42MM Plastic Eccentric Single Groove Pulley DIY Toy Car Wheels Dia.42mm TH=6mm Bore Hole Aperture:2MM 1.95MM Yellow With TT Flat Hole 422A2AB. 42MM2A Plastic Single Groove Pulley Bore 2MM 1.95MM TT Flat Hole Eccentric 2.1MM FD490.
eBay