my b4.1 has never broken an axle pin, but my 17.5 sc10 has broken 2, never again since i put on the jc hex conversion. however my 10.5 sc10 broke one even with the hexes, the worst part is that it was during a battle for 1st in the a main. i ordered the FT solid axle pins for both my sc10s so that never happens again, hopefully.