| MODEL | NSU FOX 1949 - 1954 |
| Year | 1949 - 1954 |
| Engine Type | Single cylinder, OHC, 4 stroke |
| Displacement / Capacity | 98 cc (4 stroke); 123 cc 2 stroke from 1951 |
| Bore X Stroke | 50 x 50 mm |
| Compression Ratio | 6:1 |
| Cooling System | Air/Oil cooled |
| Max Power | Approx. 4.4 kW / 6 hp @ 6500 rpm |
| Max Torque | — |
| Ignition | — |
| Induction | — |
| Start System | Kick start |
| TRANSMISSION SPECS | |
| Lubrication | Oil pump |
| Gear Box | 3 Speed (4 Speed from 1950) |
| Clutch | — |
| Final Drive | Chain in oil bath |
| CHASSIS SPECS | |
| Frame | Pressed steel central clamping frame |
| Front Suspension | Coil springs with adjustable friction dampers |
| Rear Suspension | Short swingarm, central coil spring, adjustable friction dampers |
| Front Brakes | — |
| Rear Brakes | Internal shoe |
| DIMENSION SPECS | |
| Overall Length | 1910 mm / 75.2 in |
| Overall Width | — |
| Overall Height | — |
| Seat Height | — |
| Wheelbase | 1220 mm / 48.0 in |
| Ground Clearance | — |
| Dry Weight | — |
| Wet Weight | — |
| WHEEL SPECS | |
| Front Tyre | 19 in, high pressure |
| Rear Tyre | 19 in, high pressure |
| FUEL SYSTEM | |
| Fuel Capacity | 6.5 Litres / 1.7 US gal (8 Litres / 2.1 US gal from 1950) |
| Fuel Consumption | 1.9 l/100 km |
| Top Speed | 85 km/h / 52.8 mph |
The Fox was NSU's first post-war motorcycle, shown in 1948 and sold from 1949. Its pressed-steel central frame was chosen to suit mass production, and its small four-stroke could reach 85 km/h, unusual for a 100 cc bike then. A two-stroke variant followed in 1951 and the line ended with the Superfox.
