Aventon Sinch.2: bike speeds up on its own (official recall and free fix)

Your Aventon Sinch.2 folding e-bike surges forward or speeds up when you didn't ask it to. This exact symptom is the subject of an official safety recall. CPSC and Aventon list a recall of Class 2 Sinch.2 folding e-bikes with a 500W motor sold in 2023, because the bike can accelerate unexpectedly, which can lead to loss of control and a crash (CPSC recall notice, Aventon recalls). Short answer: stop riding it and have an Aventon authorized dealer install the free controller software update.

Most likely cause

The recall remedy is a software update to the controller, which tells you the fix lives in the controller's programming rather than in a part you can adjust at home (CPSC recall notice). Aventon's recall page describes the repair as a free software flash done at an authorized dealer (Aventon recalls).

Other causes to rule out

These won't make a bike speed up on its own the way the recall describes, but they can make power feel erratic, so mention them to the dealer:

• A throttle that doesn't spring back to rest. Aventon's Sinch and Level.2 manuals list a loose or damaged throttle as a cause of irregular acceleration (Sinch manual, Level.2 manual). See throttle not working.
• A brake cut-off sensor that isn't sensitive enough, which lets the motor keep running when you squeeze the lever (Aventon brake sensor adjustment).

How to confirm whether your bike is affected

1. Check the frame. CPSC says affected bikes have "Aventon" printed on the side of the down tube and "Sinch.2" on the chain stay, the tube that runs from the rear wheel toward the frame (CPSC recall notice).
2. Check the color. CPSC lists the recalled bikes in Quicksilver (silver) and Sapphire (blue) (CPSC recall notice).
3. Check when it was bought. CPSC gives a sale window from April through August 2023, and Aventon's page gives May through August 2023. If yours was bought in or near that window, treat it as affected until a dealer confirms (CPSC recall notice, Aventon recalls).
4. Neither page lists serial number ranges, so if you're unsure, contact Aventon through its recall page.

Fix options

Get the recall update at an authorized dealer (free)

This is the only fix. Stop riding and book the free repair with an Aventon authorized dealer. Use Aventon's dealer locator to find one, and the recall page for Aventon's contact options. Aventon says it has also contacted known buyers directly (Aventon recalls).

Don't try to fix it yourself (not a DIY job)

The remedy is a controller software flash done by a dealer. There's nothing for an owner to adjust, so don't open the controller.

Parts

• None. The recall repair is a free software update.

When to get a pro

• Any Sinch.2 that may fall in the recall, even if it hasn't surged yet.
• Any e-bike, recalled or not, that accelerates without input. See throttle not working, check brake cut-off and throttle and aventon troubleshooting.

Sources

• CPSC recall notice, cpsc.gov
• Aventon recalls, aventon.com
• dealer locator, aventon.com
• Aventon brake sensor adjustment, rideaventon.zendesk.com
• Sinch manual, cdn.shopify.com
• Level.2 manual, cdn.shopify.com

Stuck after these checks? Find a shop near you.