SunTour’s first parallelogram derailleur, the 1963 SunTour Skitter, is widely considered to be the work of someone other than SunTour (possibly Huret).
But for 1965 SunTour produced their very own, fiendishly clever, design - this beauty - the SunTour New Skitter. It was also largely constructed of riveted flat steel plates, but the New Skitter incorporated a shed load of innovations. It had a slant parallelogram, it had the adjustment screws clearly labeled and positioned at the rear and it had a highly three dimensional cast bronze rear knuckle.
It also had the two trademark features of SunTour’s own Skitter designs - it is low-normal (what Shimano now call ‘rapid-rise’) and it had only one spring, which, through devious design, provides both chain tension and operates the parallelogram.
SunTour had a long obsession with the idea that both gear levers (for the front and the rear derailleur) should operate ‘the same way’ - i.e. you should either push both levers forward for lower gears or you should push both levers forward for high gears. At the time (and for several decades afterwards) the convention was to push the right hand lever forward for high gears at the rear derailleur, but to pull the left hand lever back for high gears at the front derailleur. The low-normal design of the Skitter was an attempt to solve this problem.
However, I have never been a particular fan of low-normal systems, as, if you do not keep them clean and lubricated, the spring looses the ability to do the ‘hard work’ of moving the chain onto larger cogs - yet another technology that is good for careful (tanned Californian) users in a dry (tanned Californian) climate, terrible for sloppy (pasty-faced British) folk commuting through mud-laden (pasty-faced British) drizzle.
A few years later SunTour took another run at this problem with the Spirt front derailleur, which also worked ‘backwards’ (in this case being a front derailleur that was top-normal). This suffered from the same problem - the ‘hard work’ of moving the chain onto the larger cogs eventually defeated the spring.
A proud member of the pantheon of derailleurs with silly names.
Browse associated documents.