I had bought these items and they don't last.
My first set lasted 2 races; I complained and RCMart replaced the defective part. Love RCMart! The drive pin keeps flying off in a crash and there is no rebuild kit. If you have to rebuild them after every race that would be a problem anyway.
I put the drives back in and one drive in the new set broke in 1 race.
Don't waste your money these are garbage.