B is the year (1992), H is the month (Aug)įor new-school GT BMX bikes built through most of the 2000’s with a serial number that begins with 5 letters. HF BH00000 – 4 letters, BH are the dates. G is the year (1997), B is the month (Feb) HF GB00000 – 4 letters, GB are the dates. Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec The 3rd letter corresponds to the year of manufacture.ġ991-2000 – 4 letters at beginning, 3rd is year This is not always the case and there will be some bikes that do not fit into this formula.įor mid-school GT BMX bikes built in Taiwan through most of the 90’s with a serial number that begins with 4 letters before the series of numbers. GT serial numbers are usually found stamped on the bottom of the bottom bracket of your BMX. There will be bikes that are different, if you have any examples of where this crack doesn’t work, add a comment below. That is bikes made between 20, and those bikes made in the Taiwan factories with specific serial number sequences. Of course there are also many variations in GT serial numbers and I have focussed mainly on cracking the new-school numbers for now. Anyway that’s a post for another time.Īs with the Mongoose serial numbers there are many posts from forum members around the world on old-school GT serial numbers, but very little on mid-school or new school. This is probably not true for all of the bikes in either range, but there were a number of bikes that were identical apart from the logo stamping. In fact look closely at many Mongoose and GT BMX’s from the around 2000 to 2010 and you’ll see many similarities in frame design and geometry.

After a bit of digging around online I soon realised that GT BMX bikes and Mongoose BMX bikes were owned by the same company and also made in the same factories in Taiwan. Many of the GT serial numbers start with the same letter sequence. The placement and sequence of the numbers is stamped in the same place under the bottom bracket. It didn’t take long to realise there were many similarities when looking at GT serial numbers and Mongoose serial numbers.

Once you now when the old GT BMX bike was built it’s much easier to find out what model it is and also look at the original parts lists and colours from the bike makers catalogues.Ī while back I spend some time investigating how to read mid-school and new school serial numbers on Mongoose BMX bikes.Īfter buying and restoring a number of older mid-school and new school GT BMX bikes I also need to to figure out how to crack the GT serial numbers to get the same build date information. The first thing everyone wants to know when the buy a second hand GT BMX is ‘how old is it?’ Reading the GT serial number and finding out the build date is an important part of any BMX restoration.

Vintage mongoose serial numbers