Have you been pulling the tractor hardIJ What do you have for weights and tiresIJ A freinds 8400 with MFWD, full front rack, and about 6000 lb of bolt on cast rear weight, and 18.4 46 duals still spins under heavy load before running out of HP. How does your 8100 put that much HP to the ground all day without burning up the tiresIJ