I’m a newbie , I have a 1/18 ruckus and wanted to upgrade to a brushless system . I got the hobbywing EZRUN 18T 5200kv system . I replaced the stock motor with the new one , however the stock pinion gear does not fit on the hobby wing motor shaft . The shaft size is 2mm and the stock one is 5 mm . Can anyone give me some advice on where to get the same stock pinion gear with a 2mm bore .. the pinion gear is 14T 48P ?