Guys, I think Vikingstaff might have it right as I tried a Enertia 15x15 this weekend and the motor is still pulling 6000 RPM and speed is at 44.5 with my wife and I and 1/2 tank of gas. I wonder if the enertia eco 16x17 would keep my rpm's in the range or not or just go with the 14.5x17...