RE: Converted cox .049 reedies-Killer crank really necessary?
I don't think that all of the crankshafts break. But enough did and that caused people to make better crankshafts for the engines. it is possible that maybe people were overcompressing the engines and or running too large of a prop or too small of a prop. So it is really hard to say for sure.
So it depends on the luck of the draw so to speak. Now in looking at the heavy duty crank, I can see where it may be best to put one on the engine as the stock crank could let go on you.