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GT serial data... this info has become the standard, please refine if need be

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I've been morbidly fascinated with the dearth of GT bikes around here for the past few years.  Now that Kevin is ghost, and sold off a lot of his GT repertoire it seems like we don't really have anyone that goes hard on GT anymore.  Even for freestyle.

 

Well, someone asked for GT serial number info this past summer and there were no replies.  Patrick threw him a bone yesterday, which was cool, but months had passed and the old thread he linked to may not be as informative as what follows.

 

I had a GT as a kid.  I don't have one now. Someday I will.  But to be honest... I haven't been paying a lot of attention because I don't have skin in the game, so to speak, but it's a brand that few would argue is one of the most important in BMX history.  Hence it deserves more attention.

 

So, I looked around and I found that there was an old post on Vintage, that is identical to what they have on the museum - word for word. I think it must have come from the Museum, unless the "museum" he refers to is in fact the museum section on Vintage.  Whatever.

 

Here it is:

 

If the bike frame was manufactured at the Santa Ana CA facility, the first three or four digits of the serial number should be letters abbreviating the model or size of the frame such as "XL", "XXL", CR24, or something like that.

The next part of the serial number is eight numeric digits. The first four numbers should be a two digit month followed by a two digit year.

The last four digits are the serialization digits 0000 to 9999 depending on what number the frame was of the years production.

If the frame was made overseas in Taiwan, it gets more complicated. If the number starts with a K, the frame was made by Kinesis.

That's the only one I remember off the top of my head.

There were at least four companies in Taiwan that made the GT lines :

Robinson, Dyno, Powerlite and Auburn included)

The first digit would be a letter designating the factory that made the frame. There might also be a second letter digit specifying the factory that assembled the bike, if applicable. The model and year of production was also coded by a letter, so you won't be able to spot a two digit month and two digit year.
Before I left, I was writing a specification to standardize all of the serial numbers because GT was starting to send most of its US production to other US fabrication shops. 

The information might also come in handy for deciphering other makes because the factories in Taiwan make bikes for a lot of different companies.
I am tinkering around with the idea of starting to make my own frames, kind of on a "one-off" basis. I am also teaching welding at a local community college.
By the way, did I tell you that the guy ran GT's in house fabrication for the last ten years (he recently retired) was none other than Gilbert Axt. Who? Do you remember Race, Inc.? That was Gilbert. He also did the original PK Ripper for SE Racing. 

and here is the updates, thanks to love thegoose! (Michael S)
well we get a good bit of gt serials that could be identified by the owner, if they only had the tips that some of us have learned, so i will post what i know, and anyone with more knowledge can add to it..so here we go.

here is an example to go by. on the dropout you have "M1" followed by "08922198"..this one is simple.
M1 stands for "mach one" that is your model gt.
it can also be a "I" for interceptor and so on.
next on the serial is "0892" this is easy to decode too,
08 means 8th month, which would be august.
then you have "92" next in the lineup, this would be 1992
the last 4 digits, are your build number, this one would be the 2,198th one built.
Here is another example. if your serial is KGCG2297 this one gets a little complicated. but still easy once you learn the code to it.
the first letter is who made the frame itself, in this case it would be "Kenisis", an overseas company.this could be replaced by another letter but at least we know what that one is there for.

next is the letter "G"..this isnt always there, but if so, this is where it was assembled, (ever notice the built in usa sticker on your gt or dyno?) this is what that letter is there for. it wasnt made here, but was built here.

next is the letter "C"..C is the 3rd letter in the alphabet, and march is the 3rd month, so march is the build month.
next is the letter "G" this is the year. G is the 7th letter in the alphabet,

so this would be a 1987.

here is one more..your serial resembles this:f6030578.
to start, if you have a "baseball" looking stamp behind your serial, this frame was made overseas...no its not a pacific, so dont cry, or get mad...and lets continue. on this serial, the first number is the last digit of the year, so 6 stands for 1986
next is "03"....this is the third month..which is march.
so you have a gt built in march of 1986.

 

this doesnt apply to new gt's, but hopefully some people with info on those will chime in. this isnt always going to match your serial, you may have a "fake"..its not likely but it happens. also on earlier models this can differ. this is for the 2 most popular style serial's i see on here. also, common sense tells you that if you have a suspected "gt" frame, look it up and compare it in the musuem, knowing which style frame you have will help with the process of id'ing your bike with the serial, especially if the serial has some damage that prevents you from getting the full number.

 

on the Vintage thread, MrCoasterbrake added:
 

G5D0166 is a Japanese frame, 1985. i forget if it's the "C" or"D" which represents the month.

some of the above info is only applicable after about 1987ish.

 

 

 

 

If you can improve on this or have a more concise explanation or a chart... by all means, lay it on us.

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What I would add is that in my experience previous to say mid 1982 the serials didn't have a date in them, they were all over the place.  I've noticed this from back in the early 80's when many friends bought GT's around mid 82 into 83 when the month and year started showing up on them.  My frame didn't have a month/year on it.  If the month and year aren't there, prior to them doing so people use the first, second, or third number in the sequence and say, yeah that mean 79, 80, 81, etc. for whatever number 9, 0, 1, 2 happens to be in the sequence of the first three numbers.  This had been of interest to me because I still have my old GT from 81.  I've watched a lot of for sales of early GT's and it's mostly confirmed my suspicions.  But I've kind of gotten tired of arguing the point.  At the end of the day I suppose it doesn't matter as there really is no difference between the 80-83 frames except for the early ones they made with smaller down tubes. 

