Kent, when I look at your build.I imagine things like this.one I found.on the 'net.
Both are edgy and I imagine take a lot of trial and error. Your's is more of a slingshot than this because your rider is behind the rear axle. I wonder if it might balance out if you have the passenger get on first.
Brings the wheelbase to 73 ".
Still a bit less than the 76" I first planed on.
Too long to make a u-turn without planning.
Long enough to stop the 1/4 backflip ?
Should be, the rear seat will stay about where it was.
Moving the rear BB back also, should leave a bit more room for the front seat.
The 4th, 5th, and 6th test rides went great.
Considering that almost everything on this build is recycled, and that the "engineering" is
and has been " guess engineering" from the start, it's a small miracle that it works at all.
I am liking the results. UpDown 2 is worth finishing.
Next part to add is a strong backrest.
It also looks like the 'Up" is not going to be as "Up" as I drew it, and the "Down" is going to
be higher than I wanted.
But that's OK, and the lower rear seat means that feet on the ground can be used for reverse.
Also, very stable with 20" wheels and lower seat.
This build looks much bigger in pics without any riders.
To put the size into perspective , I will post one of me.
Or, make the front seat on a "quick release" tube, just flip the release, pull off the seat,
slip on the basket, and go shopping.
With some kind of notched brace resting on the front of the frame for support.