Hitachi EX550/ZX650/JD550/JD600 Track Roller Group/Heavy duty excavator undercarriage components manufacture and supplier

Product Specifications

1. What is a Track Bottom Roller Group? (Definition and Function)

DPW Parts' Track Bottom Roller Group (often called a lower roller or simply a bottom roller) is an essential component of an excavator's undercarriage system. On large models like the Hitachi EX550 and Hitachi ZX650, these rollers bear the immense weight of the machine and facilitate the smooth movement of the track chain.

Primary Functions:

• Support Machine Weight: They are the primary contact points between the excavator's main structure and the track chain, supporting the majority of the machine's operational weight.

• Guide the Track Link: The flanges on the rollers keep the track chain aligned, preventing derailment during operation, especially on uneven terrain.

• Reduce Friction: Sealed and lubricated internal bearings allow the roller to rotate freely, reducing friction as the track moves over it, which minimizes power loss and wear.

• Distribute Load on Ground: They help distribute the machine's massive weight more evenly across the track shoe, improving stability and reducing ground pressure.

2. Key Features of Hitachi EX550/ZX650 Bottom Rollers

The bottom rollers for these 50-70 ton class excavators are built to extreme specifications to handle brutal working conditions.

• Robust Construction: Made from high-carbon, alloy steel forgings that are heat-treated for maximum hardness and wear resistance.

• Large Diameter and Width: Designed to handle the high load capacity and provide stability for these massive machines.

• Advanced Sealing System: Utilizes multi-labyrinth seals and high-performance grease to keep contaminants (abrasive dirt, mud, water) out and lubrication in, significantly extending service life.

• Precision Bearings: High-capacity tapered roller bearings or special spherical bearings are used to manage both radial and axial loads.

• Interchangeability: The bottom roller group for the Hitachi EX550 and ZX650 are often interchangeable or very similar, but it is CRUCIAL to always check your specific serial number before purchasing.

3. Common Problems and Signs of a Worn Bottom Roller

Ignoring roller maintenance leads to costly downtime and further damage to the undercarriage.

• Visible Flange Wear: Worn-down or sharp flanges can no longer properly guide the track, increasing the risk of derailment.

• Loss of Lubricant (Leaking Grease): Failed seals allow grease to escape and contaminants to enter, leading to rapid bearing failure. You'll see dirt stuck to grease around the seal.

• Irregular or Excessive Wear: Flat spots or concave wear on the roller surface indicate misalignment or lack of rotation ("flat spotting" from machine parking for long periods).

• Noise and Failure to Rotate: A seized roller won't turn. You'll hear grinding, squealing, or rumbling sounds from the undercarriage, and the track movement will become jerky.

• Increased Track Sag: Worn rollers cause increased friction, which stretches the track chain and increases sag, requiring frequent adjustment.

4. OEM vs. Aftermarket Replacement Rollers: Which is Best?

This is a critical decision that impacts cost, performance, and machine longevity.

• OEM (Original Equipment Manufacturer) Parts:

  • Pros: Guaranteed to meet Hitachi's exact specifications, perfect fit, highest quality materials and sealing technology, backed by a warranty.

  • Cons: Significantly higher purchase price.

• High-Quality Aftermarket Parts:

  • Pros: Can offer substantial cost savings (often 30-50% less than OEM). Reputable brands use materials and engineering that meet or sometimes exceed OEM standards.

  • Cons: Quality varies wildly between suppliers. Choosing a poorly made roller can lead to premature failure, causing more expense in the long run.

Recommendation: For critical components like rollers, choose a reputable aftermarket manufacturer with a proven track record, certified ISO quality controls, and who offers a solid warranty. "Value for money" is better than "lowest price."

5. How to Find and Buy high quality Hitachi EX550/ZX650 Bottom Rollers and spare parts?

Your search intent likely includes a local component. Here’s how to connect with suppliers.

• Search Terms to Use: Combine the part name with location and service intent:

  • Hitachi EX550/ZX650 bottom roller replacement near me

  • Quanzhou,Fujian,China Hitachi excavator undercarriage parts source manufacture&factory.

  • Buy ZX650 track roller group Australia from DPW parts 

  • Hitachi undercarriage parts supplier USA/UK

• What to Look for in a Local Supplier:

  • Inventory: Do they have the part in stock locally to minimize downtime?

  • Expertise: Do they specialize in undercarriage components for large excavators?

  • Services: Do they offer technical support, installation services, or undercarriage measurement?

  • Brands: Do they carry trusted OEM and premium aftermarket brands (e.g., ITR, Berco, Talon, DPW Parts,cqctrack)?

6. Installation and Maintenance Tips

• Always Replace in Sets: It is highly recommended to replace multiple rollers on the same side at once. Replacing just one worn roller can place uneven stress on the new one and the entire track system, accelerating wear.

• Professional Installation: The undercarriage is under immense tension. Installation should be performed by trained technicians using proper tools and safety procedures.

• Regular Cleaning: Keep the undercarriage, especially around rollers, free of packed mud and debris. This material acts as an abrasive and can damage seals.

• Proper Track Tension: Maintain the track tension according to the operator's manual. Over-tightening increases roller and sprocket wear; too loose increases the risk of derailment and causes excessive pounding on components.

Conclusion: Maximizing the Life of Your Investment

The Hitachi EX550/ZX650 Track Bottom Roller Group is a fundamental pillar of your machine's productivity. Proactive inspection, choosing quality replacement parts from a reputable supplier—whether OEM or premium aftermarket—and professional maintenance are not expenses; they are investments that prevent catastrophic downtime and protect the value of your heavy equipment.

Ready to find a reliable part? Search for local undercarriage specialists today and ensure your Hitachi excavator keeps moving efficiently.