vintage trailing axle

[dingleberry]

While thumbing through an old bike magazine I came across a photo of a Beasley framed Velocette c1958. The interesting thing is the front trailing axle just like the Vision. Found a pic online, bit small but you can see ok. http://www.mkviiiktt.co.uk/Specials/SpecialsP1.html
Anyone know much about the history of this set up? This is the first I've seen other than the Vision. 

[Rikugun]

In the 4th paragraph it reads "It appears to have the typical duplex frame and the 'trademark' reversed Velocette front forks."

Could that mean the builder was using the 350 racer's leading axle forks but reversed to obtain a particular handling quality?

[skucera]

In the 4th paragraph it reads "It appears to have the typical duplex frame and the 'trademark' reversed Velocette front forks."

Could that mean the builder was using the 350 racer's leading axle forks but reversed to obtain a particular handling quality?

I think you're on to something.  Simply pulling in the trail by reversing the dampers would make for much less self-centering, and make the steering much more "responsive" at the expense of stability.  It would also require keeping the rider's hands on the handlebars at all times, just like riding our Visions.

Conversely, I wonder if reversing our dampers to add trail would make for "hands off" stability like a Harley?  Personally, I like the agile handling of this motorcycle, but the guy I bought my Vision from bought a Harley and really likes the way it cruises.  He thought the Vision was too "nervous."

Scott

[dingleberry]

How did I miss that about the reversed forks I wonder? Anyway my point was that this was an idea that was used many moons before Yamaha produced it on their bike. Although perhaps not by many and only modified racers?

[Rikugun]

Conversely, I wonder if reversing our dampers to add trail would make for "hands off" stability like a Harley?  Personally, I like the agile handling of this motorcycle, but the guy I bought my Vision from bought a Harley and really likes the way it cruises.  He thought the Vision was too "nervous."

Scott

You mean like this?   I was fooling around with my parts bike to test feasibility a few years back.

Dingleberry - I appreciate your point. Until you posted this I wasn't aware of any other trailing axle applications. Thanks for posting the link.

[QBS]

The Harley riders "nervous" V might have been suffering from a bad case of worthless stock steering head bearings.

[Rikugun]

I completely forgot about another Yamaha with trailing axle design. It was compact and hard to keep the front wheel on the ground relative to comparable models (4 stroke, ~200cc displacement) of the day. At the time I attributed some of this to the front axle placement.

http://imganuncios.mitula.net/1985_yamaha_225dx_99607591272887038.jpg

[George R. Young]

Steering response is governed by the steering stem axis and the axle location. If you fix those two, you can put the forks wherever you like by designing the fork sliders and triple clamps. I thought the main benefit of the Vision's trailing axle forks was that it moved the fork tubes ahead and thus allowed for a bigger gas tank.

[skucera]

The Harley riders "nervous" V might have been suffering from a bad case of worthless stock steering head bearings.

No, I've been riding the bike for months now, and I think he was just wanting a less lively steering feel.  The head bearings are fine.  Some nervousness was from a worn, squared off rear tire, and that nervousness went away with a new rear tire.  However, I definitely can't pull my hands off the bars even for a moment when riding, or the bike goes into progressive steering oscillation, with some weaving built in... not a reassuring sensation.  With my hands on the bars, the bike runs straight and true, especially after I bolted on the fork brace that my previous owner had in a box of forgotten extra parts that he brought to me about a month after I bought the bike from him.

Scott

[fret not]

Forks will encounter the radiator shroud before they touch the tank.  I tried putting a set of '89 FZR 1000 forks on mine but they hit the radiator because there is much less set back between the fork tubes and the steering stem.  I have noticed that most recent bikes have the fork tubes and steering stem nearly in a line compared to the older street bikes.