In my own opinion, I've seen most axles fail at the base of the splines. I one picture from classic is a result of over torquing the axle nut! The pictures I posted are several examples I complied from members here, let alone other's that haven't posted pictures! Most if not all of them caused by drag racing style launches. But then it all depends on the loads people place on there cars. I'm sure if John C were to comment, he would say that weld joint at the base would be the weak link to the axles, since road racing would place a higher load on that part of the axle. So it all depends!