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.

Thursday, October 3, 2013

1990 Klein Attitude final photo shoot

This is what a 1990 Team Klein Attitude is supposed to look like. In a word - classic!

No fancy parts here, just good old fashioned Shimano XT like the man intended. Clean lines, subtle parts that actually work and allow the frame to shine. You really can't do any better than this with this frame!

Yeti ARC-AS Final Photo Shoot

After almost a year of collecting parts, frame repairs, paint, decal recreation and crazy building here is the final product. I didn't expect it to turn out quite to awesome!!!

This bike is completely over the top in every single way. There isn't a single part on here that doesn't have three stickers where one would do, isn't dripping with bright red anodize, or wrapped in delicious carbon fiber. From the prototype HED / Ringle Ti-Stix wheels to the Grafton Speed Controller II brakes and a smatter of other Ringle / Grafton jewlery every part here adds to the show bike look and feel. But this bike doesn't just look the part. All the suspension components, bearing and drivetrain components are fully functional. The suspension travel is tight and the bike feels light and responsive. Although I didn't have a chance to really ride it off road a few quick runs at the local park left me wanting one someday!

Wednesday, October 2, 2013

Deciphering 1990-1993 Klein Attitude Serial Numbers

For as long as I can remember people have been trying to figure out the cryptic Klein serial numbers system used on the early Attitudes and Adroit. Numbers like AT1F3 or ADOD2 left us all scratching our heads. While many owners and even former employees have theorized about what these numbers mean nobody has ever come up with an answer to the scheme.

I'm fortunate to have had more than my share of Attitudes and Adroits roll through my garage and so I decided to set up a small database of numbers and try to correlate those numbers to features which can be attributed to specific periods during Klein production phases. My hope was that I would not only figure out the numbering sequence and be able to determine which sequence came after which and so on.

I've compiled a database of approximately 300 (02/13/2015) serial numbers spanning 1990-1993 Attitudes and Adroits. Here are my findings:

First of all I think Klein used the Hexadecimal numbering system. This would easily explain numbers like 1F3 = 499 and OD2 = 210. This make sense as Klein had been in business for a while and they would have to deal with numbers greater than 999 and since they used the rear dropouts there wasn't enough room for a frame identifier (AT for early Attitudes, AD for early Adroits) and numbers in excess of 999. HEX can express very large numbers by using a combination of letters and numbers. I can't help but wonder if Gary's time at MIT didn't help influence this??

Update 02/13/2015
I've reviewed this with Gary and he confirms that he did in fact use HEX since the very early days. Which explains why even some of the 85 Mountain Kleins have HEX numbers. I've never taken much interest in road frames, but the little bit that I've looked at indicates that those too used HEX numbering for the S/Ns.

1990 Attitude:

The commonly known features of a 1990 Attitude include:

1. Box crown (mitered) fork
2. Solid black decals
3. MC1 headset seal stamped with KLEIN (K) logo

Klein stamped headset cap

The less known features of a 1990 Attitude include:

1. Early Attitudes had the down tube cable inlets rotated up from the centerline
2. Early Attitudes had a 56cm top tube, while later ones increased the length to 57cm
3. Early Attitudes had bottom bracket bearings with red/rust colored seals, later ones had black ones

I believe that early Attitudes started with the ATxxx serial numbers. Each serial number was preceeded by a small Klein logo (K). I've read on old forums that the first batch of Klein Mission Control headtubes were  either undersized or reamed too much causing problems with the bearing fit in the frame (either too tight or spinning). Some Klein employees seemed to remember that once the problem was resolved the serial numbers were changed to BATxxx. I think the change over happened around #302 made as Attitude B(K)AT12E had a B added in front of the (K) symbol implying that the problem was found, fixed and that one frame which originally would have received the bad head tube was fixed and that's why the B was added later in front of the (K) symbol. Following that transitional frame I see a majority of BATxxx Attitudes and only a couple more ATxxx Attitudes, implying a switch over to BAT.

Update 02/13/2015
After collecting numbers for another year or so I've found that ATxxx frames continued on (up to AT28d or 653) for a while after AT12E (#302) implying that either the problem wasn't resolved right away, or that the addition of the B to the serial number wasn't correlated with the head tube issue. It's possible that the process changed and the S/N schema was revised later on for another reason. More and more I think that the change had more to do with subtle frame redesign including the cable inlets, top tube length and the head tube fix. That would make more sense to me, but I don't have any confirmation that this is what actually happened.

