What is in this article?:
One factor that can severely inhibit productivity is power hop — a bouncing effect a tractor sometimes experiences when pulling a high draw-bar load. By understanding what causes power hop, however, farmers can better diagnose the problem and make minor adjustments to correct it.
Overall tractor weight
Insufficient overall tractor weight for the horsepower is one of the major causes of power hop. Every tractor manufacturer has different recommendations on weight-to-horsepower ratios, but these recommendations generally fall somewhere between 100 lbs. per horsepower and 145 lbs. per hp. In other words, a 450-hp tractor should weigh somewhere between 45,000 and 65,250 lbs. Where your tractor falls within this range is dependent upon average speed during heaviest draft operations and whether the tractor is a mechanical front wheel drive (MFWD) or four wheel drive (4WD).
As a general rule, the slower the average speed of a tractor, the higher the weight-to-horsepower ratio should be. MFWD tractors generally have a higher recommended weight-to-horsepower ratio than 4WD tractors. So, a 4WD tractor traveling at high average speeds (5.5 mph or more) should fall within the lower end of the aforementioned weight-to-horsepower ratio spectrum, whereas a MFWD tractor traveling at low average speeds (4.5 mph or less) should fall within the higher end of the spectrum.
In order for a farmer to determine the most appropriate weight-to-horsepower ratio for his or her tractor, it’s best to consult with the tractor manufacturer, as each company’s recommendation will differ slightly based on type of tractor and average speed. If it is ultimately determined that the tractor is underweight, it is recommended that the farmer add cast ballast to achieve the proper ratio. Liquid ballast has been shown to increase tire stiffness, which can increase susceptibility to power hop.