Control Power Hop - MFWD

Power hop is a condition where an MFWD machine without suspension exhibits severe bounce and/or pitch motions at field working speeds when pulling a towed implement. It can occur when pulling medium to high draft loads in loose, dry soil on top of a firm base and/or when climbing hills. As a result, machine cannot maintain pull due to either loss of traction, rough ride or both. Adjust only after assuring guidelines for optimum performance with towed implements have been followed. They are:

• No more than 40% of weight can be on the front axle.
• If liquid ballast is used in rear tires, do not exceed 40% fill (4 o'clock valve stem position).
• Front and rear inflation pressures are set correctly based on static axle loads.

Then if power hop occurs:

1. Increase front inflation pressures by 40 kPa (0.4 bar) (6 psi) and operate machine.
2. If power hop still occurs:

   Increase front inflation pressures by another 40 kPa (0.4 bar) (6 psi) and operate machine. Increase front inflation pressure as needed, up to a maximum of 40 kPa (0.4 bar) (6 psi) above the maximum pressure rating for tires. Usually 40--80 kPa (0.4—0.8 bar) (6—12 psi) above rated pressure for front axle load suffices to control power hop.

3. If power hop still occurs:

   Remove all front ballast weights. Leave same front maximum inflation pressure from previous step and operate machine.

4. If power hop still occurs:

   Install 75% liquid in front tires. Reinflate front tires to the maximum pressure rating for tires and operate machine.

NOTE: In most cases, step 4 is not required to control power hop.