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Stolen Brompton Bikes: UK Frame-Number Check (Free, Instant)
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Quick answer
Brompton's stamped frame number is on the bottom bracket shell, on the flat behind the seat tube; a separate ten-digit serial number is on a sticker or plate below the seat, and its first four digits encode the build year and month. Bromptons are one of the most-stolen bikes in UK cities because they fold and re-sell fast, so always run the number through Cyclesite's free lookup before buying.
Where to find a Brompton frame and serial number
The stamped frame number (the identifier stolen-bike databases use) is on the bottom bracket shell, on the flat behind the seat tube. Brompton also assigns a ten-digit serial number, shown on a sticker or plate below the seat, whose first four digits encode the build year and month. Because a sticker can be peeled off, rely on the number stamped into the frame itself.
Why Bromptons are a top theft target
Compact, valuable and instantly portable, Bromptons are stolen and re-sold faster than almost any other bike, especially in London. Brompton can match a serial to its build records, and a genuine owner can usually produce the original receipt or registration. Combine that with a Cyclesite stolen-bike check before paying.
FAQs
- Where is the frame number on a Brompton?
- The stamped frame number is on the bottom bracket shell, on the flat behind the seat tube. A separate ten-digit serial number sits on a sticker or plate below the seat.
- What does a Brompton serial number tell you?
- It is a ten-digit code whose first four digits encode the build year and month (for example, 1903 indicates March 2019). Brompton can match it to their build records.
- Why are Bromptons stolen so often?
- They fold, they are valuable, and they re-sell quickly, which makes them one of the most-targeted bikes in UK cities. Always verify the frame number before buying used.