4N Grouser Bars Explained

[MikePhua]

What Are 4N Grouser Bars
4N Corporation is a well-known manufacturer of grouser bars, which are metal bars welded or bolted onto the track shoes (or "track links") of crawler‑type machines (dozers, excavators, etc.). These bars help restore or build up the “grousers”—the raised bars that dig into the ground, giving better traction and extending the life of worn track shoes.
Popular Sizes (Sections) Offered by 4N
4N produces multiple “sections” (sizes/shapes) of these bars, each suited for different machine sizes:

• Section 820: Smallest size — good for compact machines or very small track shoes. (~ 25.4 mm length, 15.9 mm wide)
  
• Section 840: Very common — widely used on smaller track dozers (e.g., Cat D5/D6). (~ 35.1 mm × 19.1 mm)
  
• Section 850: Taller bar, commonly used for mid-size dozers like D6 / D7.
  
• Section 870: Larger still — typically for big dozers like D8 / D9.
  
• Section 890: Very wide cross-section; available in both regular and heat-treated versions for extreme use or older, large machines.
  

Why Use 4N Grouser Bars?

• Cost Savings: According to 4N, welding grouser bars to worn shoes is often much cheaper than replacing entire track shoes.
  
• Extended Machine Life: By “re-grousering” worn shoes, you can significantly increase a machine’s undercarriage life, which is often one of the biggest maintenance costs.
  
• Reduced Downtime: Using replaceable bars means less time in the shop — instead of waiting for full track‑shoe replacements, you can restore grip relatively quickly.
  

Trade‑offs and Considerations
From field reports:

• Some mechanics raise a concern: do not weld the bars taller than the original grouser height, because building it up too high can stress other undercarriage components.
  
• One user mentioned using an alternative brand ("Dura‑Tuff") on a D8H dozer because the economics worked better than full shoe replacement.
  
• Another mechanic noted he’s never personally seen a weld-on grouser solution on his machines, preferring other repair options.
  

Material & Heat Treatment Options
4N offers both heat-treated and non-heat-treated grouser bars, depending on the customer's needs:

• Heat-treated bars are harder and more wear-resistant, ideal for harsher environments.
  
• Standard bars are suitable for less aggressive use or when cost is a key concern.
  

Real‑World Insight
Mechanics and operators who have used 4N bars say they’ve “always used 4N” when doing re-grouser work.  One user’s experience: on a large dozer, re‑grousering cost them under a tenth of what full track shoes would have cost — a big win for maintenance budgets.
Related Products
Here are some typical alternatives or related undercarriage parts:

• 4N Section 820 Grouser Bar: Smaller bar for compact or mini machines.
  
• 4N Section 840 Grouser Bar: One of the most widely used bar sizes for mid‑sized dozers.
  
• 4N Section 850 Grouser Bar (1B): Taller bar for larger track shoes.
  
• Caterpillar 20″ Shoe Grouser Bar 6Y6291: OEM-style grouser bar used on certain Cat machines.
  

Best Practices for Use

• Match the section of the bar to your machine’s track shoe size and type.
  
• When welding on bars, follow 4N’s recommended welding specs (preheat, weld type, etc.) to avoid damaging the track shoes.
  
• Check after welding: confirm that the new grouser height is not excessively above the original.
  
• Grease or inspect the undercarriage regularly to ensure the added bars are not causing abnormal wear or stress.
  

Conclusion
4N Corporation’s grouser bars are a proven, cost-effective solution for restoring traction and extending the life of tracked machine undercarriage components. By understanding the different sections (820, 840, 850, 870, 890) and choosing based on machine size and application, operators can save money and reduce downtime. While careful consideration is required for welding and compatibility, many users find that re-grousering is a superior alternative to full shoe replacement.