After Pete suggested the "MX" suffix used on the UK/Euro monoshock models stood for "monocross", I decided to investigate that possibility.

There is no debate from me on the point that the "monocross" Enduro models were revolutionary, successful, and important landmarks achieved by Yamaha.  I'm simply interested in the potential original "marketing"meaning of the "MX" suffix that appears to have only been used by the UK/Europe Yamaha Importer based in Holland...  i.e. DT175MX

Was the "MX" suffix a marketing strategy originally intended to highlight the revolutionary "monocross" suspension? 

It's important to note that my research found that in other areas of the world...  sales markets where the "MX" suffix was NOT used...  Yamaha used the "monocross" term liberally in their advertising and brochures.  This makes it important to look carefully for early monoshock examples with the "MX" suffix...  advertising, articles, and brochures that do not contain the "MX" suffix are very likely not from the UK/Euro market.

The Case Against "MX suffix = monocross"
Our own Tech Library here has early/introductory Yamaha Holland (UK/Euro distributor) brochures for the DT175MX, DT250MX, and DT400MX.   I did not find the term "monocross" used even once in any of them!  The rear suspension design is referred to as "Monoshock suspension system de Carbon".
I just don't find it likely that Yamaha Holland is going to add an "MX" suffix to the model name of the monoshock models they are selling in the UK/Europe to specifically highlight the "monocross" design and never even mention the word "monocross" in the brochures...  even in places they could have easily used the term...  It would have been very easy to say things like "monocross frame" but they chose to say "monoshock frame".

The Case for "MX suffix = motocross racing DNA/performance"
The DT175MX brochure mentions its similarities to "moto cross" repeatedly...  Even mentioning Mikkola's World MX Championship... This leads me to believe the original intent of the "MX" suffix was to make a connection between the Yamaha monoshock DT models and the World-Class Yamaha motocross models...  the classic "race on Sunday, sell on Monday" marketing approach.

I also found this "motocross racing DNA" theme in magazine articles written in the UK/Euro on the newly introduced Enduro "MX" monoshock models.  I only found the word "monocross" once in a French article spec section on the DT250MX.

Below is the relevant text from the DT175MX brochures...  you as the reader can decide the initial "MX" marketing meaning/target of Yamaha Holland...  were they highlighting the "monocross" suspension design?  or the "motocross" DNA present in their new "MX-suffix" models?
(There is no "wrong" answer...  for all we know the "MX" could have meant the new models were a tribute to "Mademoiselle Xena" ...Ha!)
yamaha-enduros.com/index.php/dealer-broc...5mx-holland-brochure







 

Just an observation, but sometimes the Yamaha advertising/marketing department didn't always consult the technical department!  A classic case over here was marketing literature for the 1977 RD250 and RD400 (so the D model) as being marketed as the RD250/400DX.

On other models over here, DX related to the fitment of a front disc brake.

I think this Yamaha Holland DT250MX 1977 brochure from the Tech Library gives a better understanding of why I believe the '77 onward DT MX series are named as such because of the Monocross single suspension system.
www.yamaha-enduros.com/index.php/dealer-...0mx-holland-brochure
This main theme of this advertisment is to push the "Revolution" of Monoshock suspension over "Double" or twin shock suspension.
It does mention "moto-cross" once when referring to the front mudguard.
In the link shared by PABDT (which I also shared in my first post) there is a video (bottom of the page) from 1973 in Japanese where they coin the term Monocross, and Mark has found reference from 1974 where Monocross is describing Yamaha's mono suspension system.
The answer may lie with the diminutive DT50, in the UK the DT50M was twin shock up until 1980, in 1981 it received an update to Monocross suspension and was also rebadged as the DT50MX.
All food for thought.
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It's a shame the head of Yamaha's European marketing at the time, Makoto Xiao, is no longer with us, I bet he'd know 

Pete,

I completely agree that later on... maybe as early as 1979...  Yamaha UK/Europe jumped on the "monocross" term bandwagon. 

I just find it hard to accept they decided on "MX" as shorthand for "Mono-X(cross) for the intro of the 1977 DT250MX and DT400MX and didn't use the term "monocross" at all in their earliest advertising.  That would be very poor marketing. 

Ironically, other markets like the USA and Oceania, used the term "monocross" quite liberally in their early DT monoshock model advertising...  but they did not add the "MX" suffix to their model names in those markets!

(There is also good reason the later release of 1978 DT175MX had a much harder "motocross" push than the 250/400 released for the 1977...  Mikkola won the World Championship after the release of the 250/400 monoshock but before the release of the 125/175 monoshock.)

There are many possibilities....  Lucien Tilkens invented and prototyped the monoshock system and sold it to Yamaha.  So maybe there were "politics" or even "legalities" involved in UK/Europe that drove the decision to drop the "monocross" term from the advertising at the last minute? 
Heck, maybe even Yamaha themselves told the Yamaha UK/Europe importer (I'm not certain the importer was owned by Yamaha at the time) that they would need to pay an exorbitant licensing fee to use the "monocross" term so at the last minute the importer switched to "monoshock" instead of "monocross" in their advertising?  (But left the "MX" (for "monoshock") suffix on the model names as a subtle "up yours" message?)

We may never know...  I'm still seeing that there was a definite push to connect the DT monoshock introduction to the YZ motocrosser in the UK/Europe during the initial release...  I will see if I can find a copy of one of the 250/400 magazine articles from Europe/UK I read years ago that had that theme.

Thanks for the debate Pete...  we might never know the truth but sometimes the search for it can be fun. 

 

Likewise Mark, thanks for debating the other side.
I have found reference to "Monocross suspension" being abbreviated to "MXS" in an English/French Owners manual.

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So, apparently the mono-cross system was a desired suspension that helped sell bikes.
Note, the seller in this ad wanted an "Enduro". I recall back in 74/75 when I got mine also referring to it as a 125 Enduro, not a DT 125.

These 3 classifieds are from same day, Oct 1976. On the same day,  a YZ400 Monocross was listed!