something i have always wondered

why doesn't anyone take the sprocket(s) and derailer off a ten speed bike and put it on their moped? or i suppose you could just put the whole wheel on if you cant get just the sprocket on, but then you would have to rig the brakes.

Would i be wrong in saying it would go alot faster?

Re: something i have always wondered

If you swapped added the 5 speed freewheel and a derailleur you could pedal faster/ easier. Swapping the whole wheel wouldn't be a great idea as you'd have no good way to mount the drive sprocket, it would be weaker and you'd have no way for good brakes. BUT, you could pedal it pretty fast!

Re: something i have always wondered

The whole setup can't handle the stress, it would work if you really babied it, for a little while at least. My dad built a moped out of a Schwinn 3 speed back in the day, it tore up the gearing in that little hub.

Re: something i have always wondered

Zachary Evans, Destroyer of Worlds /

Mopeds do not work that way!

Well.. they do, or would.. but um..

I think it would be a bad idea to do it on the drive chain, there's definatly a reason motorcycles don't use derailers..

As far as the pedal side, you'd have to fab up a new swing arm, but it should be doable.

And using a bike rear wheel (especially axle), isn't a safe idea...

I'll admit the thought of adding gears so that I could assist my moped at higher speeds has crossed my mind, but.. I dono, just not something I thing I'd want to do to my bike.

Re: something i have always wondered

Some mopeds have a humungous dirt bike rear sprocket and a tiny front sprocket and they just look like governors to me. I doubt most mopeds get half of their moneys worth out of 50cc. i think its weird how they are designed to be slow. I dont see why the derailer wouldn't work but i never understood how they worked in the first place.

Re: something i have always wondered

I don't have a bicycle with a derailleur, so I may be wrong, but don't you have to stop pedalling when you slide over to the next gear, or at least slack off? You'd have to be modulating tour throttle all the time. Also, on a moped, when you let off the throttle, you get braking from the engine, which stresses the lower length of the chain, and I don't think the derailleur could handle that well.

Besides, a moped engine will only get a bike up to a certain speed, depending on its power. Higher gears won't give you more speed, just lower revs at that speed. It might help acceleration, though.

If I were going to put "gears" on a moped, I would use a Nuvinci hub:

http://www.fallbrooktech.com/NuVinci.asp

Very cool.

Re: something i have always wondered

I'm not an engineer but that doesn't sound right.

So higher gears wouldn't give more speed? If the revs are lower at that speed, why wouldn't the revs get higher?

Re: something i have always wondered

not enuf power

Re: something i have always wondered

and gears will shred but other than that should be fine and if u got a thicker chain it would eat up your thing that moves the chain from gear to gear and if u got that thick enuf then it would shred your chain then a thicker chain would make u go slower even with the gearing u would see very little increase any where because of added weight

Re: something i have always wondered

It takes power to make a moped move, and more power to make it move faster. A small engine has a very narrow powerband (the rpm range where it makes the most power). Thats where a transmission comes in, so you can keep the engine in it's powerband at different speeds. But you can still only go so fast, no matter how many speeds you have, because you run out of power. A vehicle, moped or otherwise, is constantly accelerating, just to overcome wind resistance and rolling friction, but only to a point. Get on your bicycle, and see how fast you can go. Higher gearing will help to a point, but eventually you simply run out of power. A manual transmission would be a great addition to a moped, but it would have to be an internal motorcycle type transmission. Bicycle transmissions will not work with the speed and power of even a stock moped. I have destroyed several derailleurs on my mountain bikes, with no motor. Even a top of the line Shimano XTR. Peace. Jerry.

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