| MODEL | ARIEL 4G SQUARE FOUR MARK I 1952 |
| Year | 1952 |
| Engine Type | Square four, OHV |
| Displacement / Capacity | 995 cc |
| Bore X Stroke | 65 x 78 mm / 2.56 x 3.07 in |
| Compression Ratio | 6:1 |
| Cooling System | Air |
| Max Power | 26.1 kW / 35 hp @ 5500 rpm |
| Max Torque | — |
| Ignition | — |
| Induction | Carburettor |
| Start System | Kick |
| TRANSMISSION SPECS | |
| Lubrication | — |
| Gear Box | 4-speed |
| Clutch | — |
| Final Drive | Chain |
| CHASSIS SPECS | |
| Frame | — |
| Front Suspension | — |
| Rear Suspension | — |
| Front Brakes | Expanding brake (drum), 203 mm / 8 in |
| Rear Brakes | Expanding brake (drum), 178 mm / 7 in |
| DIMENSION SPECS | |
| Overall Length | 2082 mm / 82 in |
| Overall Width | — |
| Overall Height | — |
| Seat Height | — |
| Wheelbase | 1422 mm / 56 in |
| Ground Clearance | — |
| Dry Weight | 197 kg / 434.3 lb |
| Wet Weight | — |
| WHEEL SPECS | |
| Front Tyre | 3.25-19 |
| Rear Tyre | 4.00-18 |
| FUEL SYSTEM | |
| Fuel Capacity | 16 Litres / 4.2 US gal |
| Fuel Consumption | — |
| Top Speed | 144.8 km/h / 90 mph |
The Mark I was the postwar Ariel Square Four, a 995 cc overhead-valve air-cooled four with a cast-iron engine and four-speed gearbox. It kept the rigid-frame, girder-fork chassis of the prewar bike, with a roomy fuel tank and the smooth, torquey character of the Square Four layout.
