Mongoose Bike Serial Decoder

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Mongoose Bike Serial Decoder

Interpreting the Serial numbers and features

on BMX Products, Inc. Frames

Identifying the serial numbers on the early Mongoose frames is actually quite easy and intuitive. For the most part the early Mongoose frames from 1975 and into early 1976 were done with hand stamped 5 digit numbers starting from 10000. For example, a frame from 1975 will have the numbers like 11994.

Oct 18, 2006 Re: Mongoose Serial Number Info oh, i must have misread your question, i was saying that serial number indicates a 82 goose. But if the company says its an 78 repro, then thats what it is, i think that all the repro's were based off the 1978 model. 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.

A feature of an early 1975 frame is the brake tab. The brake tab on these frames is rectangular in shape. Some time late 1975 and onwards it became a single layer of steel, more oval and thinner in shape.

The early 75 coaster brake tab is also thicker and is comprised of two layers of steel welded together

Another feature of an early 1975 frame was the chainstay brace where it connected the seat tube. Note the flared shape of the 75 frame vs the later style (which carried on through all the later years of this frame style) and the extended seat tube.

A further feature was the headtube was offset to extend more to the bottom than it was to the top. It is our guess that it was done this way to allow clearance for the squarer shoulder on Ashtabula forks. This feature carried over for the first few years till the ashtabula forks were replaced with the more rounder style Tange made forks.

In early 1976, the letter C was added to denote Cromo ' During the early production of the Mongoose frames they were made using 1010 steel tubing,when we found problems with the heat from welding and breakage at the weld points they were changed to Chrome Molly tubing. Both frames looked the same but we need some way of determined the difference due to the frames being nickel plated or powder coated paint ,it was impossible to tell the difference in the material for warranty reasons. The letter C was used for chrome molly.' so the serial numbers would look like C17834.

Another feature of an early frame built in 1975 - 1977 was the extra single gusset above the bottom bracket.

In May 1976 the serial number process changed again with the addition of a month code. From here frames were stamped with the letter C for Cromo, a letter for the month, and a number for the year of production. It was around feb/march 77 that the extra single gusset was dropped from the frame.

Of course these are general guidelines in identifying Mongoose frames and there are the anomalies to this process of serial number identification.

The serial numbers were hand stamped on the bottom bracket tubes then packed in (empty beer) boxes waiting to be welded to frame tubes.

The frame components were manufactured in different stages and or departments and some of the parts were exhausted quicker than others, it this process that lead to some of the frames “crossing over” to different years, especially during the end of the year.

RECO (Racer Engineering Company) manufactured frames for BMX Products, Inc. for the first 3 years of production, after that the frames were made “in house” by BMX Products, Inc. RECO was a frame welding company that BMX Products, Inc. used to make their early frames. BMX Products Inc. in the early years moved into the unit next door to RECO and eventually bought them out.

So serial numbers that ran from May 1976 through to March 1981 will have three digits in sequence overtop the serial number of that frame. Let’s look at some serial number examples below to get a better understand how the process worked.

This guideline also applies to Team Mongoose, Supergoose, Jag, Blue Max, Roger DeCoster, Super-X, and Moto-Trac frames.

Each frame had a combination of three key numbers or letters. For example:

CH8 123456
Again, the C stands for Cromoly to make note of which frames were updated with Cromoly. The very early frames were mild steel.

The next letter in the sequence is the month code.
A = January
B = February
C = March
The next number is the last number of the year the frame was produced.
6 = 1976
7 = 1977
8 = 1978
9 = 1979
0 = 1980
1 = 1981
The rest of the serial numbers are sequential and are the number of frames produced in that series.

NB: Super X has an “X” instead of a “C” in the serial number.

The Team Mongoose and Supergoose frames are a little different. The same coding applies to the first part of the serial numbers as we discussed above, however, if a capital T is in front of or above the CXX it indicates that it is a 100% Chromoly frame. The Team Mongoose, Team Minigoose and Supergoose, all should have a T in this area. (Moosegoose, Two/Four, Two/Six, and the Kos Krusier also have 100 % Chromoly tubing).

