I've written before about one of my favorite SunTour derailleurs - the Vx, which was an attractive and durable workhorse for a bargain price. Today I want to take a look at another favorite, the slightly more upscale Cyclone.
One of my first nice bikes, a Schwinn Super Le Tour, was equipped with a Cyclone, and it made a good impression on me. One of my favorite vintage bikes currently uses one, and I have several more examples waiting for the right projects to come along.
When the Cyclone first came out, around 1975, it was a revelation: beautifully finished, shockingly light (about 175g), and functionally flawless. One of the unique things about its design was the "hidden" cable routing which went straight through the parallelogram. It looked cool, and made for a very direct path for the pulling forces that would actuate the unit - which I would expect would somewhat reduce the torque that the parallelogram pivots are normally subject to. The downside was that it made cable replacement a little more complicated. I've found in my experience that there is no re-using old cables, because any little kinks in a used cable make it almost impossible to feed through to the body to the fastening bolt. As long as you have a nice, new, unmolested cable, it is actually easier than it looks.
The Cyclone also came in a long-cage touring version, the Cyclone GT. This would have been one of the lightest touring derailleurs available. Yes, the Huret Jubilee was also available in a long-cage touring version, and was lighter than the Cyclone, but the Cyclone would have shifted better over a wider range, while costing significantly less.
Around 1981, the Cyclone got a complete redesign, which reflected the trend towards aerodynamics. The Cyclone M-II was attractive, and beautifully finished, but also a little bit "generic." Gone were the embossed logo and other visual interest points. Everything was smoothed over and sculpted. Logos (while minimal) were screen printed on. No doubt this was a response to the introduction of Shimano's Dura Ace AX aerodynamic group, but unlike Shimano, SunTour didn't spend buckets of cash marketing the supposed aerodynamic benefits (which were questionable anyhow). Shimano's aero groups never really caught on, and were quietly dropped after a couple of years - but the smoothed out, almost featureless aero look stuck around for the rest of the decade. One thing about the M-II generation is that it was even lighter than the original. Many sources put the weight somewhere around 165 grams!
The next (and final) generation of the Cyclone would be the indexing-compatible "accushift" version, which was a very nice derailleur - and a little more svelte than the 3rd generation, but I don't have an example in my collection. Accushift never worked as well as Shimano's SIS, and it was only a matter of time before SunTour would end up buried. Such a shame, really.
Of the three Cyclones I have shown here that aren't currently attached to any bike, one of them will be installed on a bike soon - but I have to decide which one to use. I'll have to keep you posted.
That's all for now. . .