The PAX index was developed by Rick Ruth and reflects study of results from well over 500 nationwide Solo events. The below information is sourced from the official PAX webpage.
| Category | Class | Multiplier (2012) | Multiplier (2011) | Difference |
|---|---|---|---|---|
| Stock | A Stock | 0.844 | 0.841 | 0.003 |
| Stock | B Stock | 0.843 | 0.839 | 0.004 |
| Stock | C Stock | 0.833 | 0.833 | 0 |
| Stock | D Stock | 0.821 | 0.817 | 0.004 |
| Stock | E Stock | 0.828 | 0.825 | 0.003 |
| Stock | F Stock | 0.825 | 0.827 | -0.002 |
| Stock | G Stock | 0.814 | 0.809 | 0.005 |
| Stock | H Stock | 0.799 | 0.791 | 0.008 |
| Stock | Super Stock | 0.858 | 0.857 | 0.001 |
| Street Touring | Street Touring Compact | 0.820 | 0 | |
| Street Touring | Street Touring R | 0.835 | 0.836 | -0.001 |
| Street Touring | Street Touring Sport | 0.827 | 0.823 | 0.004 |
| Street Touring | Street Touring Ultra | 0.841 | 0.838 | 0.003 |
| Street Touring | Street Touring Xtreme | 0.822 | 0.824 | -0.002 |
| Street Touring | Street Touring FWD | 0.794 | 0 | |
| Street Prepared | A Street Prepared | 0.863 | 0.862 | 0.001 |
| Street Prepared | B Street Prepared | 0.859 | 0.859 | 0 |
| Street Prepared | C Street Prepared | 0.857 | 0.858 | -0.001 |
| Street Prepared | D Street Prepared | 0.851 | 0.844 | 0.007 |
| Street Prepared | E Street Prepared | 0.848 | 0.846 | 0.002 |
| Street Prepared | F Street Prepared | 0.838 | 0.835 | 0.003 |
| Street Prepared | Super Street Prepared | 0.865 | 0 | |
| Street Modified | Street Modified | 0.866 | 0.869 | -0.003 |
| Street Modified | Street Modified FWD | 0.852 | 0.855 | -0.003 |
| Street Modified | Super Street Modified | 0.879 | 0.875 | 0.004 |
| Prepared | B Prepared | 0.873 | 0.870 | 0.003 |
| Prepared | C Prepared | 0.860 | 0.860 | 0 |
| Prepared | D Prepared | 0.868 | 0.867 | 0.001 |
| Prepared | E Prepared | 0.870 | 0.863 | 0.007 |
| Prepared | F Prepared | 0.875 | 0.872 | 0.003 |
| Prepared | G Prepared | 0.850 | 0.837 | 0.013 |
| Prepared | X Prepared | 0.898 | 0.887 | 0.011 |
| Modified | A Modified | 1.000 | 1.000 | 0 |
| Modified | B Modified | 0.960 | 0.958 | 0.002 |
| Modified | C Modified | 0.906 | 0.906 | 0 |
| Modified | D Modified | 0.915 | 0.905 | 0.01 |
| Modified | E Modified | 0.928 | 0.910 | 0.018 |
| Modified | F Modified | 0.913 | 0.904 | 0.009 |
| Modified | Kart Modified | 0.952 | 0 | |
| Formula | Formula SAE | 0.989 | 0.981 | 0.008 |
| Formula | Formula Junior A | 0.876 | 0 | |
| Formula | Formula Junior B | 0.834 | 0 | |
| Formula | Formula Junior C | 0.747 | 0 | |
| Category | Class | Multiplier (2012) | Multiplier (2011) | Difference |
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