zero roll explained please

[S Lathrop]

Thanks, your comments are helpful. When I asked about zero roll I was thinking of anti squat which if I understand it correctly keeps the tail from drooping under acceleration. And it is done with the suspension geometry I believe.

As for cambering the rear wheel I agree it would help in cornering. I think trying to cause camber change on the swing arm/drive wheel would be impractical. One possibility is to lean the whole monocoque from the front. A passive system would be to use Ackerman and a lot of caster to cause the inside wheel to drop the inside of the trike. An active system might work by giving the lower control arms a single center pivot. The steering arms would then be fixed to the chassis. And the steering rack would be connected to the upper joint of the spindle. It might be necessary to use power steering I don't know. It might be possible that the centrifugal force would right the chassis as you exit a corner. It needs to be drawn and modeled.

I was also planning to use those huge rear tires they put on Harley's. The tire has a round profile so it would not provide roll resistance. I would use the biggest one I could find for the rear. Mount it on a 'wide five' race wheel which could be bolted to a Honda Comstar hub pretty easily using a flat aluminum adapter plate. You can use some smaller rear tires on the front you just flip them around so the tread pattern works for braking rather than acceleration. They come in 15's so car wheels would work on the front.

Decades ago, Ed Zink designed a F440 where the engine and rear axle were mounted on a separate frame. That frame in turn was mounted so it could rock laterally relative to the rest of the chassis where the driver and front suspension were mounted. You could do the same thing. and rig a system that as the forward portion of the chassis rocked in one direction the rear section, engine and rear drive would move in the opposite direction. You would control the movement with a torsion bar.

[R. Pare]

You might also think about a mechanism like what is used on swinging doors to re-center them - a sloped surface that the arm the shock is attached to that raises the inside tire and lowers the outside tire when the steering is turned, cause the trike to lean towards the inside ( or, at the minimum, counteract some of the leaning to the outside). thought about this a couple decades ago, but never got to play with it.

If you design the trike so that the front end can pivot relative to the rest of the assembly, you cou force the back end to roll inwards with a mechanism attached to the handle bars - turn left or right, and the back end rolls into the corner. Could be a very simple linkage.

[mr2racer]

You might also think about a mechanism like what is used on swinging doors to re-center them - a sloped surface that the arm the shock is attached to that raises the inside tire and lowers the outside tire when the steering is turned, cause the trike to lean towards the inside ( or, at the minimum, counteract some of the leaning to the outside). thought about this a couple decades ago, but never got to play with it.

If you design the trike so that the front end can pivot relative to the rest of the assembly, you cou force the back end to roll inwards with a mechanism attached to the handle bars - turn left or right, and the back end rolls into the corner. Could be a very simple linkage.

Yes!

I'm using a D15 civic engine from a '94. The car had the option of power steering. So there is a pump and bracket available. If the steering plane is at the top of the chassis. And if I add a second set of steering arms to the spindles on the opposite side from those attached to the rack. And a tie rod from them to the chassis it will roll the bike inwards giving the rear wheel negative camber. The harder the turn the more negative camber on the rear tire. I would limit the roll to about five degrees, I think.