The tail wheel is definitely at risk, as is denting/twisting the deck. The heavy duty 5' Bush Hog brush mower that I have has withstood what the King Kutter would not. I bent back the wheel assembly on that one more than a couple times. I have used my brush mowers pretty hard including backing over some pretty large multiflora rose clumps and lower it down to take them out (when clearing land). Probably pretty tough on my PTO as well, but my JD 1070 has done pretty well over the last 30 years.