Have you ever experienced power hop? The condition where the tractor exhibits a severe bounce
or jump when pulling high draft loads in the field? After watching this video you will be able
to identify causes of power hop and adjust ballast and tire pressure to resolve power hop complaints.
There are several different factors that can increase the possibility of power hop. Some you
can control. Others you can't. Possible causes of power hop include dry soil on top of a firm base,
climbing hills, small tires, liquid ballast, too much weight on the front axle,
high tire pressure, tires on the same axle set to different pressures. There isn't much you can
do with the soil or the topography. Tires are normally chosen when the tractor is ordered
and are somewhat difficult and expensive to change once it is built. A good rule to follow is to order
your tractor with the largest tires possible. Large tires carry loads at lower air pressures which is
important to controlling power hop, not to mention reducing soil compaction. The first thing you need
to do is confirm that the front axle suspension, if equipped, is set to auto and that you have
the correct weight split and tire pressures for your application. If any of these are incorrect
get them fixed before doing anything else. See parts 1-4 in this video series for
ballasting and tire pressures. If the tractor is still experiencing power hop then start
increasing tire pressures. On 9R Series Tractors if operating faster than 5.5 miles per hour or
in soft soils increase the rear tire pressures in six psi increments until the power hop is resolved.
If operating slower than 5.5 miles per hour or in very firm soils increase the front tire pressures
until the power hop is resolved. Normally 12 to 18 psi above the rated pressure for the axle load
will resolve power hop. In either situation always make sure that one axle or the other is always at
rated pressures for the axle load. Never increase tire pressures on both axles at the same time
and don't exceed the maximum pressure imprinted on the sidewall.
If the tractor is still experiencing power hop after increasing tire pressures then remove
all liquid ballast from the tires and replace it with cast iron weights. On 7R or 8R
Series Tractors increase front tire pressures in 6 psi increments until the power hop is resolved.
Remember never increase above the maximum pressure rating that is imprinted on the tire sidewall.
Normally 6 to 12 psi above the rated pressure for the front axle load will resolve power hop. Power
hop can almost always be resolved by having correct weight splits and increasing tire
pressures as discussed earlier. However, if your 7R or 8R tractor is still experiencing power hop with
front tires at maximum tire pressure then the next step is to remove all the suitcase weights
but leave the tires at maximum pressure rating. If that doesn't fix it then fill the tires 75%
full of liquid ballast and re-inflate to 6 psi above the rated pressure needed for the axle load.
Lastly, if you have tried all of these tips and the problem still exists see your John Deere Dealer to
see if there is a malfunction that needs to be repaired. Remember almost all power hop problems
can be fixed by having the correct weight split and adjusting tire pressures. Now you are able to
identify causes of power hop and adjust ballast and tire pressure to resolve these complaints.