?

Plus, it looks like #35 chain?

 

[Mike S]

I used a 54t on the driven but it is an 8mm chain.

 

[Stoney]

I am about to mount this as an axle mount on the rear Lt side (5.1 gear box). When I talked to duane (thats dax he said to get 72t sprocket and 14t for best overall and 11t for pulling trailers cargo or 20t for speed) is this correct? It seems to me mike with his set up this wouldn't be accurate!!! Who would be correct? they are both using the same motor sprockets but different wheel sprockets and claiming the same results... I honestly don't know how to calculate the correct figures and duane insists from experience that he is correct. Fyi- I didn't see this until after talking to Duane and was about to buy my parts. Now I am confused. I am looking for the best gear ratios for torque and speed 20-25mph or 23-28mph for my particular engine the tanaka 3300 - The same one mike has.
Thanks in advance

 

[Deleted Member 4613]

OK, here's how I made the speed/gear calculation. I have a 54 tooth 8mm sprocket connected to an 11 tooth sprocket on the gearbox. Using the speed calculator here, http://www.diygokarts.com/speed-calculator.html I simply put this in the calculator and it comes out to 110 mph, then divide this by 5 (the gearbox ratio) and the result is 22 mph. Here's some numbers based on the calculator:

wheel sprocket, gear sprocket, speed
72 14 21
54 14 28
54 11 22

I used a 54T because I had one, and it is readily available. Don't know if a 72T 8mm sprocket is available.
So 72/14 is very close to 54/11. This should help.