All bikes 1 all have unique serial numbers.
Most bicycles have their serial number engraved beneath their bottom bracket, but sometimes serial numbers are found in other places. Here are some examples of where and what to look for:
The bottom bracket (where serial numbers are typically located) is circled.
A serial number on the underside of a bottom bracket.
Another serial number beneath the bottom bracket, aligned parallel to the frame.
Some Schwinn bicycles have the unique identifying number on their head tube (which is on the front of the bike).
A serial number located on a rear drop out. Some BMX bikes and a few Schwinn bicycles place the serial on the rear dropout. On older Schwinns there are numbers stamped on both the drive side and non-drive side rear dropouts; the one on the non-drive side dropout is the serial number.
Some bikes have multiple serial numbers. 2 When adding a bike to the Index, it's best to enter all the groups of numbers and letters separated by spaces.
Hopefully you can find the serial number on the bicycle you're looking at, email firstname.lastname@example.org if you're having trouble.