Tom_H
Veteran Member
Any mass added to the rears increases backtip tendency during acceleration. This is because the mass is above the tire contact patch where the accelerative force is delivered. Same idea on a slope, where a component of G provides the acceleration force even if the tractor is not gaining speed. If it is gaining speed its a double whammy.
larry
I completely see what you are saying. The extra mass in the tires gives extra inertia to overcome during acceleration. Some of the torque which would have gone towards ΔV is transmuted into energy that rotates the entire Tractor/BH combination on the rear axle. (One might visualize the tractor with the rear wheels locked in huge vice clamps. When acceleration is applied, the tractor can't move foward, so the energy applied to the axle rotates the tractor instead-like a motorcycle or drag racer rearing up with the front wheel(s) off the ground.) If the tractor is already on a slope, the front end is already partially lifted, the CG is higher, and less vectored force is required to pivot the tractor on the rear axle. (This would not happen an a FWD automobile, but does happen on a tractor in RWD. Even in 4WD, most of that energy goes into the rears anyway.) Concurrently, (on the slope) the now vectored force of G increases the resistance against ΔV in an uphill direction, making the rotation of the rig require still less energy. Excellent points! Thanks!!
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