| N. drop | Stiffness | Preload level | |||
| 0.097 | 0.124 | 0.206 | 0.344 | ||
| 1 | K1 | 10.6 | 13.3 | 17.3 | 19.7 |
| 2 | K2 | 18.1 | 20.8 | 23.5 | 26.1 |
| 3 | K3 | 21.2 | 21.1 | 23.5 | 25.7 |
| 4 | K4 | 21.3 | 22.3 | 23.2 | 25.4 |
| 5 | K5 | 24.1 | 23.2 | 23.3 | 26.7 |