I believe that ATxxx Attitudes preceded BATxxx Attitudes because all ATxxx Attitudes have the downtube cable inlets located above the centerline, a feature known to be found only on very early bikes. While very few BATxxx Attitudes are found with those same cable inlets.

ATxxx cable inlets - rotated up from centerline

BATxx Cable inlets - on centerline

All of the ATxxx and BATxxx Attitudes I've identified had box forks, solid black decals and the Klein stamped headset seal. So, I think it's safe to say that if your Attitude has an AT or BAT serial number it's a 1990.

Fork serial numbers in 1990 would start with 5A.

In total I believe that Klein made around 2300 Attitudes in 1990, give or take. The highest fork serial number is right in that range so that seems to make sense.

1991 / 1992 Attitude: (REVISION PENDING)

While 1990 was the introductory year full of discoveries and changes, 1991 and later 1992 were both years of mass production and relative consistency of features.

Main features of 1991 Attitudes include:

1. Uniklein fork (altough the catalog still showed the box crown fork)
2. Solid black decals (later switched to black with white outline Attitude logo closer to seat tube)
3. Smooth MC1 headset set

1991 was the year Klein introduced the legendary Uniklein (round crown) fork. Evidently the early box crown forks were somewhat prone to failure and sometime in late 1990 early 1991 Klein switched to the stronger and somewhat less harsh Uniklein fork. I've identified very few 1991 Attitudes with factory installed box crown forks, but they're out there.

I believe that 1991 Attitude frames had a serial number format Axxx and the forks had a format AOxxx. The earliest Axxx Attitude I have recorded is #92 and the highest is #3498, while the highest fork comes in at #3757. The higher number might account for extra forks built to replace broken 5A box crown forks. At some point, either in late 1991 or early 1992 Klein relocated the serial numbers from the rear dropout to underneath the BB shell. This provided more space and allowed them to use a longer string of characters. This led to the new ATxxxxxx format. Out of the 60+ Attitudes I've only spotted two with this format ATT000111 and ATT002433. Although I do not have enough data to prove this it seems that sometime around late 92 Klein switched the fork serial format to Axxxx, with the highest number in my record of #2203.

So, it would seem that Klein built somewhere around 3700 Attitudes in 1991 and perhaps another 2400 in 1992. The fork numbers don't seem to corroborate this, but this is still a fairly limited data set. It's also very likely that the number of rigid forks would be less than the number of frames since 91 and 92 saw wider adoption of suspension forks, hence fewer rigid forks required to outfit frames.

1993 / 1994 Attitudes: (REVISION PENDING)

The 1993 Attitude was the final version of the MC1 Attitude and it was the model year most closely related to the Adroit. Unlike it's predecessors which had a 1 1/4" (27.2mm seatpost) seat tube the 93 Attitude went up to the 1 3/8" seat tube (31.6mm seatpost) used on the Adroit. This reduced the seat tube extension above the seat tube from 6cm to about 2. Also, unlike the earlier Attitudes with a 1 5/8" down tube the 93 Attitude received a larger 1 7/8" downtube, closing in on the massive 2" downtube on the Adroit.

Also Klein stopped using decals in 1993 and started debossing their frames.

1993 also marked the introduction of a new serial number scheme. The fairly non descript ATTxxxx was first replaced with T for Attitude 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 T.

The highest number 1993 Attitude I have recorded was from April of 93 at #1695. The previous number was from February at #1271. So it's safe to say that another 200 or so were made before production switched to MC2 bikes in July 1993.

Although 1993 was the last official production year for the MC1 Attitude the rollout of MC2 bikes was slow and Klein sold a small quantity of MC1 Attitudes in 1994. I have very little data on this but I think it's safe to say that 200 more MC1 Attitudes were built and sold as 94 model year bikes.

So, in total this would bring production of 93/94 MC1 Attitudes to around 2000 give or take.


All in all I estimate between 8,000 - 10,000 MC1 Attitudes were made by Klein between 1990 and 1994.

The data set supporting these conclusion is relatively small compared to the total production numbers, but it is the largest such data set ever compiled. So, although these conclusion are made on limited data they seem plausible.

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.