Shimano patents three-pulley rear derailleur that could revolutionize things

The Japanese brand continues to record ideas that could indicate where the future of bike shifting may be heading. Shimano's latest eye-catching idea is a total redesign of the shifter pulley operation that would eliminate the need to use the usual clutch systems that prevent the chain from rattling when pedaling over bumpy terrain on our gravel or mountain bike.

Three better than two

The registrations that bike and component brands make at patent offices often serve to try to guess what their respective development departments are working on when coming up with new products.

In most cases, these patents are not specific products as such, but contain concepts that are registered to prevent them from being exploited by competitors, even if they are not ultimately used in any product. Other times, these ideas manage to reach an early prototype stage, although the reality is that the idea was not as good as it seemed and is abandoned.

Finally, some of these concepts, which years before were reflected in the corresponding patent, end up being part of products that actually reach development and, in some cases, represent a small revolution in the operation of some components that we considered unalterable.

The latest eye-catching patent that has attracted significant attention in the cycling world is from Shimano. It is a complete redesign of the derailleur pulley box, which would have three pivot points, actually 4, with an arm that comes out of the body of the derailleur in the position that the pulley box would occupy in a conventional derailleur. At its end, the novelty, the pulleys themselves would be placed, with a box that is anchored in the middle part in a second pivot point.

In this way, a kind of rocker arm is created with the pulleys located at both ends of this new piece. There are two objectives of this concept. On the one hand, to reduce the size of the pulley box, an element that has been increasing in size due to the need to increase the capacity of mountain and gravel derailleurs in the face of the use of cassettes with increasingly larger ranges and gigantic crowns such as the 10-51 cassettes of the XTR groupset.

Moreover, this arrangement would make it possible to dispense with the clutch systems used in today's gearboxes to prevent the chain from swinging and keep it firmly in place.

The idea of including three pulleys in the rear derailleur is not entirely new and has already been explored in the past by Suntour, when this brand produced reputable groupsets for those early mountain bikes of the late 1980s, although with a completely different concept than the one now proposed by Shimano's patent.

Time will tell if this curious rocker becomes a common sight on our bikes or, like many other ideas, is shelved. In fact, in recent decades the changes in bike mechanics have been very subtle. It is rare to see a major revolution, mainly because of the risk involved in trying to introduce such a product to the market. Even the introduction of electronic groupsets at the time was done very cautiously and, despite building on the existing mechanical base, it took a long time to become a common sight on our bikes.

Shimano did not do so well with other ideas developed in the past. Their Biopace oval chainrings come to mind, which supposedly favored pedaling although their design placed the maximum ovality in the dead center of the pedal stroke achieving the opposite effect, or those Shimano Airlines derailleurs designed for downhill bikes that were operated by compressed air contained in a reservoir located in the usual position of the bottle cage.