gear ratios for weed eater bike

[keatonx]

I have a modified gearbox that does 3.5:1. That has a 9 tooth SBP sprocket that goes to a 40 tooth bicycle sprocket. It does 4.4444444:1.

 

[5-7HEAVEN]

Well, you could have two rear wheels and sprockets, one with a larger sprocket for offroad.

 

[keatonx]

Maybe but it has pretty ghetto tires it would be hard to find wheels witth those tires.

I checked my ratios and the drill gearbox+chain would only do about 13.5:1.

I just really have no idea how to set up jackshafts, and i need to keep the pedals for legalty. So what I think I'm gonna do is quickly slap on the 13.5:1 with cable ties and duck tape,and see how it goes. THEN i will se what I'm gonna do.

 

[5-7HEAVEN]

Good Idea!

Yes, right it like itis and see if that's how you like it.

 

[keatonx]

My bike is actually frame mount now (wooden rack didn't work out so well), but the only difference in the drivetrain is the gearbox. The old one was from a cordless drill, and now it's from an angle grinder, so now the engine can be mounted with the crank parallel with the frame. It goes about 60kmh, and I'm adding a 3 speed pedal crank to the rear wheel, and a pocket bike clutch.
The gears are tricky, because the derailler is for the right side, and the chain is now on the left. but Iwill get tons of speed and torque with the 3 speed.

 

[5-7HEAVEN]

Great!

I can't wait to see it run!