Talked to an Exmark rep about doubles yesterday. He told me something about doubles I have never found on this site in all my searches.......To put doubles on a turf tracer (floating deck) you must replace the spindles with a different kind. The reason is turf tracer spindles have no washers to remove to raise the height of the blades in the housing. Put on a "shorter" spindle with washers that can be removed or added. Anybody with a TT replaced their spindles to put doubles on? I was ready to try it, not sure any more.