Friday, October 4, 2013

Deciphering 1990-1993 Klein Adroit Serial Numbers

This post is a follow up to my initial write up on the 1990-93 Klein Attitude Serial numbers. The information contained in this post comes from the same database of Klein bikes I compiled in the first place. I now how over 300 bikes in the database to pull from including 70 Adroits (02/11/2015).

1991 Klein Adroit (Revised 02/11/2015)

The Adroit was originally shown in the 1991 catalog and was slated to be available early on that year. Based on anecdotal evidence the bike was late to market and didn't really hit the stores until the middle of 1991. The initial pictures showed the Adroit with a mitered / box crown fork like the 1990 Attitudes (the original Adroit prototype had a fork like this, but no others were made to the best of my knowledge). This may be one of the causes of the delay as that fork was found to be insufficiently strong and was recalled and replaced by the Uniklein fork. It's possible that the development of the new fork and modifying it for the Adroit took longer than accepted.

Main features of the 1991 Adroit:

1. Seat tube is 1 3/8" that necks to 1 1/4" at the top (27.2mm seat post)
2. Carbon wrapped seat stays, chain stays and fork crown
3. Drilled out rear dropouts
4. 2" Down tube
5. Headtube vent holes for top and down tubes sealed with a carbon fiber patch (not on all bikes)
6. Black decals with white outlines (catalog showed solid black)

Carbon fiber patch to seal top tube and seat tube vent holes

Detail of seat tube neck down 

Exposed Boron fibers on drive side chainstay of 91 Adroit

The 1991 series of Adroits all seem to have their serial number stamped underneath the non drive side dropout with the format ADxxx. Like the 1990 & 1991 Attitude the xxx is a HEX number which can be converted into a decimal number representing the frame number. So AD0D2 would be Adroit #210 welded in 1991. Serial numbers were stamped after welding prior to painting. The earlier number I've seen is AD000 (not confirmed visually) which would represent the first production Adroit (this bike came with a box crown fork). The earliest confirmed 91 Adroit is #29 which came with Strata #35. The last confirmed number for 1991 is #343 which still came with the Adroit fork.

Based on those numbers I would imagine that the total number of Adroits made in 1991 was close to 350-375 give or take a few.

1992 Klein Adroit: (PENDING REVISION)

1992 marked the first full production year of the Adroit. The main change this year was the increase in size of the seat post from 27.2mm to 31.6. The same seat tube was used but the neck down was removed since 31.6 seatposts became available. Otherwise the bikes were visually the same.

I believe that like for the Attitudes, Klein abandoned the HEX numbering scheme for The 1992 series of Adroits all seem to have a serial number format of ADTxxxxxx where xxxxxxx is a sequential integer representing the number of the frame as it was welded. So, ADT000330 would be the 330th Adroit made in 1992. This seems to make sense because Klein moved the serial number to underneath the BB shell where they would have more room to use a more traditional numbering system. Also if they continued to use HEX the number of Adroits built would be almost twice as much which isn't supported by the highest number of Strata forks (still using HEX). Unlike the Attitudes which are commonly seen with Rock Shox forks I feel that fewer Adroits came equipped with suspension forks out of the factory. So in theory we should see roughly the same sort of number of Strata forks as frames. Using normal numbers I get a ratio of frames to Strata forks of 1.4 : 1. Using HEX for the frame numbers I get a ratio of frames to Strata forks of 2.4 : 1. Based on my experience, I find it hard to believe that less than 50% of the total MC1 Adroit production came without a Strata fork.

This is only speculation at this point though and I need more data to really confirm these assumptions.

Using the above assumptions the earliest 1992 Adroit I have recorded is #116 (02/15/2015) and the latest one is #399 (02/15/2015). I believe I am missing a lot of data for this year. So my next conclusion would have a larger confidence interval around it. As stated above, I believe that the total numbers i s 1991 were pretty low, around 350-375 maybe. However I feel that 1992 numbers would have been higher than that and closer to 500-550 (02/15/2015). I believe that because some of the earliest 1993 Adroits came with Adroit forks numbering in the low 1000s.

1993 Klein Adroit: (PENDING REVISION)

The 93 Adroit remained basically unchanged from the 1992 model year. The only visual difference was the disappearance of decals and appearance of debossing.

For 1993 Klein introduced a new serial number scheme. The fairly nondescript ADTxxxxxx was first replaced with X for Adroit then MMYY for month and year of production followed by xxxx denoting the number of the frame in the overall production line. At some point Klein added the frame size (19 or 20...) in front of the X.

1993 production started in August of 1992 and the earlier production serial I have is from July and frame #16 with Adroit fork #1109. The latest is from March of 1993 with frame #418 and Adroit fork #1093 (which is funny - they must have built forks in advance).

I would estimate the same sort of production numbers for Adroits in 1993 as there were in 1992 (about 60 or so per month) Perhaps even fewer as Klein was trying to gear up for MC2 production. So I place a total for 1993 around 550-600. Which would mean that the total production of Adroit frames should be somewhere around 1350-1525 maybe.

Once again my data set for Adroits is just growing, 70 numbers is hardly a good data set for an estimated production run of over 1000. I'll continue to refine my assumptions as more data points become available. If you want to help please submit information for your bike or any others that you know of for sure via my blogger contact form.


  1. I have a Klein Quantum road bike that I picked up at the factory in Corvallis WA in the early to mid 1990's (I lived in Seattle and drove there when it was ready.) I can't remember the exact year so I thought to look at the SN and but it only says 0U310. I'm just curious because this is a great bike that I have ridden several thousand miles on over the last 20 or so years and it still rides like it did when it was new. I think aluminum frame cracking is a myth. Do you know anyone who can decode the SN or is there another one I don't see?

  2. I have here a adroit gator with frame number
    Adt 000049 this is a 1992 early one?

    1. Yeah, it's an early 1992 model year bike. So one of the first with a large seat tube. Send me some photos for my records please.

  3. My Adroit gator has a frame # ADOD8, would that make it a 91' or 92'?

    1. That would be a 1991, #216 made that year

  4. I have inherited a Klein mountain bike serial number R5AF9 on rear Any help what model or year.

    1. I believe that would be a Pinnacle, but I haven't done a lot of documentation on that model.