I have a 2003 TC24D with 31x13.5-15 turfs. Manual says you can dish in (narrow) or dish out (wide) the wheels, but it also references both 29x12-15 and 31x13.5-15 tires as the size for the turfs on the TC24D throughout the manual. I think the wider tires are on the newer machines and the manual was not completely updated to correctly reference the larger tires. The 13.5" wide tires on my 2003 are so wide, it came with them already dished out and they cannot be mounted any other way. If your wheels appear to be mounted dished in, you can turn them around for a wider stance according my manual.
Brad