I'm looking at what it would take to buy my own PVC pipe and make my own PVC inserts for H1 HMMV wheels. Found the ID of a factory Mag runflat is about 16" with a width of 7-1/16" from another post on here... Looking up the specs of PVC pipe and an 18" Schedule 80 is roughly 16.014" on the ID and has a .937" wall (18" OD). Now the hard part will be to find a place that will sell 18" sch 80 pipe. But my guess this is the same stuff other vendors are using for the PVC inserts. Only down side I see is 33.5 lb/ft... so 19.5 lb for each insert. Anyone else tried this?