T&W: HPI Challenge 28R (4)HP 120032 HPI Racing HPI CHALLENGE TIRE 28R (MOUNTED 4PCS) The HPI Challenge 28R wheel and tyre set is intended for control spec racing, both indoors and outdoors. The HPI Challenge 28R tyre features a unique blend of rubber to deliver good traction with excellent durability. The wheel is a 24mm with 0mm offset, dish design moulded in a stiff plastic for improved high speed stability, and features a printed HPI logo to give the wheel a cool and unique