Is "As good as it gets" good enough?

Joined
May 31, 2013
Messages
3,705
Location
South Benfleet, Essex, England, UK
The recent trip to Holland brought an issue on the trike into fairly sharp focus.
The issue? - Turning circle of an Oil Tanker.
Now obviously, no tadpole is going to have a turning circle to a Python trike (the immediately available comparison) or a delta trike for that matter but some must be better than others.

Last week I took a long hard look at the steering system (dual link) and it was evident that there was steering system to frame interference that was limiting the range of the steering mechanism and these interferences could readily be eliminated.
  • I turned the handlebar receiver tube around 180 degrees in the gooseneck to place the handlebar pinch-bolts forward instead of rearward, because the pinch-bolts were restricting travel by hitting the seat mount cup.
  • I cut excess length off the studs that anchor the steering track-rods in order that they could NOT foul on the frame anywhere as they swung across the keel of the trike.
There was an immediate and visible improvement in the "full-lock" angles of the wheels (to the naked-eye).

But was it enough of a change to improve things?

I had not taken any before measurements but it had been obvious in Holland that there was a significant issue (especially when towing the trailer), but also without the trailer that resulted in dismounts and picking the rear of the trike up to turn 180 degrees on a narrow track (several times a day).

I took the trike out early this morning to a largely deserted car park and executed some 180 degree turns while running a wheel along the line markings.
The best I can now get is a 5.6M diameter turning circle.
I came back and checked what else might be possible, and I cannot see that there is any more to be gained.
The track rods are in a straight line under the handlebar axis (so they are at their "best possible" steering input with nothing further to be gained) past this point they would be fighting to pull the steering back to centre.
When you apply excessive force on an individual wheel it is evident that the links are not moving any further and you are just taking all the "slack/play" out of the steering system and in fact the rose joint shell on the track-rod is then making contact with the seat-mount pedestal on the frame.

So it seems to me that without major surgery we are now at least getting the best possible out of the system.
But will it be enough?
 

Radical Brad

Garage Hacker!
Staff member
Joined
Mar 13, 1999
Messages
6,060
Location
Kakabeka Falls, Ontario, Canada
If this is just about turning around in a small space at very low speeds, how about a creative articulated rear triangle that can unlock (front end loader style)?
It would be a can of worms mod, but cool, and you would probably be the first to try it.

Brad
 
Joined
Feb 7, 2008
Messages
4,185
Location
Nottinghamshire England
Not sure any measurements are really needed ?
Either it is agile enough in the riding environment or it isn't ?

Also see here :-BROL however where are they measuring from ? are they all taking about radius/diameter ?

Of course if you INSIST on a tadpole there are some that CAN turn ?
and no I don't endorse this trike or lean steer trikes.
Go there at your peril....

Paul
 
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