Shells

Im needing to find somewhere thats sells wheel shells. Ive got a set of 20" 3 peice Work rims and i want to buy some wider shells, can anyone point me in the rite direction?Im running 20" x 8.5" fronts and am wanting to widen the rears to suit my new narrowed frame, the wheels are too expensive to buy new rears so thats why im looking at the option of buy the wider shells and swapping my centre over.

im sure any one of the billet wheel manufacturers should be able to help you out, Because they do stock raw hoops in various widths and sizes.