Superior Tire & Rubber
Jerrod Ossa, Aftermarket Sales Manager – AgriTraxx® Undercarriage Wheels

Tracked Tractors are powerful, ultra-capable machines that help producers maintain and harvest their crops. As one might not be too familiar with some of the components that help these machines operate, I am going to highlight the undercarriage components (specifically the Mid-Rollers, Idlers, and Drive Wheels) and provide tips on how to properly maintain them.

Mid-Rollers
Mid-Rollers are the smaller wheels that make up the undercarriage. These wheels play a vital role in distributing weight evenly across the track. Their small size and the big role they play means they will wear out faster than drive wheels or idlers – and that’s OK, because they are far cheaper and easier to replace than drives or idlers. Depending on what size tracks a producer needs for their operation, midrollers can vary in outer diameter (OD) size and width. Mid-Rollers commonly have an OD of 14 inches and can go up to 17 inches. The width of the midroller varies depending on the track size. For those with narrower row crop machines (typically using 18-inch-wide rubber tracks) the width of the mid-roller is on average 5 inches. However, those with wider tracks (24” or 36”) the common width of the midroller is anywhere between 8 inches up to 10.5 inches. Wider mid-rollers tend to handle heat a little bit better than narrow mid-rollers simply due to the larger surface area which allows for more airflow to cool the wheel during operation. But the heat will build up regardless of size, so managing the heat is the #1 priority for longer lasting mid-rollers.

Not all tractors are created equal, and neither are their mid-rollers. Agco and John Deere machines normally have bolt-on style mid-rollers meaning the bearings and seals are on the axle of the tractor like your car or truck. Bolt-on mid-rollers are much cheaper to make, much cheaper to buy, easier to install, and are prime candidates for remanufacturing/core exchange rebate programs. Alternatively, Case IH machines historically use hub-bearing style mid-rollers, meaning that the bearing and seals are a part of the wheel. When hub-bearing style mid-rollers need replaced, so do the bearings, seals, etc. making for a longer install time which adds to maintenance costs. Hub-style mid-rollers are much more expensive and more difficult to remanufacture. Monthly checks of oil levels within the seal of the bearings are required to ensure that the wheel will continue to operate properly. I believe hub-style mid-rollers are slowly being transitioned to bolt-on style mid-rollers at all OEMs for obvious reasons, including Case IH. Either way, when it comes time to replace mid-rollers, whatever the reason, replace them in pairs – both on the inner and outer side of the track. This ensures even wear on just about every component of the undercarriage.

         

Hub-bearing style midroller                  Bolt-on style midroller

 

Idlers
Idler wheels are larger than mid-rollers with most ODs ranging from 24 to 27 inches. A select few can be as large as 35 inches. Idlers are typically located in front of a tracked machine (mostly found on friction drive systems), though triangular RT systems use 2 idlers located in both front and back (mostly found on Positive Drive systems). The Idler wheel’s primary purpose is guiding the rubber track for optimal alignment and maintaining the proper tension in the track. These wheels are normally less maintenance and require fewer replacements than mid-rollers because they are not as load bearing and do not generate as much heat. Nonetheless, a good practice is to check the OD of the idler every so often to ensure that no chunking of the material is visible. This can be done in conjunction with routine track tension checks – a loose track can cause havoc on just about every part of the RT system very quickly. Finally, albeit rarer, check for stress cracks on the inner diameter (ID) of the idler wheel. Over the lifespan of the idler wheel, small cracks can start to form near bolt holes. These are simple tack weld fixes if caught early enough. Like mid-rollers, the width of the track determines the width of the idler. Thankfully, the majority of idler wheels are bolt-ons rather than hub-bearing style, which makes replacements more user friendly.

