If the trike steers uphill, it means its steering pivot gets pulled downhill by
the resulting weight forces acting on it. Uphill steer can be minimized by
moving the rear axle further forward, adding mass behind it, moving front wheel
closer to steering pivot or adding mass in front of it. I think the last point
is the easiest to achieve: all the rider needs to do is to put his feet back on
the pedals. Python's geometry counts on their mass being there and acts funny
if it isn't.
As to the pivot angle effect, I think we can't make any conclusions without
seeing the trike. There are many torques involved and they are not all directly
proportional to the angle.
On April 25, 2020 5:00:33 PM GMT+02:00, Patrick van Gompel
Not sure if I fully understand, but isn't this a common effect on
I think it depends on where the Center of Gravity is, but if that point
wants to go down (down the slope). Wouldn't that mean that your trike
wants to go up (up the slope)?
Or am I thinking to simplistic here?
Van: python-bounce@xxxxxxxxxxxxx <python-bounce@xxxxxxxxxxxxx> namens
Paul Needham <paul.2.needham@xxxxxxxxx>
Verzonden: zaterdag 25 april 2020 16:42
Aan: python@xxxxxxxxxxxxx <python@xxxxxxxxxxxxx>
Onderwerp: [python] Strange behaviour Python trike
My trike is a success and does about 1600 km a year.
A friend wanted to try and build one as well , however his has strange
behaviour ? he lives over 4 hours drive away and under the current
circumstances I cannot visit to try it for my self.
He has the ability to change the pivot angle about 10' either side of
the 60' he started with , mine is 56'.
These are his comments :
I have tried a few more simple runs up and down this lower end of my
street. I have taken the opportunity to coast “feet off” in all runs.
I have also taken the trike into the car park yard of the BT exchange
where there is no camber as such but the surface is sloped.
I have the following observations to impart:
1. If there is a slope or camber to the road the front end wants
to go UP the slope (towards the centre of the road).
2. The angle of the pivot magnifies this effect. More vertical
pivot = LESS turning force; more laid-back pivot = MORE turning force.
3. Trying this same coasting with feet off trick travelling in
the wrong direction up/down the road on the wrong side of the road the
Left/Right turn is reversed, the front end still wants to climb the
This rather suggests to me that it is the fluidity and “relative lack
of friction/resistance even when under load” of the pivot that allows
the behaviour to occur.
Any ideas what might be happening ?