250F (1954-1958)
Several versions of this extraordinarily long-lived model, which starred on the world's circuits from 1954 to 1960, were developed. Engineering-wise it was inspired by the A6GCM and right from the very first series, delivered a very impressive 100 bhp per litre. Its stroke measurement was slightly lower than the bore.
The 250F's long development took place under the eagle eye of Ing. Giulio Alfieri and involved the engine, chassis and aerodynamics. Endless experiments carried out in the factory saw its performance improve and improve to the point where it became extremely competitive. Fuel-injected versions were also built and much testing was done using desmodromic valve control. Juan Manuel Fangio won the 1957 F1 World Championship title in the 250F.
Technical data
| 0-60 mph | |
| Bodywork | aluminium-bodied single seater |
| Bore and stroke | 84x75 mm |
| Brakes | hydraulic drum brakes on the wheels |
| Brakes front | |
| Brakes rear | |
| Chassis | tubular space-frame (from 1957) |
| Compression ratio | 12:1 (10.8:1 in 1958) |
| Cooling system | water-cooled, centrifugal pump |
| Displacements (unitary) | |
| Dry weight | 1,477-1,389 lbs (670-630 kg); 1958 1,212 lbs (550 kg) |
| Engine | in-line 6 |
| Engine weight | |
| First race | |
| Front Tyres | |
| Front suspension | helical springs, hydraulic Houdaille dampers and anti-roll bar |
| Front track | |
| Fuel & lubricant | |
| Fuel feed | naturally aspirated, three Weber 42 DCO3-45 DCO3 carburettors (also indirect and direct fuel injection in 1956) |
| Fuel tank | 44 Imp. gall. (200 litres) |
| Gear ratios | |
| Height | 37.40 in. (950 mm); from 1957 35.43 in. (900 mm) |
| Ignition | twin-plug, two Marelli magnetos |
| Kerb weight | |
| Length | 159.45 in. (4,050 mm); from 1957 168.11 in. (4,270 mm) |
| Length-Width-Height | |
| Lubrication | dual oil pumps (pressure and scavenge) |
| Maximum power | 240-270 bhp at 7,200-8,000 rpm |
| Maximum torque | |
| Model | 250F |
| One mile | |
| Production dates | 1954-1958 |
| Production start | 1954 |
| Quarter mile | |
| Rear Tyres | |
| Rear suspension | de Dion rear axle, transverse leaf spring, hydraulic Houdaille dampers and anti-roll bar |
| Rear track | |
| Reduction | |
| Steering | worm gear |
| Timing gear | two valves per cylinder, twin overhead camshafts |
| Top speed | 180 mph (290 km/h) |
| Total displacement | 2,493.8 cc |
| Transmission | 4-speed + reverse in unit with differential |
| Tyres | front 5.25x16-5.50x16-6.50x16; rear 6.50x16-7.00x16-7.00x17; Pirelli |
| Weight distribution | |
| Wheelbase | 89.76 in. (2,280 mm); from 1957 87.60 in. (2,225 mm) |
| Wheels | wire wheels, front 4.00x15, rear 5.50x16-6.00x17 |
| Width | 38.58 in. (980 mm); from 1957 35.82 in. (910 mm) |