Azub TRICON has the ideal positioning system where the individuals can dial in the trike to fit them.  Azub has a wide range of options for their trikes.  The TRICON has rear suspension to take the bumps out of the ride.  With the 26" rear wheel, this Azub gives you greater stability, comfort, and slightly rolling resistance.  The TRICON comes with a 157 mm Syntace X-12 solid axle with the normal external gearing.  Other gearing options such as Alfine, Dual Drive, or Rohloff comes with 135mm spacing.  Complete specs can be found HERE