rear pedal sprocket size?

Leila Bozorg /

Working on my first moped and stuck: what do I need to consider when trying to return a no-ped into a moped, particularly when it comes to rear pedal sprocket size? I've seen a range of 16T-24T on rear sprockets. Does the # of teeth need to match the # on the pedal crank?

Re: rear pedal sprocket size?

You can put any different number of sprocket combos on your bike, though it usually comes down to whether the pedal chain is going to clear the swingarm. I've got a smaller 18t sprocket on my maxi and the chain just barely rubs the swingarm a tiny bit. The smaller rear freewheel allows you to pedal more like a bmx, and less like a 10 speed in low gear.

Re: rear pedal sprocket size?

For rear pedal sprockets (freewheels), it'll depend on the moped. Stock on a Puch is something like 22t (or 20, or 24... I forget). People use smaller ones so they can pedal up to a faster speed, although that does also make it harder to pedal. I think going smaller than the stock size is a good idea since stock pedal gearing is usually pretty worthless, but most people also want something big enough to keep the chain from dragging on the swingarm (but no, it definitely does not need to be the same number of teeth as on the front pedal sprocket). What kind of moped is it?

Re: rear pedal sprocket size?

Leila Bozorg /
lbig OP

Thanks RJ and Linda! Both your responses are super helpful. The frame is originally a sears/puch free-spirit.

Re: rear pedal sprocket size?

I'm pretty sure I've got an 18t on my Free Spirit, and it doesn't rub the swingarm. Or rather, it did at first, but that's only because I was a numpty and I didn't shorten the chain properly. (Chain breakers for pedal-size chain are cheap and very easily found, if you need one). I attached a picture so you can see how it looks on mine.

The 18t does just barely rubs on my Swinger though, exactly like RJ said.

fs 18t.jpg

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