When I buy new axle bearings they are always packed in grease slowing the axle down so I take a crock pot (my wife made me buy her a new one) and pour a 1/2 gallon of WD40 in it and let it get warm then place the bearings in there for a while and that melts the grease out of the bearings letting your axle spin much freer. You can also do this after cleaning them in heavy solvents works great. Pour the WD40 back into your gallon jug and it can be used again.
And then like Brock said when I’m at the track I spray Tri Flow in them between rounds.
