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. 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.
- Okay so I got the serial number for frame that I was trying to find out the model and stuff but what do I do with it to find that stuff out and there's two btw.
- A while back I spend some time investigating how to read mid-school and new school serial numbers on Mongoose BMX bikes. After 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.
- I have an old Mongoose 'Supergoose' with the serial number H151413. I have been told that number is strange. Dose any one know why or how I can read it? Thanks Original Mongoose. Jun 9 2005, 09:43 PM. On the later bikes that start with M, I believe the second number is the year and the 3rd letter is the month it was manufactured.
A while back I spend some time investigating how to read mid-school and new school serial numbers on Mongoose BMX bikes.
Sep 22, 2010 1161= the serial number of the frame. This can be as short as one digit, ie, 911 for Sept, 1981, frame number 1. D= Darrell Kendell, the man who actually built the frame in the factory. Other code letters used as a suffix are. M= Mark Bradley who was a frame welder, a designer, test rider & Factory Team rider. R= Ray Williams.
After 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.
It didn’t take long to realise there were many similarities when looking at GT serial numbers and Mongoose serial numbers. The placement and sequence of the numbers is stamped in the same place under the bottom bracket. Many of the GT serial numbers start with the same letter sequence. 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. 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. 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. Anyway that’s a post for another time.
As 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.
Of course there are also many variations in GT serial numbers and I have focussed mainly on cracking the new-school numbers for now. That is bikes made between 2000 and 2010, and those bikes made in the Taiwan factories with specific serial number sequences. There will be bikes that are different, if you have any examples of where this crack doesn’t work, add a comment below.
GT serial numbers are usually found stamped on the bottom of the bottom bracket of your BMX. This is not always the case and there will be some bikes that do not fit into this formula.
For 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. The 3rd letter corresponds to the year of manufacture.
1991-2000 – 4 letters at beginning, 3rd is year
A B C D E F G H I J
91 92 93 94 95 96 97 98 99 00
91 92 93 94 95 96 97 98 99 00
The 4th letter indicates the Month
A B C D E F G H I J K L
Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec
Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec
A few examples are:
HFGB00000 – 4 letters, GB are the dates. G is the year (1997), B is the month (Feb)
HFBH00000 – 4 letters, BH are the dates. B is the year (1992), H is the month (Aug)
For new-school GT BMX bikes built through most of the 2000’s with a serial number that begins with 5 letters. The 4th letter corresponds to the year of manufacture and follows on from the mid-school serial numbers.
![Serial Serial](/uploads/1/2/6/3/126304184/837812599.png)
2001-2010 – 5 letters at beginning, 4th is year
K L M N O P Q R S T
01 02 03 04 05 06 07 08 09 10
01 02 03 04 05 06 07 08 09 10
The 5th letter indicates the Month
Gm Serial Number Decoder
A B C D E F G H I J K L
Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec
Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec
A few examples are:
HAMRF00000 – 5 letters, RF are the dates. R is the year (2008), F is the month (Jun)
HAMOI00000 – 5 letters, OI are the dates. O is the year (2005), I is the month (Sept)
Mongoose Serial Number Decoder Number
Please note: The GT serial number will give you the build date of your GT BMX. Frames were normally manufactured the year before being sold in bike shops. So a build date on a frame of 2003 usually means the bike was sold in stores in 2004.
There is no function for me to reply to comments left on this post.If you have a BMX and don't know what the serial number means. I might be able to help. Go to our Facebook page https://www.facebook.com/rerides.bmx and give us a like! Then upload a photo of your bike and the serial number. We'll take a look and try to help you out.
Chevy Engine Serial Number Decoder
Thanks for reading. If you liked this post, sign up to the blog via email at the bottom of the page and get every post direct to your inbox. For more information on this BMX and more, you canLIKE my Facebook page, to receive regular updates in your feed, visit there-rides websiteor see the rebuilt and restored rides and parts for sale on our eBay store. For more images of all our re-rides in progress follow us on Instagram.