I picked these up for my 1/10 Tamiya TT01 type E mustang. They are 12mm hex, hard plastic and work great. https://www.ebay.com/itm/4pcs-Hard-Plastic-1-10-On-Road-RC-Drift-Car-Drift-Wheels-1-9in12mm-Hex-round-/393077840393?mkcid=16&mkevt=1&_trksid=p2349624.m46890.l49286&mkrid=711-127632-2357-0