Pro Axle inline crowns are an innovation for slot racers. These extremely high mechanical precision couple show a unique feature: the set hexagonal screw locking is coupled,  for the first time in slot racing, to the self centering thread where the motor axle is inserted, like in all modern Euro 1/32 slot cars (patent pending). The self lubricating polimer that makes up the crown guarantees maximum smoothness together with the optimal gear shape, optimised in several months research. The threaded insert is in bronze (for all uses) ar aluminium (for extremely high performance racing - it is mandatory to lube the thread before every usage and with regularity), and the low tolerance of the thread keeps the pinion and the gear at the optimal gearing distance. Perfect with Slot.it pinions and with the pinions that are normally used on cars out of the box (we recommend using brass pinions)