D Borland
Elio Aficionado
with a limited engineering background, I would think the turning radius would be dependent on several safety factors. A three wheeler should not have the ability to too easily roll at higher speeds. if the ability to turn too sharply exists, the manufacturer opens themselves up for some significant liabilities for poor design. This is perfectly acceptable to me. A tryke bike has a similar problem with a larger turning radius. Better safe than sorry.