Alternating Track Pad Types on Excavators: Traction, Terrain, and Tactical Design

[MikePhua]

Introduction: A Curious Undercarriage Configuration
In the world of earthmoving equipment, undercarriage design is often standardized for durability and performance. However, a 2019 Caterpillar 326FL excavator spotted in Ohio featured an unusual configuration: alternating track pad types. This setup—where different pad styles are installed in a repeating pattern—raises questions about traction, terrain adaptation, and operational strategy. While rare, this approach has historical precedent and practical logic in specific applications.
Terminology Explained

• Track Pad: The individual plates bolted to the track chain of a crawler machine, responsible for ground contact and traction
  
• Triple Grouser Pad: A pad with three raised ribs, offering balanced traction and maneuverability
  
• Flat Pad: A smooth pad often used on paved surfaces to reduce damage
  
• Swamp Pad: A wide pad designed for soft, marshy terrain, increasing flotation
  
• Alternating Pad Configuration: A pattern where different pad types are installed in sequence, such as triple grouser followed by flat pad
  

Why Alternate Track Pads?

1. Enhanced Traction on Slopes
   • In pipeline work or steep terrain, alternating pads may improve grip. For example, triple grousers dig into soil while flat pads reduce drag, creating a hybrid traction profile.
     
2. Reduced Ground Disturbance
   • On sensitive surfaces like turf or reclaimed land, alternating pads can minimize damage. Flat pads distribute weight while grousers provide directional control.
     
3. Noise and Vibration Damping
   • Mixed pad types can reduce harmonic vibration and noise, especially on hard surfaces. This is useful in urban excavation or near sensitive structures.
     
4. Custom Wear Management
   

• Operators may alternate pad types to manage wear patterns. For instance, harder pads in high-wear zones and softer pads elsewhere.
  

Historical Context: The Pipeline Strategy
In the 1980s, pipeline contractors in Alberta experimented with alternating swamp and triple grouser pads on sidebooms and excavators. The goal was to maintain traction on muddy slopes while reducing the tendency to sink. The method proved effective in spring thaw conditions, where terrain consistency was unpredictable.
Technical Considerations and Parameters

• Machine: Caterpillar 326FL
  
• Track pad width: Typically 600–800 mm
  
• Pad bolt pattern: Must match across pad types
  
• Grouser height: Varies by pad type; affects ground penetration
  
• Terrain: Mixed—slopes, clay, gravel, reclaimed land
  

Installation Tips

• Ensure all pads share compatible bolt spacing and curvature
  
• Alternate pads symmetrically to maintain balance
  
• Torque pad bolts to manufacturer spec (usually 300–400 Nm)
  
• Monitor wear weekly to detect uneven degradation
  
• Avoid mixing pad types with drastically different thicknesses
  

Field Anecdote: The Manitoba Experiment
A contractor in Manitoba retrofitted a Komatsu PC210 with alternating flat and triple grouser pads for work near a hydroelectric dam. The terrain included riprap, clay, and concrete. The configuration allowed the machine to transition between surfaces without changing pads or damaging infrastructure. Operators reported smoother travel and better control on embankments.
Pros and Cons of Alternating Pad Types
Pros:

• Improved traction in variable terrain
  
• Reduced surface damage
  
• Potential noise reduction
  
• Customizable wear strategy
  

Cons:

• Uneven wear if not monitored
  
• Slightly more complex installation
  
• May confuse service technicians unfamiliar with the setup
  
• Limited OEM support for mixed configurations
  

Recommendations and Solutions

• Use alternating pads only when terrain demands it—standard configurations suffice for most jobs
  
• Document pad types and positions for future maintenance
  
• Train operators on handling mixed traction profiles
  
• Consult undercarriage specialists before retrofitting
  
• Consider aftermarket pad suppliers for custom configurations
  

Conclusion: Tactical Traction for Specialized Tasks
Alternating track pad types may seem unconventional, but in the right context, they offer tactical advantages. Whether climbing slopes, crossing mixed terrain, or minimizing surface impact, this setup reflects the ingenuity of field operators adapting machines to real-world challenges. While not a factory standard, it’s a reminder that customization often drives innovation in heavy equipment.
As one pipeline foreman once said, “If the ground won’t cooperate, make your tracks smarter.”