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Writer's pictureRALPH COPE
Aug 176 min read

Steel Tracked Excavators: A Deep Dive into the Bottom and Top Rollers

Steel tracked excavators are among the most important machines on any construction, demolition, or mining site. The ability to move massive amounts of earth or debris while providing precise handling and powerful digging makes these machines indispensable. However, the success of these machines depends on more than just the power of their engines or the efficiency of their hydraulic systems. The undercarriage—specifically the steel tracks, rollers, and other components—plays a vital role in their operation.


One of the key components in the undercarriage are the bottom and top rollers, also known as track rollers and carrier rollers, respectively. These rollers are essential to ensure smooth operation, even distribution of weight, and prolonged lifespan of the tracks and the machine itself. This blog will explore the function of these rollers, their composition, common issues that lead to damage, how to identify when they are failing, replacement guidelines, and the benefits of choosing used rollers from Vikfin.


The Function of Bottom and Top Rollers in Excavators

Bottom Rollers (Track Rollers)

Bottom rollers are positioned along the lower part of the undercarriage and are responsible for supporting the weight of the excavator as it moves. Their primary function is to transfer the machine’s weight from the upper structure down to the tracks and onto the ground. The bottom rollers guide the tracks, keeping them aligned, and ensure smooth movement of the excavator.


Since bottom rollers bear the full weight of the machine while in motion, they are subject to immense pressure and constant wear. In heavy-use environments, such as construction or mining sites, these rollers are constantly exposed to rough terrains, dirt, and debris. Consequently, they are prone to significant wear and tear over time.


Top Rollers (Carrier Rollers)

The top rollers, or carrier rollers, are mounted on the upper part of the excavator’s undercarriage. Unlike the bottom rollers, the top rollers do not bear the weight of the machine directly. Instead, they support the weight of the upper part of the track as it moves along the top of the undercarriage, preventing the tracks from sagging or loosening.

Top rollers help ensure that the tracks maintain tension, stay in place, and operate efficiently. By preventing sagging, these rollers extend the lifespan of the tracks and enhance the overall maneuverability of the excavator.


What Are Excavator Rollers Made Of?

Both bottom and top rollers are made from high-strength materials to withstand extreme conditions. Typically, the rollers are composed of the following components:

  • Roller Shell: This is the main body of the roller, usually made from forged or cast steel. The roller shell is designed to be durable and resistant to wear and impact.

  • Bushings and Bearings: Inside the roller shell, bushings and bearings are installed to reduce friction and ensure smooth rotation. These components are usually made of hardened steel or other heat-treated materials to handle the high stresses of operation.

  • Seals: Rollers are also equipped with seals to keep dirt, moisture, and other contaminants out of the bearings and bushings. The seals are usually made from synthetic rubber or other high-quality materials that can resist deterioration in harsh environments.

  • Axle or Shaft: The roller is mounted on an axle or shaft, which holds the roller in place and allows it to rotate as the excavator moves. This axle is also typically made from heat-treated steel for durability.


Common Damage to Excavator Rollers

Despite their rugged design, bottom and top rollers can still sustain damage over time. Here are some of the most common forms of damage:

  1. Wear and Tear: Continuous movement over rough terrains causes surface wear on the roller shell. This is the most common type of damage and usually results from friction between the rollers and the steel tracks.

  2. Cracking: Rollers may crack if they are subjected to repeated heavy impact, such as when the excavator works on rocky surfaces. Cracks can form in the roller shell, reducing its strength and leading to failure.

  3. Corrosion: In wet or muddy environments, water and moisture can seep past worn seals and cause corrosion inside the roller. Rusted bearings or bushings can seize up, preventing the roller from rotating freely.

  4. Bent or Damaged Axles: Axles can become bent or damaged if the excavator operates on uneven surfaces, particularly if the machine runs over large rocks or obstacles. This can cause the roller to wobble or misalign.

  5. Seal Failure: Seals are vital for keeping contaminants out of the roller’s internal components. If a seal fails, dirt, water, and debris can enter the roller and damage the bearings and bushings, leading to premature wear or total failure.


