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Multiple gears on the crankset only to make a 3 speed bike. Possible? How?

I have a bike with an electric motor on the back wheel.
My bike is fixed gear, so it's hard for me to help the motor when pedaling at medium speeds (>20km/h). On the other hand, once I'm out of batteries and I have a hard time going uphill.

I would like make my bike a 3 speed bike without messing with the back wheel.

Is it possible to have 1 gear at the back and 3 gears at the crankset to make my bike a 3 speed?

My idea would be something like a hub gear, but that stays on the crankset instead of the back wheel.


kelseymh1 year ago
Most of the single-to-multiple speed conversions I found on the Web involve changing out the rear hub for a multispeed hub. It sounds like you don't want to (or can't) do that because of the electric motor. I can't see any reason why that's necessary, though. Here's what I would do:

First, replace your crankset with a 3-speed crankset (that's your Google or Amazon search term) and the associated shifting hardware.

You will also need to mount a chain tensioner at the rear hub, since the three gears require different chain lengths. The tensioner should just mount to the frame behind the hub, and not require any wheel modifications.

sevesteen1 year ago
If you've got a true fixed gear (pedals must turn if the wheel turns) I can't help--but if it is a single speed freewheel, there used to be a BMX setup that would work. Single rear freewheel, chain tensioner (basically a rear derailleur but locked in one gear) and a standard front derailleur. The BMX ones used a brake lever for shifting-you would hold the lever for low gear, release it for high.
dkersting (author)  sevesteen1 year ago
Good Idea.
I think this is the way to go.
I may have to make a hole for the front derailleur though.
Do you know where can I know more about this set-up?
Thank you very much.
Kiteman1 year ago
I have no idea how to do that, but I *know* it would be a popular build if you managed it - a geared electric bicycle would be very useful here in San Francisco.
dkersting (author)  Kiteman1 year ago
They sell it already. (http://www.electricwheelstore.com/Electric-Bikes/EW-1600/flypage.tpl.html, for example).
The problem is that in my region geared electric bikes are twice the price of a non-geared.(~1000 USD for a non-geared and at least 2000USD for a geared one).
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