Mongoose Bike Serial Decoder
- Nov 27, 2020 Yet, quite alarmingly, less than 20 percent of bike owners know their bike’s serial number, as Bicycle Law reports. What, exactly, is a bike serial number? A bike serial number is basically a string of digits that will have between six and 10 numbers in it. It is sometimes referred to as a bike frame number.
- Because if your bike is ever lost or stolen, we can provide you with key information that can help you recover your bicycle quicker and easier. The serial number is located on the underside of your bike. Your product was successfully registered @MONGOOSEBIKES.
Secondly, it looks like your building a 1978 model like the John George ad. If your frame is a '79 your looking for a totally different build, see my catalog scans in the museum. A '79 model has annodized 7C's, annodized low flange Shimano hubs with cassette rear, matching red or blue fork, Mongoose suede saddle, MKS BM-1 pedals, Mongoose headset, blue alloy bars and Mongoose shinwall snakebellies.
To properly match a 1978 Team Mongoose like the John George ad and the 1978 catalog you need need MKS BM-1 [again], non logo suede saddle, blue alloy bars, DeCoster fork and believe it or not, the 1978 catalog Team Mongoose has a Motomag decal on the down tube.
Mongoose didn't issue any stamped products [not counting pads] until 1979, then came grips, seats, headsets, bottom brackets, seat clamps and tires.
Team Mongooses came with 39t Shimano rings, both years.
We've talked about the fork already, but that fork looks to be a later model, like 1982/3 when they were putting the red or blue over silver powder coat instead of over nickel, your fork doesn't appear to match your frame shade.
Is the Shimano lever straight or pre-bent? Looks straight, need bent.
What are the date codes on the shimano products, hubs, brakes, cranks? I have the date codes if your as picky as me.
I'll finish with this, I love that bike, as I said I'm building a 1978 just like John's in the ad. I lusted over that ad in 1978/9 like nothing else, I finally got mine in '79 but I always like the 78's better, now I have one. I'm only being picky because I'm nuts about both years, yours, like I said is kind of a cross breed between the 78 and 79.
1975 serial numbers were a hand-stamped five number, individual frame ID. They begin at 10001 and continue until early 1976 when a revised stamp begins to include place of manufacture indicated with the letter 'C' ( for Chatsworth, California) followed by the five number individual frame ID.
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.
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.
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
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
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.
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
The 5th 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
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)
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.
Mongoose Bike Serial Decoder
If you want to know more about the GT BMX you have, visit our BMX Catalogue website. You'll find all the original catalogue info you need including original parts lists, specs, colours and photos of restored bikes.
Mongoose Bike Serial Decoder Tool
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.
How To Identify Mongoose Bikes
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