Product Details
The guide wheel of the Caterpillar E55 excavator is a precise and crucial chassis component. Its core is made of high-strength wear-resistant cast steel, and the key flange surface is quenched and hardened. It guides and restricts the track chain through precisely designed flanges and wheels, achieves low-resistance rotation through internal bearings/bushings and lubrication systems, and relies on an effective sealing system to resist external contamination. Its precise dimensions (such as the diameter of the shaft hole, the position of the installation hole, the width of the wheel, and the outer diameter) ensure a perfect match with the E55 chassis system. Regular lubrication maintenance and working condition inspection are the basis for maintaining its best performance and longest service life.
Caterpillar E55 Excavator Idler Wheel - Technical Data Sheet
1. Compatibility & Identification
Parameter | Specification |
Machine Model | Caterpillar E55 Mini Excavator (Verify sub-model & s/n via equipment PIN) |
OEM Part No. | 8Y-0721 (Primary reference; critical to confirm via physical idler or PIN) |
Aftermarket Ref. | ITR: GU1001 · Berco: 30500721 · Link-Belt: 3050-0721 |
Function | Guides upper track chain, maintains tension & alignment, absorbs operational shock |

2. Material & Construction
- Core Material: High-tensile cast steel (Grade ZG340-550, yield strength ≥550 MPa).
- Wheel Rim: Induction-hardened surface (HRC 55-60), wear depth ≥5 mm.
- Bearing System:
- Option A: Sealed needle roller bearings (DIN 5402).
- Option B: Bronze bushings (CuSn8P, oil-impregnated).
- Sealing: Dual-lip steel-case seals + Nitrile O-rings (IP68-rated, -30°C to 120°C).
- Lubrication: Central grease nipple (1/4" NPT), accepts lithium-complex grease (e.g., Cat GO-4).
3. Dimensional Specifications (mm)
Dimension | Value | Tolerance |
Outer Diameter (Rim) | 295 | ±0.5 |
Total Width (w/ flanges) | 118 | ±0.3 |
Rim Gauge Width | 98 | ±0.2 |
Bore Diameter (Shaft hole) | 70 | +0.02 / -0 |
Mounting Bolt Holes | 2 × Ø18 | H11 |
Bolt Circle Diameter (PCD) | 120 | ±0.1 |
Net Weight | 20.5 kg | - |
4. Performance & Durability
- Load Capacity:
- Static: 8,000 kg · Dynamic shock load: 15 kN (ISO 5683 compliant).
- Service Life:
- Standard conditions: 3,000–5,000 hrs.
- Severe conditions (rock/abrasives): ≤1,500 hrs (lubricate every 10 hrs).
- Operating Temp.: -40°C to +80°C (ambient).
5. Maintenance & Inspection
- Lubrication Interval:
- Normal: 50 hrs (150g grease) · Severe: 20 hrs.
- Wear Limits:
- Rim thickness wear >10% → Replace immediately.
- Flange height <15 mm → High derailment risk.
- Track Tension: Maintain 30–50 mm sag (mid-span between carriers).
6. OEM vs. Aftermarket Guidance
- Genuine CAT Identification:
- Laser-etched p/n
8Y-0721
+ CAT logo on casting. - Holographic anti-counterfeit label on packaging.
- Aftermarket Selection:
- Require material certification (hardness, impact test per ASTM E23).
- Prioritize ISO 9001-certified manufacturers (e.g., ITR, Berco).
- ⚠️ Risk Alert: Non-genuine idlers may cause:
- Premature seal failure → Bearing contamination → Track misalignment.
7. Technical References
- Installation: CAT SEBD0518-08 procedure.
- Torque Specs: Mounting bolts – 380 ±20 N·m (lubricate threads).
- Validation: Confirm compatibility via CAT SIS 2.0 using machine PIN.
For real-time inventory/pricing, provide equipment Product Identification Number (PIN) or physical idler measurements (bore, PCD, width).
Note:
Important note: When purchasing replacement parts, providing the exact model, serial number of the device or the part number on the old guide wheel is the only reliable way to ensure that you get a perfectly matched and reliable component. Dimensions and details may vary slightly due to manufacturing batches or different third-party suppliers.
