REGARDING Original and Version2 "Chrome" TRIKKE 8:

There is a lot of interest in converting silver-frame (aluminum) T8 version one and T8 version two Trikke 8's to all-air. 

The air tires will not fit on the rear axles because they're larger (8.5in) than the 8in polyurethane wheels that come on those Trikkes.  Some of the front forks, however, are long enough to accomodate an air tire, which would improve carving via increased traction. 

A Trikke 8 Convertible (black aluminum frame, Fall 2005 or newer) can be converted to all air, but you would need three air tire assemblies and no spacers.  There are two sets of holes on the T8 Convertible frame to accomodate for the different wheel sizes, in order to move the brake pad accordingly; this is not the case with the silver frame (non-convertible) Trikke.