Rubber hardness, commonly measured on the Shore A scale, plays a decisive role in the overall performance and stability of anti-slip pads used with automotive and industrial jacks. Different hardness levels influence deformation resistance, friction behavior, load distribution, and long-term reliability during lifting operations.
Influence on Load-Bearing and Deformation
Rubber with higher hardness provides greater resistance to compression. When a jack applies concentrated load, a hard pad maintains its geometric shape more effectively, preventing excessive sinking and reducing the risk of tilt or lateral shift. However, if the hardness is too high, the pad may lose its ability to conform to uneven ground surfaces, which can negatively affect overall stability.
Influence on Anti-Slip Performance
Anti-slip performance is strongly related to the real contact area between the pad and the jack base. Moderate hardness allows the pad surface to slightly deform, increasing friction and grip. Softer pads offer excellent contact but may compress too much under heavy loads, reducing stability. Conversely, overly hard pads provide limited surface friction, especially on smooth metal surfaces.
Influence on Shock Absorption
One key purpose of a rubber pad is to absorb micro-vibrations and prevent sudden load shifts. Medium-hardness rubber typically delivers the best balance between stiffness and resilience. Softer rubber absorbs shocks well but risks structural fatigue; harder rubber transmits more vibration, potentially affecting jack safety.
Influence on Long-Term Durability
Rubber hardness also correlates with abrasion resistance and structural integrity. Harder rubber pads tend to have higher wear resistance, especially under repeated jack placement. Softer materials may suffer from surface tearing or permanent deformation over time. The ideal hardness selection depends on the load capacity of the jack, working environment, and frequency of use.
Recommended Hardness Range
For most vehicle jacks and industrial lifting tools, a Shore A hardness between 65 and 80 is widely considered optimal. This range ensures sufficient deformation resistance, effective friction, and long service life without compromising stability.
References
ASTM D2240 – Standard Test Method for Rubber Property—Durometer Hardness.
Gent, A. N. Engineering with Rubber: How to Design Rubber Components. Hanser Publishers.
Smith, J. & Lee, K. (2019). “Mechanical Behavior of Elastomeric Pads under Compressive Load.” Journal of Materials Engineering.
ISO 7619-1 – Rubber, Vulcanized or Thermoplastic — Determination of Indentation Hardness.
