+
As you can see above, the centerlines between the control arm pivot to the
ball joint are nearly parallel to the line drawn between the drag arm's heim joints.
With a little shimming and adjusting, I can get the drag arm parallel, or at least as close as possible
with an amateur
builder. Below is a front view showing the drag arms and the transfer pivot.
This version is too flimsy for the actual bike, but for some downhill
testing it was perfect.
This is the front heim joint for the drag arm
This is the rear heim joint for the drag arm
This is the ball joint for the upper control arm
This is the pivot for the upper control arm
This is the front heim joint for the drag arm
The placement of the drag links in relation to the control arms is critical
to prevent binding or bump steer. The drag link has to be parallel with the
upper control arm. Designing it to work took a lot computer time and head
scratching, but this layout did the trick. Now it's time to make it stronger
as well as better looking.
This is the rear heim joint for the drag arm
This mechanism is fairly simple but it took some thought. What you see is a lightweight
test version. It was cheap and easy, and having the right geometry made it work.
Here's how:The distance from the center of the transfer pivot to the
center of the drag arm's rear heim joint...
...must be the same distance as from the ball joint to the center of the
drag arm's front heim joint.
The centerline between the pivot points (shown
as red dashed lines) of the front lever must be designed at right angles to
the drag arm and parallel to the rear lever
The same rules apply with the linkage to the handlebars. As long as
everything lines up the forks and the handlebars
will be synchronized.
This is the transfer pivot between the forks and handlebars
This is the ball joint for the upper control arm
ProjectVF:
The Steering Mechanism