How to Know When Excavator Rollers Are Failing

Recognizing the signs of roller failure early on can prevent costly repairs and minimize downtime. Here are some key indicators that your excavator’s rollers may be failing:

  1. Unusual Noises: Grinding, squeaking, or clunking sounds coming from the undercarriage can be a sign that the rollers are not rotating smoothly or that their bearings have failed.

  2. Increased Friction: If the excavator is not moving as smoothly as it should or if you notice increased resistance while operating, the rollers may be worn or seized.

  3. Track Misalignment: Damaged rollers can cause the tracks to become misaligned. If the tracks appear to be riding unevenly on the undercarriage, it may be due to roller failure.

  4. Excessive Vibration: A failing roller can cause increased vibration in the machine, particularly when moving over rough terrain. This may indicate that the roller is not rotating properly or is unevenly worn.

  5. Visual Damage: Regular inspections of the undercarriage may reveal visible cracks, dents, or other damage to the rollers. Checking the seals for wear and ensuring the rollers are rotating freely can help identify potential problems early.


How to Replace Excavator Rollers

Replacing bottom and top rollers is a necessary part of maintaining an excavator’s undercarriage. Here is a step-by-step guide to the replacement process:

  1. Raise the Machine: Before replacing the rollers, the excavator needs to be raised off the ground. This can be done using a hydraulic jack or other lifting equipment.

  2. Remove the Track: The steel track must be removed to access the rollers. This involves loosening the track tension and carefully removing the track links.

  3. Remove the Old Rollers: Once the track is off, the old rollers can be unbolted and removed from the undercarriage. Make sure to check for any signs of damage on the mounting brackets or axles.

  4. Install the New Rollers: Position the new rollers on the mounting brackets and secure them with bolts. Make sure the rollers are properly aligned to ensure smooth operation.

  5. Reinstall the Track: After the new rollers are in place, reinstall the steel track by carefully positioning the links over the bottom rollers and top rollers. Tighten the track tension according to the manufacturer’s specifications.

  6. Test the Machine: Once the rollers and track are in place, test the machine to ensure smooth operation. Check for any unusual noises, vibrations, or signs of misalignment.


10 Reasons Why Clients Should Consider Used Rollers from Vikfin

Now that we’ve covered the basics of roller functionality, damage, and replacement, let’s look at why buying used rollers from Vikfin could be a smart decision:

  1. Cost Savings: Used rollers from Vikfin are a fraction of the price of new ones, offering a cost-effective solution without compromising on quality.

  2. High Quality: Vikfin carefully inspects and refurbishes all used rollers to ensure they meet OEM standards, providing reliable performance at a lower cost.

  3. Availability: With a wide range of used rollers in stock, Vikfin can quickly supply the parts you need, reducing downtime and keeping your machines running.

  4. Sustainability: Choosing used parts is an environmentally friendly choice. By opting for refurbished rollers, you contribute to reducing waste and promoting sustainability.

  5. Expertise: Vikfin’s team of experts ensures that all parts are in top condition, and they can help you choose the best rollers for your specific machine and operating conditions.

  6. Warranty Options: Vikfin offers warranties on many of their used rollers, providing peace of mind and added protection for your investment.

  7. Immediate Delivery: With a well-organized inventory system, Vikfin ensures fast delivery times, so you can get your machine back to work quickly.

  8. Custom Solutions: Vikfin offers custom refurbishment services to meet specific needs, ensuring the rollers are tailored to your machine’s requirements.

  9. Trusted Supplier: With a reputation for quality and customer service, Vikfin is a trusted name in the industry, providing reliable solutions for earthmoving machinery.

  10. Minimize Downtime: By opting for used rollers from Vikfin, you minimize the time your machine is out of commission, as their refurbished parts are readily available and quickly installed.


Conclusion

Bottom and top rollers are critical components of an excavator’s undercarriage, responsible for supporting the machine’s weight and ensuring smooth operation. While these rollers are built to withstand tough conditions, they can still suffer from wear, cracking, corrosion, and other forms of damage over time. Regular maintenance and timely replacement are essential for minimizing downtime and ensuring the machine’s longevity.


When it’s time to replace your excavator’s rollers, consider the cost-effective and reliable option of choosing used parts from Vikfin. With their commitment to quality, sustainability, and customer service, Vikfin provides the right solutions to keep your machine running efficiently for years to come.



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