I want to regrease and adjust the wheel bearings on my 2012 Giant Escape 2 and after removing one of the cones and measuring, I'm still confused on which cone wrench to purchase. There are 4 flats on the cone. The measurement across 1 set of flats is .500" and the other set is .541". It would appear I need a 1/2" cone wrench but all I can find on Amazon is metric cone wrenches. Could somewon help a wannabe bike mech. out?