Solving Rim Offset Mismatch on the Mustang 960 Skid Steer

[MikePhua]

The Mustang 960 and Its Design Legacy
The Mustang 960 skid steer loader was part of Mustang Manufacturing’s push in the late 1990s to offer high-performance compact equipment for contractors, landscapers, and municipalities. Mustang, founded in 1865 and later acquired by Manitou Group, built a reputation for durable machines with straightforward mechanical systems. The 960 model featured a rated operating capacity of around 1,800 lbs, a robust hydraulic system, and a four-wheel drive layout with 8-lug wheels—making it a popular choice for mid-sized job sites.
By the early 2000s, Mustang had sold thousands of 960 units across North America. Its wheel and tire configuration was designed to balance stability, maneuverability, and compatibility with tire chains or flotation tires. However, rim offset—often overlooked—plays a critical role in maintaining proper clearance and steering geometry.
What Is Rim Offset and Why It Matters
Rim offset refers to the distance between the wheel’s mounting surface and its centerline. It determines how far the wheel sits inward or outward relative to the hub. There are three main types:

• Positive Offset: Mounting surface is closer to the outside of the wheel, pushing the wheel inward
  
• Negative Offset: Mounting surface is closer to the inside, pushing the wheel outward
  
• Zero Offset: Mounting surface is centered, balancing the wheel equally on both sides
  

On skid steers like the Mustang 960, incorrect offset can cause tires to rub against the frame, affect turning radius, and even lead to premature tire wear. In one case, a mismatched rim caused the inner sidewall of a tire to grind against the loader frame during turns, exposing the cords and requiring early replacement.
Identifying the Correct Offset for the Mustang 960
The factory rim for the Mustang 960 is typically a 16.5 x 9.75-inch steel wheel with 8 lugs. The correct offset ensures that the tire clears the frame and maintains proper alignment. Measurements taken from original rims showed:

• Outside spacing (valve stem side): approximately 5.25 inches
  
• Inside spacing (hub side): approximately 5.75 inches
  
• Calculated offset: roughly 0.25 inches inset
  

This configuration keeps the tire centered enough to avoid rubbing while maintaining a stable stance. A replacement rim with 4 inches outside spacing and 7 inches inside spacing would result in a 1.5-inch inset—pushing the tire too far inward and causing interference.
Finding a Matching Rim and Avoiding Common Pitfalls
Aftermarket rims often vary in offset, even when labeled with the same size and lug pattern. Some suppliers list “universal” rims that may not match the original geometry. To avoid mismatches:

• Measure both inside and outside spacing with a straight edge and tape measure
  
• Confirm bolt pattern and center bore diameter
  
• Look for stamped part numbers on original rims (e.g., 215216595)
  
• Contact manufacturers or suppliers with exact measurements, not just model numbers
  
• Consider zero-offset rims if unsure—these often provide the safest clearance
  

In one successful case, a zero-offset rim was sourced from a supplier specializing in skid steer wheels. The new rim matched the original three and eliminated the rubbing issue entirely.
Can You Flip the Rim to Adjust Offset
Some operators experiment with flipping rims to change offset. While this can work in certain agricultural applications, it’s risky on skid steers. Flipping may:

• Alter valve stem accessibility
  
• Cause imbalance or stress on wheel bearings
  
• Shift tire position too far outward, affecting fender clearance
  
• Void manufacturer recommendations and safety ratings
  

Unless the rim is designed for dual-mounting positions, flipping is not recommended. Always verify with the supplier or manufacturer before attempting this workaround.
Where to Source OEM or Compatible Rims
Finding a matching rim for older machines like the Mustang 960 can be challenging. Options include:

• Specialty suppliers like Prowler or Solideal
  
• Salvage yards with Mustang or Gehl inventory
  
• Online marketplaces with detailed offset listings
  
• Local tire shops with access to industrial wheel catalogs
  
• Mustang/Manitou dealers with legacy parts access
  

When contacting suppliers, provide:

• Rim size (16.5 x 9.75)
  
• Lug count (8)
  
• Measured offset (inside and outside spacing)
  
• Machine model and serial number
  

In Louisiana, an operator located a matching rim by referencing the offset directly rather than relying on model compatibility. This approach bypassed catalog discrepancies and ensured a proper fit.
Conclusion
Rim offset may seem like a minor detail, but on machines like the Mustang 960, it can make the difference between smooth operation and costly damage. Understanding how offset affects tire clearance, steering geometry, and wear patterns is essential for safe and efficient performance. By measuring carefully, sourcing intelligently, and avoiding shortcuts like rim flipping, operators can maintain their machines with confidence—even decades after production. The Mustang 960 may be a legacy model, but with the right rim, it still runs like a champ.