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Interesting observation!

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I'm hurt. I was hard on GT for a long time, and most people knew that :)

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I was of course joking about the hurt bit :)

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I just purchased a GT Cruiser I'm thinking is early-mid 80's? But the serial number on the dropout is stamped with a 24 and then in a different spot has 221405. So I'm not sure what it is? Anyone have an idea?

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The baseball symbol is the "Koizumi mark of Quality". Koizumi was a very good quality Japanese manufacturer contracted by a lot of the big boys in the early-to/mid 80s. Diamond Back, GT, Hutch and many others.

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SoCal80'sKid, in case you thought Lboorse was replying to you (as I did and was confused by the seeming lack of relevance of his remark in the context of your question) he was not... I had to seek clarification on that. :)  Hopefully someone else might have an answer for you.

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Sorry. Yeah, was replying to original post. I need to catch up... Do you have pics of the cruiser and the stampings?

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There are some interesting early GT frames on ebay right now.  One has the serial number 01801, and the seller is stating that Gary Turner told him this is a Jan. 1980 frame and it's the first one produced that year.  A few others on ebay right now have these serial numbers, 011500 which the seller says is a Jan. 1981 frame, another serial 13449 is being sold as a 1981 because the first number is a 1, while another one with serial 1121581 I believe is being listed as a Nov. 82?  So, my question is why is Gary Turner saying the 01801 is a Jan. 1980 frame when they didn't start putting the full 80, 81, 82, 83, etc. date into the serial number until late 1982?  I'm thinking these early frames just happen to have a zero, one, two, etc. somewhere in the first three numbers and people have been using that low number as the year date.  Anyway, I don't want to put any of the sellers of these frames under a microscope, I'm just trying to point out the randomness of the early serial numbers in determining a definite date of manufacture of these frames. 

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There are some interesting early GT frames on ebay right now. One has the serial number 01801, and the seller is stating that Gary Turner told him this is a Jan. 1980 frame and it's the first one produced that year. A few others on ebay right now have these serial numbers, 011500 which the seller says is a Jan. 1981 frame, another serial 13449 is being sold as a 1981 because the first number is a 1, while another one with serial 1121581 I believe is being listed as a Nov. 82? So, my question is why is Gary Turner saying the 01801 is a Jan. 1980 frame when they didn't start putting the full 80, 81, 82, 83, etc. date into the serial number until late 1982? I'm thinking these early frames just happen to have a zero, one, two, etc. somewhere in the first three numbers and people have been using that low number as the year date. Anyway, I don't want to put any of the sellers of these frames under a microscope, I'm just trying to point out the randomness of the early serial numbers in determining a definite date of manufacture of these frames.

Sounds like he didn't talk to Gary, or Gary doesn't know wtf he's talking about

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I have a bmx frame with serial number that starts with the letter "U".. i think the first four of the S/N is U40U...i cannot find it anywhere in the world on the internet

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post a pic of the frame.  it'll help. 

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I have a gt frame and what is stamped on it is SANP40029 can anybody help me figure out what it is I know it's a performer but don't know what year or where it was made

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Just picked up a GT from a thrift store but can’t find the serial number on the web anywhere. GU2U2469 please help it needs work but would love to restore it. It has a GT TT4 blk winged sprocket. GT seat, pedals and rims. I assume all parts are matching. 

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5 hours ago, David said:

Just picked up a GT from a thrift store but can’t find the serial number on the web anywhere. GU2U2469 please help it needs work but would love to restore it. It has a GT TT4 blk winged sprocket. GT seat, pedals and rims. I assume all parts are matching. 

Pictures would really help out.

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3 hours ago, 05stisilver said:

I just picked up a gt and I’m trying to identify the year and model. Serial is S7KY01800

That’s not an American made gt

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Picked up what I believe is a 98 power series frame, but it is made like a 97 Raider, with straight chain stays. It is aluminum, with 1 1/8 head tube and a serial number of AS00310. I’ve read through several serial number threads and don’t see any that start off like this, or are this short of a number? Frame also looks like it was factory painted silver, and is not ball burnished or polished aluminum. Any thoughts?

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Posted (edited)

Hi I have a gt performer from 87 I think trying to work out the serial number, DS70518812 I think that it’s Taiwan made 1987 in May the other numbers are hard to decipher maybe just production numbers, but I think I’ve got the        factory and year??

Edited by Gary Fell

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Post pics, it definitely helps. 

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On 5/25/2020 at 9:15 AM, Gary Fell said:

Hi I have a gt performer from 87 I think trying to work out the serial number, DS70518812 I think that it’s Taiwan made 1987 in May the other numbers are hard to decipher maybe just production numbers, but I think I’ve got the        factory and year??

Hi.  I just dug out my old black gt performer from my fathers shed after roughly 30 years for my son. After a good cleaning it looks just like I remembered.  He is thrilled to have it.  I am unsure of the year as well but I was thinking 86 or 87.  The serial number is very similar DS70576304.  

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