Patent Round-up: Shimano's Crazy Derailleur, Electronic Shifter & SRAM's Floating Brakes

Digging through patent documents can sometimes offer hints at what we might be riding in a few years' time. Often the wacky designs don't see the light of day, but even then, it's interesting to see what ideas the bike industry's brains are working on. Here are a few that we've spotted lately.

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Shimano's three jockey wheel derailleur

We first spotted this one on Cycling News. It's a patent from Shimano for a derailleur with three jockey wheels, apparently designed to offer more ground clearance with a wide-range cassette. There is an upper jockey wheel in about the normal place that guides the chain onto the cassette, but instead of one lower wheel to tension the chain, it has two. These wheels are positioned horizontally in front of the first one, keeping them higher off the ground. The chain wraps around the two tensioning wheels, which are mounted on opposite ends of a spring-loaded arm that pivots between the two. When the chain shifts into a larger sprocket, the arm rotates such that there's a shorter path for the chain to go from the chain ring to the upper jockey wheel.


The key advantage is that it stays higher above the ground than a conventional derailleur cage. The patent also states that it can be used with a cassette with a wide gear range. Perhaps that means a wider range than Shimano's current 10-51 tooth cassettes is on the cards.

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SRAM's three-piston floating brake

A patent from SRAM shows a single-sided, three-piston disc brake. While most mountain bike brakes use an opposed-piston design, with either two or four positions arranged in pairs, sIngle-sided brake calipers are typically only seen on budget bikes. Usually, they have a single piston that pushes a moveable brake pad against the rotor, which bends it towards a fixed brake pad on the other side.


In this patent, the rotor is separated into two parts - the carrier and the brake track. The carrier is thick and is fixed to the hub; the brake track (the part which the brake pads rub against) is connected to the track in such a way that it can slide, or float, axially (side-to-side) on the carrier. The patent depicts many ways in which this could be achieved.


The drawings show a caliper with three pistons on the inboard side, pushing a moveable brake pad towards a fixed outboard brake pad. When the brake is applied, the brake track will slide toward the fixed pad.


The caliper mounts to the bike in a different way from the post-mount standard we've been using for years. The caliper connects to the frame with a loop that's concentric to the axle, and there's a lateral stub on the frame with a bolt fixing the caliper body to the frame or fork. Although a drawing shows it being connected to a post-mount fork, it looks like this design would require a new frame mounting standard.

What's the advantage? The patent mentions that conventional brake calipers require careful alignment to avoid brake rub and poor braking performance. Plus, as the pads wear and the pistons advance to compensate, they rarely advance evenly, leading to uneven pad wear, brake rub and poor brake performance. The patent claims that the "self-centering or floating rotors address at least the drawbacks noted above."

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Shimano electronic shifter?

Finally, Shimano has a patent for an electronic controller that's shown connecting to a brake lever. The patent doesn't say what it's for (patents are always as open-ended as possible) but its position under the right-hand brake lever in the main image and the fact it has two buttons make it a pretty good guess that it could be used as a shifter. Having said that, one advantage of electronic components is that they can be configured to do multiple jobs, so perhaps the same device (or a left-hand version) could be used to control an e-bike motor, dropper post, suspension settings, or more.


The patent says that it could include a "wireless communicator." This would be a new direction from Shimano as their Di2 electronic shifting has always communicated with wires. Will we see a wireless electronic derailleur from Shimano? I wouldn't hold my breath, but a wireless controller/shifter with a derailleur powered by a battery in the frame could be a good compromise, especially for e-bikes.

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