| No | Type | Normal Ratio Range | Efficiency Range |
| 1 | Spur | 1:1 to 6:1 | 94-98% |
| 2 | Straight Bevel | 3:2 to 5:1 | 93-97% |
| 3 | Spiral Bevel | 3:2 to 4:1 | 95-99% |
| 4 | Worm | 5:1 to 75:1 | 50-90% |
| 5 | Hypoid | 10:1 to 200:1 | 80-95% |
| 6 | Helical | 3:2 to 10:1 | 94-98% |
| 7 | Cycloid | 10:1 to 100:1 | 75% to 85% |
References
http://www.meadinfo.org/2008/11/gear-efficiency-spur-helical-bevel-worm.html