My name is Kenny and I am a motorized bicycle addict

streetstrip80

streetstrip80

New Member
A friend left his kit at my house, because he was working on a build, so I used it to mock up this wee chop. I had been holding on to these forks since I found them because I had this build in my head.
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20" rear 18" front 30 T sprocket (which I have found works well with a 20" wheel)
 
Re: My name is Kenny and I am a MB addict

Welcome, keep coming back, it gets worse, if you stick around.
I guess this is your prototype chopper, Looks cool to me.

Peace Crazy Horse.
 
Re: My name is Kenny and I am a MB addict

That's pretty radical looking I like it!! You came to the right place for Motor Bikes Anonymous. Only thing is we are not a gonna ween you from the addiction here.:D

Welcome to the forum(^) Your gonna fit right in hope you enjoy it as much as we do!
 
Re: My name is Kenny and I am a MB addict

You bet. We just feed the habit. That bike is looking fine.

Steve.
 
Re: My name is Kenny and I am a MB addict

Love the single spring fork setup! That's one I haven't seen. Come on, enjoy your fix!!!

Also that bike makes your engine look huge!!! Or at least that's what she said, ba dum bump tchhhh.
 
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Re: My name is Kenny and I am a MB addict

Welcome to the forum. Interesting build you have there. Does the wheel in front being smaller make much difference in how it handles? I ask because I'm fooling around with a 1980 AMF Roadmaster moped with 16" wheels, drum brakes and suspension fork. China girl fits fine, all is good except figuring out how to mount the driven sprocket in back. The drum hub is big, five inches in diameter and has no sprocket on the engine side since it was a friction drive setup when it was a moped. But looking at yours I can see that a 20" wheel would fit fight in there and I could do a rag joint with a smaller sprocket. So, I may try that. I'm looking for around 25 mph cruising with some hill climbing power... do you think a 36" sprocket would do it? Where do you find a 30T sprocket? And what kind of top end does that give you?
SB
 
Re: My name is Kenny and I am a MB addict

silverbear said:
Welcome to the forum. Interesting build you have there. Does the wheel in front being smaller make much difference in how it handles? I ask because I'm fooling around with a 1980 AMF Roadmaster moped with 16" wheels, drum brakes and suspension fork. China girl fits fine, all is good except figuring out how to mount the driven sprocket in back. The drum hub is big, five inches in diameter and has no sprocket on the engine side since it was a friction drive setup when it was a moped. But looking at yours I can see that a 20" wheel would fit fight in there and I could do a rag joint with a smaller sprocket. So, I may try that. I'm looking for around 25 mph cruising with some hill climbing power... do you think a 36" sprocket would do it? Where do you find a 30T sprocket? And what kind of top end does that give you?
SB
Click to expand...

I just noticed I said 18" front, it is actually a 16". I may change it to an 18", because this thing has almost no trail and its a bit scary at speed.

Not sure exactly what you are asking about the size. If you mean that the front is smaller than the back, i dont think this alone afects handling. Changing the sizes will change the rake and trail though, and this should be considered.

As for the gearing, circumference is proportional to diameter so it is easy to get a conversion factor.
ie
26/20=1.3 so
a 20" wheel with a 30 tooth sprocket will ride like a 26" with a 30x1.3=39 tooth sprocket
or
a 20" with a 36 tooth will ride like a 26" with a 36x1.3=46.8 tooth (I dont think a chain would like a 46.8 tooth sprocket but you get the idea)

I disected a mountain bike front sprocket to make my 30 tooth. At that time I did some gps speed testing, but I do not remember the #s. What I do remember is that I chickened out before the motor rapped out with the 30 tooth on a 27" road bike wheel.

Good luck and Happy Trails
Kenny
 
Re: My name is Kenny and I am a MB addict

Thanks, Kenny.
You've given me some things to think about. Thanks to a suggestion from Corgi I measured the diameter of the moped wheel and discovered the 16" is a measurement of the rim, not the whole wheel with tire. With the tire taken into consideration it is a little bigger than 20" which would make a 20" wheel in back a nice match. I'll go that route unless I can figure a way to mount a sprocket to the rear moped wheel.
SB
 
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