Shimano Airlines, or pneumatic derailleurs

Hmm, how do you control a derailleur? Early shifting systems used a pushrod, and even before that, you had to stop and move the wheel in the dropouts to adjust the chain tension to the size of the sprocket. Soon after, steel cables and counteracting springs were employed – a solution that remains in the vast majority of bicycles today. It works well, but it's not without its flaws. Cables and housings wear, rust, and are susceptible to dirt. Hence, alternative gear shifting methods have appeared from time to time throughout cycling history. One example is the quite successful Shimano Positron system from the 1970s. It used a special, stiff cable (compared by the manufacturer to a piano wire) that both pushed and pulled the carrier, eliminating the need for a spring. I worked with it; the setup was incredibly simple, the operation a bit clunky, but effective.

Of course, the most popular alternative is electric. It's temperature-resistant, dirt-resistant, and, in the case of wireless systems, easier to install. Furthermore, it offers the ability to place shift buttons in multiple locations and personalize their operation. And this isn't a completely new idea. Contrary to popular belief , electric derailleurs were available as early as 1993 ! Today, however, I'll talk about something much more interesting: the Shimano Airlines groupset, controlled by compressed air.

What is Shimano Airlines?

This groupset, introduced in 2000, was designed for downhill riding. Interestingly, it was only available in a 1x7 configuration. It consisted of a rear derailleur, cassette, two shifters, hoses, a central pressure distributor, and two compressed air tanks. Quite an unusual setup, eh?

Shimano Airlines was unusual in every way

Let's start with the name. It's awesome and so different from the boring Shimano nomenclature that it's hard to believe it even made it through corporate throats choked with Japanese ties. The design of the kit is similar. These are probably the only Shimano components that evoke the crazy CNC era and the iconic Paul brand. Sharp lines and the brand logo wrapped around the derailleur—never before or since. I love it—if I ever manage to build a Shimano Airlines bike, I'll have to style myself a Danzel. If they could, these parts would wear sunglasses, a bleached-gel haircut, and a black flame-patterned shirt.

More importantly, however, is that it's a solid, well-thought-out piece of equipment. For example, the aluminum seven-speed cassette—the four largest sprockets sit on a special bracket with a spacer that protects the spokes in the event of a chain drop. This solution is currently used by companies like SRAM. The distance between the levers and the handlebars can be adjusted to your preference. The pressure distributor is equipped with miniature pressure gauges and a valve, allowing you to fill the bottle with a standard pump. The latter can be attached instead of a bottle cage. Its capacity was sufficient for approximately 400 gear shifts (I also found some reports mentioning 200 and 600 shifts).

How did it work and why exactly?

Quite simply. One shifter controlled upshifts, the other downshifts, opening a valve that directed air from the tank to the derailleur mechanism. This simplified control was Shimano Airlines' main goal and advantage. Back then, downhill riding was a rather suicidal pastime, so the ability to change gears with just a casual flick of the lever made a lot of sense, especially considering the smooth operation of the shifters of the time. An additional advantage was the quick action and (according to some sources) the greater flexibility of the pneumatic hoses compared to traditional housings. This was intended to aid in the installation of components in the crazy and complex full-size frames of the turn of the century. The latter doesn't quite convince me, but maybe? The fact is, this is the wildest era of cycling.

Users agree that the whole thing worked... great. This is likely due to the extensive testing Shimano conducted several years before the product's official launch. So why don't we pump up our air tanks before riding these days?

Disadvantages of Shimano Airlines

Pneumatic derailleurs didn't take the market by storm for two reasons. The first was a single, significant technical flaw: sensitivity to the surrounding air. They didn't work very well in low temperatures. And in the cold, they didn't work at all. Perhaps that would have been resolved, but worse still, they weren't as efficient at high altitudes. And that, you'll agree, is a problem with downhill gear. And that's probably why the issue wasn't pursued. Secondly, the Shimano Airlines groupset was incredibly expensive – it cost $1,600. Taking inflation into account, that's roughly the equivalent of $2,550 today for seven speeds. It's no wonder, then, that many stores are left with the product, which now fetches even more absurd prices as a collector's item and a speculative item. For example , here you can buy an unused set in its original box for (a trifle) almost 5,000 euros. Any takers?

Photos are from the official Shimano website