Idlers play an important role in machinery that transports materials through belts, chains, or other conveyance systems. Properly engineered idlers ensure smooth, efficient operation while lowering operating costs and downtime.
What Is An Idler From Excavator Parts?

An idler is a rotating wheel or roller that supports a belt, chain or track in material handling systems. Common types of idlers include:
• Live idlers – Rotate freely with the conveyance. Used to provide tension and alignment.
• Fixed idlers – Remain stationary while the belt or chain moves over them. Provide guidance and support.
• Return idlers – Guide the belt or chain back to the head pulley in a conveying system.
• Front idlers – Direct the belt or chain at the infeed point in conveyors.
Idlers are usually made of steel, aluminum or polymer and have sealed bearings or bushings for long life.
About Excavator Undercarriage – Idler Functions
Idlers serve multiple purposes in material handling systems:
- They transmit load – Idlers carry the weight of the conveyed material.
- They provide guidance – Idlers keep the belt or chain centered and aligned.
- They maintain tension – Live idlers maintain proper tension in the conveyance.
- They reduce wear – Idlers lower friction and distribute load for reduced wear on belts and chains.
- They dampen vibration – Idlers help absorb vibration for smoother operation.
- They minimize energy loss – Smooth-turning idlers reduce energy loss from friction.
Factors To Consider When Choosing Idlers From Idler Manufacturer
When selecting replacement idlers for your conveyor or track system, consider:
• Load rating – The idler must be rated to support the weight of conveyed material.
• Size – Outer diameter, width and bore must match your needs.
• Material – Steel, aluminum or polymer construction for durability.
• Bearings/bushings – Sealed bearings provide longer life and lower maintenance.
• Auxiliary functions – Special features like roller detect, belt cleaners, etc.
• Warranty – A longer warranty indicates better-quality idlers designed for your application.