Tony Belding wrote:
I've noticed some tadpole trikes (like the Scarab/Trimuter) are
available in a "big wheel" version with a larger rear wheel. They
obvioulsy take up more space. . . I was just wonder what was the
reasoning behind that, what the advantages are presumed to be. Smoother
ride? Higher gear range?

Also Logo Trikes offers trikes in big wheel and small although they
generally do this to certain market preferences. The Japanese like big
wheels, go figure, others maybe not so. I myself went by Greenspeed's
assertion that same-sized wheels all round is better for stability and
handling.

I would think that the advantage for which people are willing to
compromise steering and handling, and carry odd-sizes in tubes, is that
you don't have to gear up to compensate for that smaller rear wheel.
This means less need for Schlumpf drives, 3x7 internal rear hubs and
other friction-causing drivechain devices, or for dinnerplate chainrings.

I have also seen some homebuilt bigwheeled trikes where all wheels are
700C and for a groundhugging tadpole this is a dubious arrangement.
Consider the forces applied to the front wheels in turning. The rear
wheel doesn't suffer so badly of course.