# Where is the frame number on a Tern bike?

Canonical: https://www.cyclesite.co.uk/trust/frame-numbers/tern
Last reviewed: 2026-06-11

**Quick answer:** On a Tern bike, the Frame Number is a 10 to 13-character alphanumeric code engraved into the frame. Tern says it is either at the bottom of the seat tube or on the bottom bracket, depending on model. The Service Tag Number is different. It is an 8-character code starting with T under a QR sticker.

Tern bikes have two important identifiers: the Service Tag Number and the Frame Number. They are not the same thing. The Service Tag Number starts with a capital T and sits under a QR sticker. The Frame Number is engraved into the bike frame and is the number most commonly used for insurance, police reports and third-party ownership records.

## Find the engraved Frame Number.

Tern engraves the Frame Number directly into the frame: at the bottom of the seat tube on models like the GSD, HSD and Vektron, or on the bottom bracket on models like the BYB and Link.

1. Check the bottom of the seat tube, the upright tube the seat post slides into.
2. If it is not there, check the bottom bracket area between the pedals.
3. Clean away dirt and use a torch. Engraving can be shallow.
4. Look for a 10 to 13-character alphanumeric code.
5. Take a clear photo once you find it.

## What a Tern frame number looks like

The Tern Frame Number is 10 to 13 characters and engraved directly onto the bike frame. The Tern Service Tag Number is 8 characters, starts with a capital T, and sits under the QR code sticker. Useful, but it is not the same as the frame number.

### Not the frame number

- Tern GSD
- Tern HSD
- Tern NBD
- Tern Vektron
- Tern Quick Haul
- Tern Orox
- Tern BYB
- Tern Link
- Tern Verge
- Tern Node
- Tern Eclipse
- Tern Joe
- Bosch motor number
- Battery serial number
- QR code alone
- Service Tag alone
- Accessory serial number
- Rack serial number

## Two numbers, two jobs

The Service Tag and Frame Number confusion is real on Tern bikes. The Service Tag helps with Tern Care, warranty and accessories, while the engraved Frame Number is the reliable ID for third-party registration, insurance and theft recovery.

## Frame Number or Service Tag: what is the difference?

Tern uses both, and they are not the same number. The Frame Number is engraved into the frame and is the reliable ID for third-party registration, insurance and theft recovery. The Service Tag Number helps with Tern Care, warranty and accessories.

### Where to find the Tern Service Tag Number

The Service Tag is usually easier to spot than the engraved Frame Number.

1. Look for the QR sticker near the down tube or bottom bracket.
2. The Service Tag is the 8-character alphanumeric code under that sticker.
3. It starts with a capital T.

### What does a Tern Service Tag look like?

An 8-character alphanumeric sequence starting with T, shown under the QR sticker. Record it alongside the Frame Number, but use the engraved Frame Number for ownership and stolen-bike checks.

## Buying a used Tern

A clean-looking bike is not always a safe buy. Before you pay, ask the seller for a clear photo of the frame number and check it against stolen-bike records. You should also ask for:

- The original receipt or proof of purchase.
- The seller’s name matching the receipt where possible.
- Clear photos of the bike from both sides.
- A photo of the frame number.
- Any service history.
- Details of upgrades or replacement parts.

## Bottom line

On a Tern, the Frame Number is engraved at the bottom of the seat tube (GSD, HSD, Vektron) or on the bottom bracket (BYB, Link), depending on model. Copy the full engraved code, record the Service Tag too, then check it before you buy, sell or register the bike. A used Tern can be a brilliant buy, but the Frame Number is the detail that protects you.

## Frequently asked questions

### Where is the frame number on a Tern GSD?

Tern says the Frame Number is at the bottom of the seat tube on GSD models.

### Where is the frame number on a Tern HSD?

Tern says the Frame Number is at the bottom of the seat tube on HSD models.

### Where is the frame number on a Tern Vektron?

Tern lists the Vektron with the Frame Number at the bottom of the seat tube.

### Where is the frame number on a Tern BYB?

Tern says BYB models have the Frame Number on the bottom bracket.

### Where is the frame number on a Tern Link?

Tern says Link models have the Frame Number on the bottom bracket.

### Is the Tern Service Tag the same as the Frame Number?

No. Tern says the Service Tag is an 8-character code starting with T. The Frame Number is 10 to 13 characters and engraved into the frame.

### What if the Tern Frame Number has been removed?

Do not buy the bike. A removed or damaged Frame Number is a major warning sign and can make the bike hard to register, insure, resell or prove as yours.

### Can I check if a Tern is stolen by frame number?

Yes. Use the engraved Frame Number to run a stolen-bike check before buying. Ask for proof of ownership and check the details match the bike.

### How do I register a Tern bike in the UK?

Find the frame number using the locations described above, then record it against your Tern. It is free, and you need an account so we know where to send the alert. If that exact number is ever reported stolen to us, we email you. If anyone then lists a bike carrying it, the listing is hidden until the seller proves it is theirs.

## Related pages

- Free stolen-bike check: https://www.cyclesite.co.uk/stolen-bikes
- What a used Tern is worth: https://www.cyclesite.co.uk/value/tern
- Stolen Tern bikes: how to check one before you buy: https://www.cyclesite.co.uk/stolen-bikes/guide/stolen-bikes-by-brand-tern
- Used Tern prices by model: https://www.cyclesite.co.uk/value/tern
- Used Tern bikes for sale: https://www.cyclesite.co.uk/bike-brands/tern
- Frame numbers for other brands: https://www.cyclesite.co.uk/trust/frame-numbers

Source: Cyclesite editorial, reviewed 2026-06-11. HTML version: https://www.cyclesite.co.uk/trust/frame-numbers/tern