homeless in ca.

I got a folding e-bike with 20 x 4.0 inch tires.

The right pedal was damaged when I got the bike. It eventually worked its way out of the crankarm and stripped the threads. Bike is broken. I've emailed the store asking for a replacement crank and pedal so I can get it running asap. But I want something better.

The stock crank and 46t chainring are a single piece forged together. I have the tool to remove the crankarm. It has a square tapered fastener that's pushed on and held in with an Allen key.

Originally I wanted to replace the chainring with a larger one. At top speed I have to pedal like mad to keep up with the motor. But I ran into the problem that the crankarm and chainring are one piece. So instead I ordered an 11-28t freewheel hub from an online seller. That part has yet to arrive. But now I need to replace the crankarms and chainring anyway. And urgently.

I want to keep the original bottom bracket. The bike is brand new. I'm looking for a crankarm with the same size chainring I had before. But with the option of adding a larger ring for a little more top speed. If I could upgrade from this 1x7 speed drivetrain to a double chainring with a 46t/plus that would suit me even better.

homeless in ca.

Pictures of the new bike

https://www.bikeforums.net/g/album/22428441

homeless in ca.

These are some of the crankarms I'm looking at online.

https://www.aliexpress.com/item/3227...c00dWzbZA&mp=1

https://www.aliexpress.com/item/4000...c00dWzbZA&mp=1

Iride01 

Being an e-bike and also being a folding bike, you should probably find out what the chain line is of your current crankset and pay attention to that when you buy your next crank.

Just put the crank back on and measure from the center line of the chain ring or if multiple rings, then the centerline of the stack to the center line of your seat tube. Measure in millimeters. Though being square tapers, that can sometimes be iffy when the new cranks expect a different type of square taper or even just minor differences of machining from one mfr to the next.

Or check with the mfr of your bike and see if they sell cranks for them or have recommendations for what to get.

JohnDThompson 

Stripped pedal thread in crank arm should be repairable with a helicoil for less than the cost of a new crank. Have you checked with bike shops about helicoil repair?

alcjphil

The first of your choices is a track crankset designed for 1/8" chains. Won't work. Square taper bottom bracket spindles vary in length depending on the crank you choose. Make sure that the one you choose uses the same length spindle as your original crank

homeless in ca.

I tried the crank arms off one of my dumpster bikes and it works. The "new" pedals feel a little short. I got them off a kids mountain bike. It's also a 3 speed chainring and I don't have a derailleur but the bike works again.

The new chainring has 48 teeth instead of 46 and I noticed a slight improvement in my top speed. I also got an email from Canada Post about a package. It should be the 11-28 freewheel I ordered.

I'm gonna wait until I get the new gears and see how the bike does at top speed.