 

Drive Wheels
Drive wheels are the largest wheels on the undercarriage of a tracked tractor. On average, these wheels are anywhere between 40 inches up to 61 inches. The primary purpose of the drive wheels is to propel the vehicle forward or backwards. There are two different drive systems that a tracked tractor uses: friction-drive or positive drive system. (See “Friction Drive VS Positive Drive AG Track Systems” on agtracktalk.com for an excellent overview of the pros & cons of friction drives and positive drives.) Like idlers, drive wheels are fairly low maintenance and require even fewer replacements, which is good because they are the least fun to replace. However, they are not indestructible and are also susceptible to stress cracking around bolt holes. Even though they wear much slower than idlers & mid-rollers, routinely checking for missing tread material (chunking) or excessive wear on the OD of the tire is excellent preventative maintenance. I recommend, at minimum, conducting a once-a-month routine inspection because the drive wheels are the most important, most expensive, and hardest to replace wheels on the entire undercarriage.

Conclusion
Tracked equipment has its challenges with things like additional components and more tedious maintenance routines, but challenges become less challenging with experience. Tracked systems work amazingly well at reducing burden in the field typically found in pneumatic tire tractors. If you’re unfamiliar with tracked undercarriage systems and found this article while researching them, I hope this provided an entry level of detail on the various parts and issues to look out for when conducting preventative maintenance. For those who already have tracked equipment and were hoping to learn something new, we hope you did. At Superior Tire, we have decades of experience with tracked farm equipment and love talking shop – reach out to us at any time with a question!

 

 

Camso
David Graden: Operational Market Manager – Agriculture

Camso Ag Tracks & Systems, by Michelin, produces several different types of Ag Track Systems:  Friction Drive System, Positive Drive System & Non-Powered System. Each of these are made up of the same major components but arranged in a slightly different manner depending upon the machine manufacturer’s design needs.

In each of the images below, you will see the following major components, however the lubrication schedule for Camso Ag track systems may vary depending on machine, application and/or drive type. This is a general overview. It’s important to refer to the specific maintenance manual for your track system to ensure you follow the correct procedures and intervals. Regular maintenance helps in prolonging the life of the components and ensures optimal performance.

 

 

Drive Wheel

  • Purpose – responsible for transferring power from the tractor to the track system, enabling movement and traction. It engages with the track to propel the vehicle forward and backward
  • Lubrication Schedule
    • Positive Drive – Lubricate the drive wheel bearings every 250 hours of operation
    • Friction Drive – Lubricate the drive wheel bearings every 250 hours of operation
    • Non-powered – Since the drive wheel in a non-powered system doesn’t transmit power, it typically requires less frequent lubrication. Lubricate the bearings every 500 hours of operation

Midroller

  • Purpose – supports the track and helps distribute the weight of the vehicle evenly across the track system. This reduces soil compaction and improves stability and ride comfort.
  • Lubrication Schedule
    • Positive Drive – Lubricate the midroller bearings every 250 hours of operation
    • Friction Drive – Lubricate the midroller bearings every 250 hours of operation
    • Non-powered – Lubricate the midroller bearings every 500 hours of operation

Idler Wheel

  • Purpose – guides the track and maintains proper tension. It ensures the track stays aligned and functions smoothly, preventing derailment and excessive wear.
  • Lubrication Schedule
    • Positive Drive – Lubricate the idler wheel bearings every 250 hours of operation
    • Friction Drive – Lubricate the idler wheel bearings every 250 hours of operation
    • Non-powered – Lubricate the idler wheel bearings every 500 hours of operation

Tension Cylinder

  • Purpose – adjusts the tension of the track system to maintain optimal performance. Proper tension is crucial for preventing track slippage and ensuring efficient power transfer.
  • Lubrication Schedule
    • Positive Drive – Check and lubricate the tension cylinder as needed, typically during regular maintenance checks
    • Friction Drive – Check and lubricate the tension cylinder as needed, typically during regular maintenance checks
    • Non-powered – Check and lubricate the tension cylinder as needed, typically during regular maintenance checks

To find more information about our Service Conditions and Warranty Guidelines, please visit the link: Camso Ag Service Conditions and Warranty_Guidelines

 

Trackman
Tom Feldmann, Chief Manager of Engineering Development

Understanding the names, functions, and maintenance schedules of each undercarriage component is essential to maximizing track performance and longevity in agricultural machinery. This guide outlines both Friction Drive and Positive Drive systems, including lubrication schedules and maintenance tips.

