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What Is A Hub-center Steering Motorcycle and Why Aren’t There More of Them?
Hub-center steering is one of several different types of front-end suspension and steering mechanisms used in motorcycles and cargo bicycles. It is essentially a mechanism that uses steering pivot points inside the wheel hub rather than a geometry that places the wheel in a headstock like the traditional motorcycle layout.

What Is A Hub-center Steering Motorcycle and Why Aren’t There More of Them?

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Perhaps the most venerable example of the idea came in the form of the 1930 Majestic. This George Roy design used a novel pressed-steel monocoque chassis, and it incorporated an automotive-type chassis with hub-center steering. Other bikes had already used the configuration in such machines as the Ner-A-Car and the Zenith Auto-Bi, but the Majestic made it lovely to behold.

Another bike, the Vyrus 984 C3 2V Razzetto, was one such motorcycle that used hub-center geometry.

Vyrus is a small Italian motorcycle manufacturer based in Coriano, Italy, and their bikes such as the "Tesi" - Thesis in Italian - had their designs originate from a university engineering project linked to the motorcycle legend Massimo Tamburini. The Tesi, and the Vyrus 984, were instantly identifiable by their use of their hub-center steering front suspension and steering arrangement.

Those fabulously expensive bespoke motorcycles have been called “functional works of art,” and they look a bit like something you might see in a video game.

In hub-centered bikes, the front wheel is attached to a swingarm with a shock and an internal pivot point. Steering is achieved using those linkages to turn the wheel on a pivot point. Hub-center steering has been employed on motorcycles for more than a century, but the design, despite what some engineers say offers a distinct advantage, never took hold.

But the founder of Vyrus, Ascanio Rodorigo, once worked for Bimota as a race mechanic and engineer during the 1970s and his tenure there lasted until 1985. When Rodorigo finally left Bimota, he started his own company but partnered with Bimota on the hub-center-steered Tesi. He then went on to take the steering concept deeper and refined it for his own company’s motorcycles.

A Ducati dual spark bored out to 1,079cc and making 100hp L-twin provides the power for the 319 lbs (145 kg) Vyrus 984 bike, and it's delivered to the road for via a six-speed transmission.

Now builders like Bryan Fuller of Fuller Moto, Revival Cycles, and others have built beautiful machines which harken back to the hub-centered glory days of the Majestic. Builders such as Stellan Egeland used a hopped-up 1200 boxer engine from a BMW HP2 Sport. He also added his own hub-center steering setup from ISR to a frame he made from a 2391 steel tube. The ISR kit is a thing to behold.

Revival’s ‘The Six,’ which features a ballsy Honda CBX motor, is another take on the hub-steer geometry. It was commissioned by museum owner and bike collector Bobby Haas for his Haas Moto Museum in Dallas by Revival's Alan Stulberg and his crew.

Stulberg said the commission was aimed at paying homage to the Art Deco classic Majestic and added that he and the team became "obsessed with its design language and flow" since they first saw the bike at the Barber Museum.

So why don't more motorcycles feature hub steering systems? They don't dive as much under braking and hard cornering as do conventional telescopic fork setups. They push braking forces back into the chassis more efficiently rather than transferring immense bending forces to a pair of upright forks. The ride experience is exceptional as braking performance throughout corners is greatly enhanced.

It works like this: A wheel hub pitches back and forth on a central pivot and is supported by two large steering arms actuated by handlebars. The handlebars connect to the front steering and swingarm using complex linkages. A fixed arm connects a pull-and-push rod on either side of the hub-center to help steer the bike. The geometry also includes a second pair of static rods to ensure the axle stays level with the bike's mass.

While hub steering has a number of clear advantages, its downfall is that it is considerably more expensive to manufacture and maintain and requires exceptionally experienced mechanics to tune and repair.

But it does look good, works more efficiently from an engineering standpoint, and directly addresses the most important factor in the motorcycling experience: braking.

 
 
 
 
 

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