The Tryphonos, named after designer / builder Mike Tryphonos, is a hub center steering British motorcycle that first appeared in his engineering dissertation in 1990 and gradually evolved as he produced a series of prototypes building on the lessons learned at each stage. Mike looked at motorcycles and found, as many had before, that the fork has several problems when operated under conditions of high speeds and twisty roads. Flex, stiction and the mass of the fork itself, create problems especially when you run steep steering angles like those found in racing motorcycles and high performance street bikes. Hub center steering gets around those issues by isolating the front suspension so it can do its work while the wheel is busy with other things like steering.
The Tryphonos has evolved from the initial 615cc prototype to the current ZX-10R powered version. It has been raced at the Isle of Man and everyone that rides it, including several magazine testers, likes it a lot. He would like to build a road version and perhaps, if the right investor can be found, he'll be able to do it.
Hub center steering uses a front swingarm which seems to look just enough out of the ordinary that any motorcycle using it has to get past quizzical looks, some like the look, some not so much. Bimota, Yamaha and Vyrus, among others, have previously built or are presently building hub center steering designs which may work great but you don't see many of them on production motorcycles. Of course, high price may play a part but if it works so well, why haven't more manufacturers tried it and given the higher production numbers a chance to bring down the cost? Does it work well enough or is it sufficiently superior to conventional forks that there is a real reason to use it instead?
Hub center steering can be heavier, depending on design and steering lock can be limited compared to a fork, again, depending on design. Without a steering head, however, it can lower frontal area if streamlining is a concern, good for racing but not so important on the street.
Hub center steering is an interesting design that keeps popping up but never really takes hold. Other than the companies mentioned above, no one is really doing anything with it except for a few custom builders like Ludovic Lazareth on his V-Max powered custom, which seems very well done, and at least one other custom that comes to mind not done as well, where hub center steering is more curiosity than engineering.
I wish Mike Tryphonos all the best, we'll have to see if he can take his idea further than any of others have.
Thanks for the tip, Andy!