⚙️ BMW SMG II / SMG III Sequential Manual Gearbox
BMW's Sequential M Gearbox (SMG) is an electro-hydraulically actuated 6-speed that provides paddle-shift gear changes in approximately 80 ms while retaining the mechanical efficiency of a conventional manual gearbox (unlike a torque-converter automatic). The E46 M3 used SMG II; the E60 M5 used SMG III (7-speed). Both systems use the same operating principle — hydraulic actuators replacing the manual clutch pedal and gear lever — giving M-division engineers the ability to offer the same total-loss mechanical efficiency of a manual with sub-100ms shift times previously reserved for racing.
Transmission
Technical Specifications
| Type | Sequential Electro-Hydraulic 6-Speed (SMG II) / 7-Speed (SMG III) |
|---|---|
| Shift Time | 80 ms (SMG II) / 65 ms (SMG III) |
| Gears | 6 (E46 M3) / 7 (E60 M5) |
| Actuation | Electro-hydraulic (single clutch) |
| Drive By Wire | Yes (integrated with M Power management) |
| Clutch | Single dry-plate (same as manual) |
| Manufacturer | BMW AG / GKN / Drexler, Munich, Germany |
| Msrp | $3,500–$7,500 (rebuilt) |