Controlling Power Hop (MFWD tractors without front suspension)

Power hop is a condition where tractor 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, tractor cannot maintain pull due to either loss of traction, rough ride or both. Make adjustments only after assuring guidelines for optimum performance with towed implements have been followed. They are:

• No more than 40% of weight can be on front axle.
• If liquid ballast is used in rear tires, it should 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 0.4 bar (6 psi) and operate tractor.
2. If power hop still occurs:

   Increase front inflation pressures by another 0.4 bar (6 psi) and operate tractor. Continue to increase front inflation pressure as needed up to a maximum of 0.4 bar (6 psi) above maximum pressure rating for tires (imprinted on tire sidewall). Usually 0.4—0.8 bar (6—12 psi) above rated pressure for front axle load will suffice 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 tractor.

4. If power hop still occurs:

   Install 75% liquid in front tires. Re-inflate front tires to maximum pressure rating for tires and operate tractor.

NOTE: In most cases step 4 will not be required to control power hop.