SunTour's Achilles Heel

We all have heard of the "Achilles heel":  a weakness that causes the downfall of an otherwise strong person or thing.

We have all heard--probably from a junior high school teacher--the origin of the phrase:  After giving birth to Achilles, his mother Thetis tried to make him immortal by dipping him into the River Styx.  As she dipped him, she held him by his heel--which, of course, remained untouched by the magical waters.

Until I read the Iliad for myself, I--like most people--assumed the original myth about Achilles said that his weak spot was his heel.  However, the Iliad identifies his weakness as his pride; the first story to say that his weakness was in a part of his body was Ovid's Metamorphoses, published more than a millenium after the Iliad.  Roughly half a century after that,the Roman poet Statius was the first to imply that it was his heel.

Practitioners of traditional medicine all over the world have said that pride, as well as other emotions such as anger, manifest themselves in the body.  Perhaps, then, it's not a stretch to say that organizational pride or overreach can become the "Achilles heels", if you will, in the products they make. 

SunTour VGT-Luxe rear derailleur,  circa 1973

Such was the case with a bicycle part from a company that had enjoyed enormous success for two decades.  From the time SunTour introduced the slant-parallelogram rear derailleur in 1964, it took both the original-equipment and replacement-parts market by storm; by the end of the 1970s, the traditional European derailleur manufacturers commanded only small niches of the bicycle market.

But there were clouds on the horizon for SunTour.  For one, its patent on the slant parallelogram would expire in 1984.  Other derailleur manufacturers were waiting with bated breath; practically the minute the patent expired, Shimano would incorporate SunTour's design into its SIS derailleurs. Campagnolo would follow suit when it developed its first intergrated indexed shifting system.  

Huret Duopar rear derailleur, circa 1981

Another sign of trouble preceded the end of its slant-parallelogram patent:  Huret's introduction of the Duopar rear derailleur.  Frank Berto, who had so lavishly (though not unjustly) praised SunTour derailleurs for the better part of a decade, pronounced the Duopar as the best wide-range touring derailleur available.  The majority of SunTour's market in the 1970s and early 1980s was bicycle tourists and other cyclists who wanted and needed wide-range gearing.  The Duopar represented the first viable threat to SunTour since its first GT derailleurs were introduced during the late 1960s.

There was, at least, a silver lining in the Duopar cloud:  Huret's new wide-range touring derailleur indeed shifted flawlessly over the widest gearing available at the time--at least, when it was new.  But its double-parallelogram (hence the name Duopar) design necessitated more robust materials and construction than Huret offered.  So, it would rather quickly develop play and slop in the joints, especially if it was ridden in rain and mud, and would typically last about 2500-3000 kilometers.  

SunTour wanted to re-establish itself as the go-to derailleur company for dedicated bicycle tourists.  While the Duopar shifted better--when new--than any other wide-range derailleur, it wasn't that much better.  Apparently, the designers at SunTour figured they could develop a derailleur that would out-shift and out-last--and, by the way, look more elegant than--the Duopar.

The folks at SunTour, I imagine, also must have been thinking that such a derailleur would take the then-nascent world of mountain biking by storm:  the Duopar was simply too fragile, and the derailleurs Shimano made at that time didn't shift nearly as well.

SunTour Superbe Tech, 1983

So, in 1983 SunTour came out with the Superbe Tech rear derailleur.  Like the Duopar, it had a double pivoting system.  The difference was that, instead of a second set of pivoting  parallelograms attached to the main one (as the Duopar had), the Superbe Tech featured a spring inside the upper pulley wheel.  That meant, of course, that the pulley wheel had a much larger "drum" than the upper pulley of any other derailleur and was therefore not interchangeable even with the pulleys of other SunTour derailleurs.  

But its sizing isn't the only thing that made it an "Achilles heel."  The spring was not adequately protected from dirt, mud, rain or anything else one might encounter. So the spring and pulley drum would become clogged, which in (relatively short) time would cause the pulley wheel to seize, and the spring to fail.  Even the most dedicated shop mechanics couldn't fix it--or the fully-enclosed main parallelogram, which had even more complicated internals. 

The spring-loaded pulley wheel helped to make the Superbe Tech the best-shifting derailleur available--when it was new.  But, after some use, the pulley wheel  would seize up and turn the derailleur into a paperweight.  

In trying to defend itself against an onslaught from its competitors, SunTour created a derailleur with a sophisticated design and elegant appearance that indeed shifted better (in part, because it eliminated the need for cable housing) than any other derailleur--when it was new. However, just as Thetis didn't think to dip her son a second time to ensure that his heel would be soaked with Stygian water, the folks at SunTour apparently didn't go back and correct the weakness inherent in their new design.  So, in trying to protect themselves from the threats imposed by Huret and, later, Shimano, they made themselves vulnerable in a seemingly-small area.  

While the Superbe Tech's flawed pulley wheel did not, by itself, cause the demise of SunTour, many in the world of cycling believe it was where SunTour suffered its first debilitating wound.