to belt the tires , you need to stop them from expanding so i used some duct tape on the insides of each tire. In my case they were mostly all off the rims anyway from a few speed passes....
basically took the tire off the wheel removed the tire insert, then turned the tire inside out (not as easy as it sounds ha!) then covered the inside with duct tape, be sure to put just one layer of tape and try to do all the tires as evenly as possible...then flip the tires back, reseat the inserts and re-glue to rims...