Fluid, Cast Iron Weights, and More…….
The Infernal Debate: Tractor Ballast, Fluid Versus Iron Weights!
We want to make it clear at the outset; there is not really a hard and fast fluid versus weights rule or school of thought. Both ballast options have their place and both often work together to achieve the same goals.
Years ago, when most tractors were 2-wheel drive, used rubber tubes in bias ply tires, and had far less horsepower than today’s models; fluid was a very good and economical method to add ballast weight to tractors. Today, in large, high horsepower, 4-wheel drive tractors running radial tires, fluid as ballast is not nearly as common. Fluid does, when set up correctly, remain a common and viable option in many utility and compact tractors.
⚠ When Choosing and Installing Additional Ballast: ALWAYS refer to the recommendations contained in the owner’s manual for your equipment. ALWAYS refer to the maximum load rating of your tires.
Jumping right in, these have been our experiences and observations:
Radial Tire treads and sidewalls work independently of each other. This allows the footprint to lengthen and widen under load and the tire lugs remain stable through the footprint. Most of the flexing will occur in the sidewalls. Using fluid in radial tires inhibits the deflection of the sidewalls and decreases performance. Fluid successfully defeats the design characteristics intentionally built into the tires. If you have invested in radial tires, iron ballast (if additional ballast is required) should be used to maintain the intended performance.
Bias Ply Tire treads and sidewalls work as one unit. This causes the lugs to move and shift under load. Generally, these types of tires will NOT make continual flat contact with the ground and the smaller area of contact will contribute to higher ground bearing pressure. The crisscrossed body plies do offer much stiffer sidewalls than do radials. Since sidewall deflection is not as much of an issue as it would be on radial tires, the negative influences of liquid ballast is reduced. Fluid (when set up correctly) can be used effectively in many applications with bias ply tires. In some circumstances the added weight can increase the area of the footprint and provide for flatter ground contact. This can also be achieved with cast iron weights.
Fluid filled tires will ALWAYS provide a rougher ride than will air filled tires.
Fluid filled tires do not perform well on hard surfaces or at higher speeds.
Fluid filled tires are harder to set up correctly than are iron weights with air filled tires.
Fluid as ballast is cheaper initially than are tractor weights. We do find that iron weights hold their value very well over a long period of time whereas fluid is simply an expense. In another blog article we spoke about the value of iron weights over time:
In 1973 we sold 100 pound front tractor weights for $13.50 each. You could have used that weight for 48+ years and sold it for far more than you paid for it.
In 1997 we sold this (still popular and currently produced) style wheel weight for $38.10. Twenty+ years later it will bring a lot more than its original purchase price on the used market.
In summary, iron ballast is the preferred option of most tire manufacturers. Iron ballast can be adjusted to the work required whereas fluid levels are hard to adjust. Many owners of large tractors use their machines for various types of work with differing loads and differing speeds where the flexibility offered by iron weights is very important. Many utility tractor owners and tractors equipped with front-loaders are doing the same type of work day in and day out. Fluid can be effective and economical in these tractors running on bias ply tires. This is especially the case on 2-wheel drive tractors.
Owners of tractors with radial tires should avoid fluid as ballast in most circumstances.
Owners of tractors with bias ply tires should consider the variety of jobs they want their tractor to perform, their ground conditions, their normal operating speed, and their average required ballast amount before making a decision.
This is an abridged blog post of general information. We could go into much more depth regarding:
- Compensating for Hydrostatic Head in Fluid Filled Tires
- Pressure and Volume Changes Due to Deflection
- Tire Slippage on Rim
- Operations on Turf
- Power Hop, Duckwalk, Yaw, and Road Lope Issues
- Lost Horsepower Potential
- Ground Bearing Pressure
- Using Both Liquid and Iron Ballast Together
As always, we invite you to contact us regarding your specific situation and equipment. We routinely recommend iron weights, liquid ballast, and sometimes we recommend doing nothing as you may already have your tractor set up for optimal performance.
This blog is general information only, representing the opinions of the author, and does not cover all aspects of the subject matter. Use of the information contained herein is voluntary.