Another feature of a Team / Supergoose frame is the flattened seat stay where the chain passes it. This was done to give better clearance for the chain. Very early team frames had a 'T' but without the flattened seat stay, but these are very few and were in 1977 mainly. NB: a Supergoose is just a full cromo team frame that has nickel (79/80) or chrome plating (81 onwards) as its final finish. As opposed to a candy coated full cromo frame = team frame. NBB: In 1982 and onwards, a Team frame was also offered in 'Show Chrome' as well as red or blue candy coat. (there are a couple of known Supergoose frames without the flat seat stay.

Serial numbers from 1981

In April 1981 and onwards the frames were coded differently. The 'C' was dropped and they started out with a single letter followed by a sequence of numbers. (nb: The frames were still made in Chatsworth up until 1984 when they moved to Moorpark. This applies to all frames made, EXCEPT those starting with the letter 'M' as these frames were made in the Merida factory in Taiwan.) As before, the letter indicates the month and the first number or the second digit in the sequence indicates the last number for that year. Also of note is the 'T' (for team), was also dropped. When they dropped the 'C', it was realised that there was no need for it, as there were other ways to ID a Team/Supergoose (full cromo) frame. There was a few 'crazy' months around April, May and June in 1981, when there was mix of old and new dropouts being used. So there is actually a month or more where there was a 'Team/Supergoose' frame that had no 'T' in serial but still had 'old style' dropouts....

The easiest way is to check the brake bridge for the extra two slotted holes that were added. These extra holes were only on the full cromo frames that had the 'step down' type dropouts. (If your frame has holes in the dropouts, BUT does not have 3 holes in the brake bridge, its NOT a supergoose, even if its chrome) See dropouts page here.

J2009981: according to this serial number the frame was manufactured in October of 1982.

Sometime in 1982 the bottom bracket brace was replaced with an open design (see picture below). USA made frames from post gusset era, still had the month first, then the year but they were stamped not on the bottom bracket but on the brace behind the bottom bracket. All USA made frames after they dropped the “C” were month, then year, then serial number.

As a general rule anything with a Gusset behind the head tube was manufactured in the USA.

There are a few key components to look for on a BMX Products, Inc. frame.

  1. Gusset at the front behind the headtube.
  2. A round hole below the upper seat mast.
  3. Unique Heliarc weld pattern ('heli arc' is another name for TIG. It's proper name is GTAW, or Gas Tungsten Arc Welding. The 'heli' in heli arc comes from the shielding gas helium that was used. )

NON GUSSETT FRAMES (POST 1982 FRAMES)

To start with, any frame with a serial number starting with 'M' was made in Tiawan in the Merida factory. In 1982, BMX Products started to manufacture a new range of non-gussett frame starting with the Pro Class 20' frames. Then next came the first Californian and Expert frames and were USA made, while they were getting setup for Tiawan production. The top of the range frames were USA made, (ie: Pro class, Rupe, Supergoose). USA made frames continued the standard USA numbering. After the company was sold to Service Cycle, it seems all frame production was moved to Tiawan. We have been told that when the company was sold the new owners only wanted complete boxed bikes and the rest of the stock of frames were destroyed.

So to start the decoding of these serial numbers.

  • First Letter = 'M' (Merida factory in Tiawan)
  • First Number = (year of manufacture)
  • Second Letter = (Month of Manufacture) up to feb 1985
  • Second Letter = (Model) only after march 1985 (only for C=cali or E=Expert)
  • Third Letter = (Month of Manufacture) only after march 1985
  • Remaining numbers = serial number of production (NB: these numbers started again from 0 every month)

Here is a typical example.

  • M = Merida (Tiawan Made)
  • 3 = 1983
  • E = May
  • 3533 = production serial number

NB: There are a few anomailes to this, that do show up from time to time. if you are unsure, then email us your pics and serial number.

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.

Mongoose Bike Serial Decoder Number

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.

Mongoose Bike Serial Decoder Tool

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.

Mongoose Bike Serial Decoder Chart

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:

Identify Mongoose Bike By Serial Number

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

Mongoose Bike Serial Decoder Software

A few examples are:

Mongoose Bike Serial Decoder Free

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.

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 Diagram

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.

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