Rubber Hardness Explained | Shore A Durometer Guide UK
Understanding Rubber Hardness: Shore A Guide
Shore hardness determines how firm or soft rubber feels and performs. This guide explains the Shore A scale and helps you select the right hardness for your application.
What is Shore Hardness?
Shore hardness measures a material's resistance to indentation using a durometer. The Shore A scale (0-100) is used for flexible rubbers and elastomers. Higher numbers indicate harder, more rigid materials.
Shore A Scale Explained
| Shore A | Feel | Comparable To | Flooring Applications |
|---|---|---|---|
| 10-20 | Very soft, gel-like | Rubber band | Specialised cushioning |
| 20-40 | Soft, spongy | Pencil eraser | Anti-fatigue mats, comfort flooring |
| 40-60 | Medium firm | Car tyre rubber | Gym flooring, playground surfaces |
| 60-70 | Firm | Shoe heel | Industrial flooring, walkways |
| 70-80 | Hard | Shopping trolley wheel | Heavy traffic areas |
| 80-90 | Very hard | Hard hat material | Machinery bases, extreme durability |
Selecting the Right Hardness
Anti-Fatigue Mats: 20-40 Shore A
Softer rubber provides cushioning that reduces leg fatigue for standing workers. The material compresses under body weight, encouraging micro-movements that improve circulation.
Gym Flooring: 40-60 Shore A
Medium firmness balances comfort with stability. Provides enough cushioning for dropped weights and impact but firm enough for stable lifting and exercise.
Industrial Flooring: 60-80 Shore A
Firmer rubber withstands heavy loads, forklift traffic, and continuous use. Less cushioning but maximum durability and longevity.
Testing Shore Hardness
Shore hardness is tested using a durometer—a device that measures indentation depth under a specified force. The test is standardised under ASTM D2240 and ISO 48-4.
Professional suppliers like Slip-Not test rubber to specified hardness ranges and can provide durometer readings on request.
Hardness vs Other Properties
Hardness affects other properties:
- Softer rubber: Better cushioning, more prone to indentation, lower abrasion resistance
- Harder rubber: More durable, better load-bearing, less comfortable underfoot
