JConcepts Tire Break-In Drill Adaptor Kit (Black) (12mm/17mm)Tire The JConcepts Tire Break In Drill Adaptor Kit was developed for 1 10 and 1 8 tire break in. This simple combination of a standard hex drive shaft for a typical drill, has been extended and given some lock driven flats to make it a very useful tool around the track. An aluminum 12 and 17mm hex adaptor slides over the shaft to give racers the option of which type of vehicle (1 10th or 1 8th) they are preparing tires for. The flywheel nut features a