FRICTION DRIVE SYSTEMS

Key Components & Functions

Drive Wheel

  • Purpose: The drive wheel is typically rubber-coated to create the required friction that enables vehicle movement.
  • Lubrication: Avoid getting petroleum-based products on rubber, as these can soften the material and lead to premature failure.
  • Maintenance Tips:
    • Replace the drive wheel if worn.
    • Remove any foreign materials to maintain optimal
    • Regularly inspect for wear and follow OEM replacement guidelines.
  • Alignment: Critical for track longevity. Check alignment routinely as per OEM procedures.
  • Additional Notes: Ice, frost, mud and/or ingested debris can affect performance damage system components.

Idler Wheel

  • Purpose: Primarily used to tension the track system and support the transition of the track over the bogie wheels.
  • Lubrication: Follow the OEM’s lubrication schedule. Avoid getting petroleum-based products on rubber, as these can soften the material and lead to premature failure.
  • Maintenance Tips:
    • Inspect rubber or polyurethane coating; replace if more than 1/3 of the width is missing.
    • Ensure idlers are properly elevated to reduce tread wear.
    • Use the correct track length. Tracks that are too long or too short can cause slippage, tensioning issues, or damage.
  • Alignment: Follow the same alignment procedure as the drive wheel.

Bogie Wheels (Mid-Rollers)

  • Types: Bearing Bore and Bolt-On. Most modern systems use Bolt-On for easier maintenance.
  • Purpose: Support most of the machine’s weight when roading or parked.
  • Lubrication: Same as the drive wheel. Check for leaks and ensure lubrication is sufficient.  Keep rubber elements free from oils and petroleum products.
  • Maintenance Tips:
    • Inspect daily before operation for proper lubrication.
    • Ensure rubber or polyurethane is present around the full wheel circumference.
    • Replace any bogie wheels with more than 1/3 of the surface width worn or missing.

Alignment: Consistent with other components in the system.

Mounts & Isolation Blocks

  • Purpose: These components help absorb road vibrations and conform to road curvature, improving ride quality and reducing stress on the machine.
  • Maintenance Tips: Regularly inspect and maintain according to OEM specifications.

New Track Conditioning

Before first use, rubber tracks must be pre-conditioned to prevent early wear and damage:

  • Preferred Method: Operate for at least 15 minutes in a field with loose soil.
  • Alternative Method:
    • Apply a layer of dirt, talc, graphite, or non-caustic particulate to all contact surfaces.
    • Drive forward to coat the system.
    • When roading, apply dirt every 30 minutes for the first few hours.
  • Break-In Period: Tracks continue conditioning for the first 150 hours of use.
  • Alignment: Critical for track longevity. Check alignment routinely as per OEM procedures. Misaligned tracks can become damaged and thereby reducing the track life

POSITIVE DRIVE SYSTEMS

Key Components & Functions

Drive Wheel

  • Purpose: A metal gear or cage-type wheel engages directly with the track’s lugs for movement.
  • Maintenance Tips:
    • Ensure the wheel is within OEM wear tolerances.
    • Replace if excessive wear is present to avoid vibration and lug damage.
    • Keep the system free from foreign debris.
  • Alignment: As with friction systems, proper alignment is essential to track life and performance.

Mounts & Isolation Blocks

  • Purpose: As in friction systems, these components reduce vibration and enhance road compliance.
  • Maintenance Tips: Inspect regularly and follow OEM replacement or adjustment guidance.

New Track Conditioning

  • Follow the same procedure outlined in the Friction Drive section above.

Final Thoughts

Proper care and maintenance of your undercarriage components—including daily inspections, lubrication, and alignment checks—will significantly improve the performance and life of your track system. Always refer to your OEM manuals for specific part tolerances, schedules, and procedures tailored to your equipment.

 

All information is provided in this blog solely to provoke thought. All deductions made from information on this site must be confirmed by Certified Ag Track Dealer before use. Ag Track Talk does not recommend anyone conduct track service work with exception of Certified Ag Track Dealer Professionals.