Changing crankshaft gear

[wings02]

I have read the issues of changing the hub gear in a Sondors Fold XS bike. Changing the high gear as referenced by a forum member has caused slight rubbing on the frame. Has anyone changed the crankshaft gear instead of the hub gear?
If so, what size (tooth) gear could I use without having to get a longer chain? I am trying to solve the problem of "running out of pedal" when I am in level 2 and 3 of PAS. If this can be done, could someone reference where to purchase. Thank you!

 

[harryS]

Look at your present chain ring for any spots where a larger diameter chain would interfere. On some bikes, it's the tubing behind the pedals, On my Schwinn folder, it was the hinge in the frame that limited me to 52T.

Look for a square taper chain ring. If your Sondors uses a chain that bolts onto the crank, you could just get the gear, but this is not common on inexpensive ebikes, You'll probably buy the gear with the crank arms, Yes, you can buy them on amazon. 52T, 54T, and 56T are common,

I went from a 38T to a 52T on one bike, and the chain was long enough, but that's unusual. So you buy a chain tool and another chain. You will also need a crank tool to pull the gear,