| How gear tooth counts were reverse-engineered | |||||||||
| Up: Table of Contents | Final results for this hub | ||||||||
| SRAM I-Motion 9 calculations (incorrect based on later tooth counts, but interesting. | |||||||||
| Number of gear teeth | Drive path | Ratios | |||||||
| Shifter Position | Sun Gear 1 | Pinion meshing with sun [1] | Pinion meshing with ring | Ring gear | 1=R to P, 2=Direct, 3=P to R | Drive ratio as fraction[2] | Drive ratio | from bro- chure | Ratio incre- ment |
| 1 | 36 | 13.03318 | 22 | 72 | 1 | 250/461 | 0.542 | 0.542 | |
| 2 | 30 | 15.00273 | 22 | 72 | 1 | 509/820 | 0.621 | 0.621 | 1.146 |
| 3 | 27 | 22 | 22 | 72 | 1 | 8/11 | 0.727 | 0.727 | 1.171 |
| 4 | 18 | 31.97674 | 22 | 72 | 1 | 250/293 | 0.853 | 0.853 | 1.173 |
| 5 | 18 | 31.97674 | 22 | 72 | 2 | 1 | 1.000 | 1.000 | 1.172 |
| 6 | 18 | 31.97674 | 22 | 72 | 3 | 1 43/250 | 1.172 | 1.172 | 1.172 |
| 7 | 27 | 22 | 22 | 72 | 3 | 1 3/8 | 1.375 | 1.375 | 1.173 |
| 8 | 30 | 15.00273 | 22 | 72 | 3 | 1 311/509 | 1.611 | 1.611 | 1.172 |
| 9 | 36 | 13.03318 | 22 | 72 | 3 | 1 211/250 | 1.844 | 1.844 | 1.145 |