Rubber Shore Hardness Explained: A Complete Guide
Last updated: March 2026
Quick Answer
Shore hardness measures rubber firmness on a 0-100 scale. Shore A is used for flexible rubbers (20A = soft sponge, 70A = car tyre, 90A = shopping trolley wheel). Higher number = harder rubber.
The Shore Hardness Scale
Shore Hardness Examples
- 20-30 Shore A: Gel insoles, soft sponge rubber
- 40 Shore A: Rubber bands, soft seals
- 50-60 Shore A: Door seals, weatherstripping
- 60-70 Shore A: Car tyres, standard gaskets
- 70-80 Shore A: Shoe soles, firm seals
- 80-90 Shore A: Shopping trolley wheels, hard gaskets
- 90-95 Shore A: Solid wheels, hard protective strips
Which Shore Hardness Do I Need?
| Application | Recommended Shore A | Why |
|---|---|---|
| Door/window seals | 50-60A | Soft enough to compress, firm enough to seal |
| Gaskets | 60-70A | Compresses under bolt pressure |
| Vibration dampening | 40-50A | Absorbs vibration energy |
| Impact protection | 50-60A | Cushions without bottoming out |
| Wear strips | 70-80A | Resists abrasion |
| Load bearing pads | 80-90A | Supports weight without excessive compression |
Frequently Asked Questions
What does Shore A mean?
Shore A is a durometer scale for measuring the hardness of flexible materials like rubber. It uses a spring-loaded pin that measures resistance to indentation. Shore D is used for harder plastics.
How do I measure Shore hardness?
Use a Shore A durometer - a handheld device with a pointed indenter. Press firmly against the rubber surface and read the dial. Professional testing requires calibrated equipment and specific test conditions.
Does hardness affect temperature resistance?
Hardness and temperature range are independent properties. A 40A EPDM and 80A EPDM can have the same temperature range. Material chemistry determines temperature performance, not hardness.
Can I get custom hardness rubber?
Yes. Rubber compounds can be formulated to specific hardness requirements. Standard increments are 5 Shore A points (40A, 45A, 50A, etc.). Contact us for custom hardness requirements.
Need help choosing the right hardness? Contact our technical team →