EX300 Excavator Top Roller Steel OEM Fit

The ​​EX300 top roller​​ (also known as ​​upper roller​​ or ​​carrier roller​​) is a key wear part in the undercarriage system of Hitachi EX300 excavators. It plays a vital role in supporting the track between the sprocket and idler, guiding track movement, and maintaining proper track tension—ensuring consistent machine stability and reducing premature wear on other undercarriage components (e.g., tracks, sprockets). Regular inspection and maintenance of the top roller are essential to minimize downtime and extend the life of the entire undercarriage system.

Our production involves rigorous quality-controlled processes:

• High-grade Material Selection: Components are crafted from premium materials for maximum durability
• Outer Race/Shell: High-carbon chromium bearing steel (SUJ2) for superior hardness and wear resistance
• Inner Roller/Spindle: Alloy steel (SCM440) engineered to withstand significant radial and axial loads
• Seals & Lubrication: Nitrile rubber (NBR) seals for oil resistance with lithium-based grease for long-term lubrication
• Quality Assurance: All materials undergo thorough inspection for chemical composition and mechanical properties using spectrometers and hardness testers