Yikes I better look into that I even have them on my 1/3 scale Cubs and have had for yrs..According to everything I read they wear 4 times longer but I havent read anything on them for some time now...I have never had one fail but a big Cub is pretty easy on them usually. I have 645 MG's on my 1/5 scale cub and they work great. They are just noisy..The gears are not quite the same stuff as the gears in a diff or a tranny though..If they were they would never wear out..Thanks for the heads up..I am going to do some research on this...