How to Locate Your Electric Bike Serial Number
Your e-bike serial number is almost always stamped into the metal frame. Start by checking the bottom bracket (the area where the pedals and crank arms attach) — that’s the most common spot. If it’s not there, inspect the head tube (where the fork meets the frame) or the rear dropouts on the back of the frame. Most electric bikes place the serial number in one of these three locations.
Common Serial Number Locations on Electric Bikes
The easiest way to find the number is to flip the bike over or prop it against a wall so you can see the underside of the frame. Use a flashlight if the engraving is shallow or painted over.
Bottom Bracket Area
Look on the flat section of the frame directly behind the crankset. The number is typically engraved into the metal or applied as a sticker that is later clear-coated. On step-thru frames, this spot may be partially hidden by the motor or battery mount — slide a mirror or phone camera under the bracket to view it. Mid-drive motors (e.g., Bosch, Shimano, Bafang) often cover this area; remove the battery and look from below with a bright light.
Head Tube
On many step-thru and cruiser e-bikes, the serial number is on the front of the head tube, just above the front wheel. On full-suspension models, check the back of the head tube instead. If the number is covered by a head badge, gently pry the badge off at the edges (it’s often held on with double-sided tape) and look underneath. Reapply the badge afterward to protect the number from moisture.
Rear Dropouts
Turn the bike so the drive side (chain side) faces you. The serial number may be engraved on the rear dropout — the flat metal plate where the axle sits. This is common on older hub-drive models. Clean chain grease off the dropout with a rag to reveal the numbers. If the engraving is worn down, wipe the area with a solvent-free degreaser and let it dry before trying to read it.
Motor Housing (Hub-Drive Models)
If your e-bike has a rear hub motor, the motor casing may carry its own serial number separate from the frame number. The frame serial number is still the primary one for registration and theft reporting. Do not confuse the two — the motor number is usually longer and includes a manufacturer prefix like “MOT-” or “H-”. If you only find a motor number, keep searching; the frame number is likely elsewhere.
Battery Tray or Downtube
Some mid-drive e-bikes (especially from Bosch or Shimano systems) stamp the serial number on the top of the bottom bracket shell or on the underside of the downtube near the battery cradle. Remove the battery and look in the tray for a sticker or engraving. On some models, the serial number is also printed on a sticker inside the battery slot; if that sticker is peeling, the number may still be readable by sliding a phone camera in.
Step-Thru and Folding Frames
- Step-thru: Check the head tube, the rear dropouts, or the underside of the top tube (the bar that runs between the seat and head tube). On some step-thru frames, the serial number is on the inside of the chainstay near the bottom bracket.
- Folding e-bikes: Serial numbers often appear on the folding hinge mechanism or on the inside of the seat tube. If your bike has a hinge latch, open it and inspect the metal faces. The number may also be stamped on the hinge pin plate itself.
How to Verify You Found the Correct Serial Number
Once you locate a string of characters, confirm it’s the frame serial number before using it for registration or theft reporting. The frame serial number is usually 6 to 17 characters long and may include both letters and numbers. It should be unique to that frame. A manufacturer’s label that only says “Model X123” or “Product Code” is not the serial number — look for a longer code without a product name.
Verification check: Enter the number into your e-bike brand’s online registration portal or warranty lookup tool. Most major manufacturers (Bosch, Shimano, Trek, Specialized, Rad Power, etc.) have a VIN/serial lookup page. If the system accepts the number and returns your bike’s model and year, you have the correct serial. If it returns “not found,” double-check for a misread digit — common mistakes are confusing 0 with O, 1 with I, or 5 with S.
If you don’t have online access: Compare the number with the one printed on the original purchase invoice or owner’s manual. Many dealers write the serial number on the receipt at time of sale. If you have a registration card from the manufacturer, the number should match exactly.
When You Can’t Find the Serial Number
If the area is painted over, try rubbing a crayon or soft pencil over the surface to reveal raised digits. For stickers that have worn off, check your owner’s manual or the original box — many manufacturers include the serial number on the purchase invoice or in an online account after registration. If the frame has been repainted, contact the e-bike maker with the model name and year; they can often provide the correct serial range for your frame based on the production date.
If the number is physically damaged (e.g., scratched, corroded, or partially faded), photograph the area with a macro lens or a phone camera at maximum zoom. Send the image to the manufacturer’s support team — they may still be able to reconstruct the number from the remaining digits or match it against production records. On some hub-drive e-bikes, the motor serial number can be cross-referenced with the frame serial in the manufacturer’s database.
Secondhand bikes with no visible serial: This is a red flag. A missing serial number can indicate a stolen frame or one that has been deliberately removed. Before purchasing a used e-bike, ask the seller for a photo of the serial. If they can’t provide one, run the visible numbers (motor, display, any stickers) through databases like BikeIndex.org or Garage 529 to check for theft reports. If the serial is truly gone, you can still ride the bike, but insurance companies and many police departments will not accept a theft claim without a frame number. Some states also require a serial for legal registration of Class 2 and Class 3 e-bikes.
Last resort: Contact the manufacturer with the model name, motor serial (if visible), and any other identifiers you have (color, year, wheel size, battery type). They may be able to issue a new frame number or confirm the original digits from a production record. A small engraving shop or locksmith can then restamp the number into a non-structural area of the frame (with manufacturer approval), but this is rare and usually only done for custom builds or lost-title cases.
The serial number is your e-bike’s primary identifier for registration, warranty claims, and theft recovery. Taking a photo of the number and storing it in your phone’s notes or a cloud folder takes two minutes and can save you hours later. If you ever sell the bike, include the serial in the bill of sale to protect both you and the buyer.
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Ryan Williams has spent over 8 years testing, repairing, and writing about electric bikes. He has personally ridden and reviewed 150+ e-bike models from brands like Lectric, Aventon, Rad Power, Super73, and dozens more.
Before founding EBIKE Delight, Ryan worked as a bicycle mechanic for 5 years at independent bike shops across California, where he specialized in e-bike conversions and electrical system diagnostics. He holds a Certificate in Electric Vehicle Technology from the Light Electric Vehicle Association (LEVA).
Ryan’s work has been cited by Electric Bike Report, Electrek, and BikeRumor. When he is not testing the latest e-bike on California backroads, he is in his workshop tearing down batteries and controllers to understand what makes them tick — and what makes them fail.
Areas of Expertise
E-bike performance testing and real-world range verificationBattery diagnostics, charging best practices, and safetyBrand comparisons: Lectric, Aventon, Rad Power, Super73, and moreError code troubleshooting across major e-bike systemsE-bike laws, registration, and compliance by state
Ryan believes every rider deserves honest, hands-on information — not marketing hype.