Product Overview

The Track Roller, also known as Bottom Roller or Lower Roller, is an important undercarriage component installed beneath the track frame of Kubota KX121 crawler excavators.

The roller carries the machine operating weight, supports the track chain and maintains proper crawler alignment during travelling and excavation operations.

For compact excavators like Kubota KX121, track rollers are exposed to:

• Continuous machine loading
• Uneven ground impact
• Soil and gravel abrasion
• Mud and water contamination
• Frequent travelling operations

A worn or damaged track roller may cause:

• Track chain misalignment
• Increased travelling vibration
• Abnormal track noise
• Uneven track wear
• Accelerated sprocket and idler wear
• Increased maintenance costs

Our Kubota KX121 track rollers are manufactured using professional undercarriage production technology to provide reliable aftermarket replacement solutions for equipment dealers, repair workshops and machine owners.

Key Features & Benefits

Wide Compatibility

Designed for:

• Kubota KX121
• Kubota KX121-2
• Kubota KX121-3

Reference OEM numbers:

• RD101-99900
• RD118-21700
• RD148-21700

Different production years may use different OEM references. Please confirm before purchase.

Heavy-Duty Alloy Steel Construction

Manufactured from:

40Mn2 Alloy Steel

Advantages:

• High structural strength
• Good impact resistance
• Excellent wear resistance
• Long service life

Advanced Heat Treatment

The roller tread surface is induction hardened.

Specification:

• Surface hardness: HRC 52-58
• Hardening depth: 5mm-10mm

Provides improved resistance against:

• Soil abrasion
• Gravel impact
• Daily operating wear

Reliable Floating Seal System

Equipped with:

• Heavy-duty floating oil seals
• Wear-resistant bushings
• Lifetime internal lubrication

Designed to prevent:

• Grease leakage
• Dust intrusion
• Water contamination

OEM-Style Direct Replacement

Manufactured with:

• Accurate roller dimensions
• Correct shaft specifications
• Standard mounting structure

Provides direct bolt-on replacement without modification when the correct model is selected.

Technical Specifications