Where is My Bicycle Serial Number? (How to Find & Read It)

Whether you’re registering your new ride for a warranty, filing an insurance claim, or—hopefully not—reporting it stolen, you’re going to need your bicycle’s serial number.

Unlike a car’s VIN, which is usually in a predictable spot on the dashboard, bicycle manufacturers hide serial numbers in several different places.

In this guide, I’ll show you the 5 most common locations to find your bike’s serial number and what to do if you still can’t find it.

The 5 Most Common Locations

1. The Bottom Bracket (Under the Pedals) - 80% of Bikes

Flip your bike upside down. Look at the “shell” where the pedal arms (cranks) spin. This is the Bottom Bracket.

Most manufacturers engrave the serial number here. It might be covered in a layer of grease or road grime, so grab a rag and wipe it clean.

2. The Head Tube (Front of the Bike)

Look at the front of the frame, between the handlebars and the fork. Some brands (like older Schwinns or vintage road bikes) stamp the serial number right on the front or side of the head tube.

3. Rear Dropouts (Near the Chain)

The dropouts are the metal slots where the rear wheel axle attaches to the frame. Check the inside or outside face of both the left and right dropouts.

4. The Seat Tube (Near the Bottom)

Some modern carbon fiber frames use a sticker or an engraved plate on the back of the seat tube, just above where the cranks attach.

5. Part of the Chainstay

The chainstays are the tubes that run horizontally from the pedals to the rear wheel. Occasionally, the serial number is stamped on the underside of one of these tubes.

How to Read a Serial Number

Most serial numbers are a string of 6 to 12 alphanumeric characters. While every brand is different, they often follow this pattern:

• First Letter: Usually the factory or country of origin.
• Next Two Numbers: Often the year of manufacture (e.g., “23” for 2023).
• Remaining Numbers: The unique production sequence for that specific frame.

Tip: If the number is hard to read, take a photo with your phone and use a “zoom” or “invert colors” filter to make the engraving pop.

What to Do if There is No Serial Number?

• Custom/Carbon Frames: Some high-end carbon frames only have a barcode sticker. If this falls off, the serial number is gone. Check your original purchase receipt or owner’s manual.
• Re-Painted Frames: If a bike has been professionally powder-coated or spray-painted, the serial number might be buried under the paint.
• Stolen/Altered: If the serial number looks filed down or scratched off, do not buy the bike. This is the #1 sign of a stolen bicycle.

Bicycle Serial Number FAQ