What caster material offers the best shock absorption?

High-elasticity rubber (natural/synthetic, such as EPDM)
Features: High resilience (Shore hardness 50A-80A), wide temperature range (-40°C-120°C), quiet (≤55dB).
Applications: Precision instruments (medical equipment), transport of fragile items, outdoor light loads (grass/pavement).
Advantages: ★★★★★ Best shock absorption.
Limitations: Medium to low loads (≤200kg/wheel), average wear resistance.

Soft polyurethane (PU)
Features: Adjustable elasticity (60A-75A), wear and oil resistance, tear resistance.
Applications: Medium-load equipment (electronics/food transport), mixed flooring (frequent indoor and outdoor use).
Advantages: ★★★★☆ Excellent shock absorption, strong load capacity (≤300kg/wheel).
Limitations: Slightly reduced elasticity at low temperatures (requires a cold-resistant formula below -20°C), too soft and prone to collapse.

Pneumatic Tires
Features: Air pressure adjustment, elasticity, large deformation cushioning, and all-terrain grip.
Applications: Outdoor heavy-duty applications (construction sites/camping), and severe bumps on unpaved roads.
Advantages: ★★★★☆ Excellent high-impact shock absorption.
Limitations: Requires regular inflation and maintenance, and is relatively heavy.

Foam (Rubber/PU)
Features: Ultra-soft (40A-60A), porous energy absorption, extremely quiet, and lightweight.
Applications: Ultra-precision equipment (semiconductors), quiet environments (hospitals/libraries), and soft surfaces.
Advantages: ★★★★☆ Top-notch low-frequency shock absorption.
Limitations: Low load capacity (≤100kg/wheel), prone to permanent deformation, and should be avoided on rough surfaces.

Selection Principles:

Vibration Intensity: Mild Vibration → Soft PU; Moderate Vibration → Rubber; Severe Bumps → Pneumatic Tires (Low Pressure).

Equipment Sensitivity: Extremely Sensitive → Foam/PU; Moderately Sensitive → Rubber; General Needs → PU.

Load Requirements: Light load (≤100kg) → Foam/Rubber; Medium load (100-300kg) → PU/Rubber; Heavy load (>300kg) → Pneumatic tire/Reinforced rubber.

Summary: Rubber offers the best overall shock absorption, PU offers balanced durability, pneumatic tires are suitable for heavy-duty outdoor use, and foam material meets the requirements for ultra-quiet precision applications. Match the material based on vibration intensity, equipment sensitivity, and load capacity.