Protect your Brompton — register for free

Register your Brompton

We recommend registering your bike on Bike Index — a free, nonprofit theft protection registry used by police and bike shops worldwide. A registered bike has a real chance of making it home if it's ever stolen.

Register on Bike Index →
1

Create account

Sign up for free on Bike Index — just an email address

2

Add your Brompton

Enter serial number, colour and a photo

3

Ride safe

If ever stolen, mark it and the network helps recover it

Where to find your serial number

Look on the back of your seat tube for a 10-digit number starting with the year and month of production. For example, 1903… = March 2019. On bikes made before 2015, this is a barcode sticker. On newer bikes, it's a small metal badge.

Your frame number is stamped into the metal on the flat section behind the seat tube, near the bottom bracket. It can't be removed or worn off.

Either number works for registration. The serial number was introduced in late 2001 — older Bromptons only have the stamped frame number.

💡 Can't find it? Try a torch — the stamped number can be hard to see in low light. Still stuck? Write to us and we'll help.

Why it matters

When a stolen bike is recovered by police or found by a good samaritan, Bike Index is one of the first places they check. Registration also makes your Brompton much harder to sell on — honest second-hand shops verify against the registry before buying.

Over 750,000 bikes are already registered. It's free, nonprofit, and has been reuniting riders with their bikes since 2013.