Description
This is a 140mm square-taper crank arm set for single-speed cargo e-bikes, sold as the left arm, the right arm with its 28-tooth chainring attached, or both sides together. It’s a direct-fit replacement for the standard crank arms fitted to Vinxs and similar 20-inch cargo e-bikes, useful if you’ve bent an arm, stripped the chainring teeth, or are building up a spare.
Key Features
- 140mm length, laser-marked on the arm for easy confirmation
- Square-taper spindle interface — one of the most common bottom bracket standards
- Right arm includes a riveted 28-tooth chainring on a 5-arm spider
- Left arm supplied plain, ready for your existing pedal
Perfect For
- Replacing a bent, cracked or worn crank arm on a Vinxs cargo e-bike
- Replacing a chainring with worn or damaged teeth
- Workshop rebuilds and spare parts stock
- Riders who only need one side and don’t want to pay for a full set
Product Information
- Length: 140mm
- Chainring: 28 teeth, 5-arm spider (right side only)
- Spindle interface: square taper
- Sold as: left only, right with chainring, or both sides
Compatibility
This crank arm is designed for Vinxs electric bikes and similar 20-inch single-speed cargo e-bikes using a square-taper bottom bracket. Square taper is a widely used standard, but pairing the wrong crank length or chainring tooth count with your bottom bracket and chain can affect gearing and ground clearance — if you’re not certain your bike matches this spec, send us a photo of your current crank arm (including the length stamp) and we’ll confirm before you order.
Installation Notes
- Crank arms mount onto a square-taper bottom bracket spindle and are secured with a crank bolt or nut — a crank puller is needed to remove the old arm
- If replacing only one side, match the new chainring’s tooth count and chainline to your existing chain and rear sprocket
- Torque the crank bolt to the bike manufacturer’s spec — an under-tightened crank arm will work loose and damage the square-taper interface over time
Workshop Tips
If your existing chainring teeth are visibly hooked or worn but the crank arm itself is straight, you can order the right-side crank with chainring on its own rather than the full set — most riders only need one side replaced. Bring the bike in and we can confirm fit, check chain wear at the same time, and fit it properly with the correct torque, rather than guessing at home.
Will this fit my Vinxs cargo e-bike?
Yes — this crank arm and chainring are sized for Vinxs and similar 20-inch single-speed cargo e-bikes with a square-taper bottom bracket. If you’re unsure, send us a photo of your current crank arm and we’ll confirm before you order.
Do I need to replace both sides?
No — you can order just the left arm or just the right arm with chainring if only one side is damaged. The “Both Sides” option is there if you want a matched pair or are doing a full rebuild.
What tools do I need to fit it?
You’ll need a crank puller to remove the old arm and a socket or crank bolt tool to torque the new one on correctly. If you’re not confident doing this yourself, our workshop can fit it for you.
Is the chainring replaceable separately from the arm?
On this crank, the chainring is riveted to the right-side arm as one assembly, so the right-side option replaces both together rather than the chainring alone.
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