Honda’s Hossack Forks On a Superbike?

Will Honda use an alternative fork design in MotoGP?

Honda Hossack Forks
Is Honda patenting a new type of front end for it’s MotoGP team? Merging the patent drawing with a photo of Big Red’s RC213V-S machine makes it seem like a plausible fit.©Motorcyclist

While a patent is never a cast-iron guarantee that a project will see the light of day they're an intriguing peephole into the inner workings of the most secretive R&D departments. And the latest from Honda is particularly eye-opening. It describes, and illustrates, a design for a Hossack-style front suspension system specifically created for high performance and race applications. The pictures show the setup fitted to the instantly-recognisable frame of an RC213V MotoGP machine, or possibly its RC213V-S road-going spin-off. The engine outline, while lacking its cylinders, also resembles the firm's current V-4 race unit.

Hossack forks, named after British engineer Norman Hossack who pioneered their development in the 1970s, are a well-established system. BMW’s Duolever front end, as used on the K1300 and K1600 models, illustrates their use in mass production, while the likes of John Britten’s legendary V1000 showed that they could also be of use on the track. Not to mention Hossack’s own racing exploits on a variety of machines modified to use his suspension design.

Honda Hossack fork blueprint
Honda’s take on a Hossack fork: Note that the steering tube is mounted behind the front pivot points of the wishbones, making the system more compact.©Motorcyclist

Honda's patent revolves around tweaks to the design rather than a wholesale rethinking of Hossack's idea. Just like other Hossack-suspended bikes, it uses an upper and lower front wishbone extending from the frame and attaching to a tube that acts as a pivot for the fork, which are simply a cast or fabricated aluminium part, shaped like an inverted 'Y' to hold the front wheel and brakes. At the top, a simple two-part linkage translates movements of the bars to the fork while allowing the suspension to rise and fall, while a single shock is bolted to the lower wishbone and the bike's frame to provide both springing and damping.

The element of the newly-patented Honda design that appears different is the way the main steering tube is mounted behind the front pivot points of the wishbones. That allows the wishbones themselves to be longer without adding to the overall length of the bike. But why bother with an alternative front suspension system when telescopic forks are already so capable and well-developed? In racing in particular, the answer could be that a Hossack-style front end might allow the leap forward that every team is always striving to achieve.

Hossack fork benefits
There’s no question that this system is more complicated than a typical telescopic fork, but the reward could be worth it on every machine from a MotoGP racer to a sport-touring bike.©Motorcyclist

Telescopic forks are arguably a triumph of development over design, since they have intrinsic problems that are impossible to overcome. Our own James Parker will surely testify to that. They are subject to flex—both longitudinally and laterally. They need to be hugely thick to cope with massive braking forces, but when banked in a corner there are schools of thought that suggest an element of lateral flex becomes useful to soak up bumps. Hossack suspension allows longitudinal and lateral rigidity to be tuned differently – since they're not round in section, they can be made to flex sideways but not in the front-rear direction.

The wishbone arrangement also means there’s a mass of additional geometry options available, altering or eliminating dive under braking if necessary, and the wheelbase no longer needs to get shorter as the front end compresses. This could be particularly useful in racing, potentially allowing harder braking before the back end lifts.

Centralizing mass of the Hossack fork system
Centralizing mass could be a benefit of this system—with the shock tucked up near the front of the frame—but the main benefit on a performance bike would likely be anti-dive during braking and being able to more finely tune lateral flex.©Motorcyclist

Another part of the Honda design that the patent focusses on is the positioning of the bars and the compact design they use. The patent says: “Especially in race vehicles, there are strong demands for lowering the height of the handlebar while making the layout of the handlebar more compact, and therefore the benefits are greater.”

Interestingly, Honda is expected to be taking on a Hossack-style front end for the next-generation Gold Wing, which is well under development already. While it couldn't be further removed from the RC213V in its performance and intentions, the Wing's massive weight and size mean it's also in a position to benefit from the system's longitudinal rigidity and the greater scope for imaginative geometry. Also, by using a Hossack system on both its range-topping, technology-focussed next-gen Goldwing and on a future MotoGP machine, Honda could bring instant customer acceptance to the alternative front end, allowing it to be adopted across a much wider array of production models.

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Zack Courts Rides Honda's $184,000 RC213V-S!©Motorcyclist

Will this design actually see the light of day? In terms of racing, it will surely depend purely on performance. No doubt there will be behind-closed-doors tests to see whether the design's on-paper benefits will allow it to overcome the decades of fine-tuning that have already gone into telescopic fork design. If they do, then we could be looking at the next big thing in racing, and as a result surely road bike design. If they don't, then these drawings may well be all we ever see of the idea.