Identifying and Replacing Rims on Klein KPT Water Tower Trailers

[MikePhua]

Klein Products and the KPT Series Legacy
Klein Products, founded in the mid-20th century, has long specialized in water distribution systems for dust suppression, compaction, and fire control in mining and construction. Their KPT (Klein Portable Tower) series includes mobile water towers designed to refill water trucks quickly in remote or high-volume operations. These trailers are often seen on large infrastructure projects and quarries, where water logistics are critical.
The KPT 105 and KPT 120 models are among the more common units, though they vary in age and configuration. Older models, especially those built before the 2000s, often used truck-style running gear sourced from whatever was available or economical at the time. This has led to a mix of wheel and rim types across the fleet, complicating maintenance and parts sourcing.
Terminology Annotation
- Budd Wheel: A type of wheel mounting system using inner and outer nuts on dual wheels, common on heavy-duty trucks.
- Dayton Wheel: A spoke-style wheel system using wedges and nuts, often found on older trucks.
- Hub-Piloted Wheel: A modern wheel system using a single nut with a built-in washer, centered by the hub rather than the studs.
- Bolt Circle Diameter (BCD): The diameter of the circle formed by the centers of the wheel studs.
- Lug Nut Configuration: The arrangement and threading of nuts used to secure the wheel to the hub.
Challenges in Rim Identification
When acquiring an older KPT 105 trailer, one of the first challenges is identifying the correct rim and tire combination. Descriptions may list tire sizes like 9.00-20 or 10.00-20, but these do not confirm the rim type or bolt pattern. Visual inspection may reveal only three visible lug nuts, leading to confusion about whether the wheels are Budd-style duals or single-mount truck rims.
In one case, the trailer appeared to have Budd wheels but lacked the inner stud typically used for dual mounting. This suggests a single-wheel Budd configuration, similar to front axles on older two-ton trucks from the 1970s. These wheels use outer-style nuts with smaller inner threads, and they mount directly to the hub without the inner nut/stud combination found on duals.
Field Strategy and Practical Solutions
To prepare for transport or field use, operators often mount spare tires in advance. One approach is to fit 11R22.5 tires onto old-style Budd rims with double-nut configurations. If the trailer uses single Budd wheels, these rims will still fit, provided the lug nut threading and diameter match.
Recommended steps for rim identification and preparation:

• Measure bolt circle diameter and stud count
  
• Inspect hub face for pilot centering or stud centering
  
• Check lug nut threading and compare to standard Budd specs
  
• Confirm tire bead seat dimensions to match 22.5-inch tires
  
• Carry spare rims with matching offset and center bore
  

If the trailer uses hub-piloted wheels, the nuts will have built-in washers and the wheel will center on the hub. These systems are more common on post-2000 trailers and offer easier maintenance. However, older trailers may use a mix of Budd and Dayton wheels depending on prior ownership and regional availability.
Manufacturer Records and Historical Gaps
Klein Products did not consistently archive build records for older trailers until the mid-2010s. This means that trailers built before that period may lack documentation on rim type, axle configuration, or tire size. Operators must rely on physical inspection, parts catalogs, or comparison with similar units.
Some dealers and salvage yards maintain records of common configurations. For example, a 1999 KPT 120 may have Budd wheels with inner and outer nuts, while a 2014 model likely uses hub-piloted wheels. These trends can guide expectations but should not replace direct measurement.
Anecdotes and Lessons from the Field
One operator in North Carolina purchased a KPT 105 trailer from an auction site and drove four hours to retrieve it. Without clear rim specs, he brought a set of 11R22.5 tires mounted on Budd-style rims and hoped for compatibility. Upon arrival, he confirmed the trailer used single Budd wheels with no inner studs, and the spares fit perfectly.
Another technician in South Carolina noted that older Klein trailers often used whatever truck axles were available at the time—sometimes even mixing Budd and Dayton wheels on the same unit. His advice: always bring a thread gauge, caliper, and spare nuts when inspecting unknown trailers.
Recommendations for Future Maintenance
To streamline rim and tire management on Klein water tower trailers:

• Create a reference sheet with rim type, bolt pattern, and tire size for each unit
  
• Standardize wheel systems across the fleet when possible
  
• Replace mixed wheel types with uniform hub-piloted systems during axle rebuilds
  
• Keep spare rims and tires labeled by trailer model and year
  
• Train operators to recognize Budd vs. hub-piloted configurations visually
  

For long-term reliability, consider upgrading older trailers with modern axles and wheel systems. This reduces confusion, improves safety, and simplifies sourcing parts in the field.
Conclusion
Rim identification on Klein KPT water tower trailers—especially older models like the 105—requires a blend of mechanical knowledge, field experience, and historical awareness. With inconsistent documentation and evolving wheel standards, operators must rely on direct inspection and practical adaptation. Whether hauling water across a dusty jobsite or preparing for transport, the right rim makes all the difference—and knowing what’s under the trailer is just as important as what’s on top.