
Ariel 4G Square Four Mark I
Key specifications
Overview
Introducing the 1951 Ariel 4G Square Four Mark I The 1951 Ariel 4G Square Four Mark I, affectionately nicknamed the "Squariel," stands as a testament to British engineering and design brilliance. Positioned in the all-round category, this motorcycle appeals to enthusiasts seeking a blend of power, style, and nostalgia. Designed by the legendary Edward Turner, the Square Four is instantly recognizable for its unique square four-cylinder engine configuration, which not only distinguishes it visually but also sets it apart in performance. As the motorcycle market burgeoned in the post-war era, the Ariel 4G emerged as a versatile option for riders craving both daily commuting efficiency and weekend adventure. Engine Performance and Riding Characteristics At the heart of the Ariel 4G lies a robust 995 cc square four-cylinder engine that produces an exhilarating 35 HP at 5,500 RPM, making it capable of reaching a top speed of 144.8 km/h (90.0 mph). This power, coupled with a 6.0:1 compression ratio, ensures a spirited ride whether navigating city streets or cruising on open highways. The engine's smooth torque delivery enhances the riding experience, while the 4-speed gearbox offers seamless shifts that cater to both relaxed rides and spirited acceleration. The air-cooled setup, along with the SU MC2 carburettor, provides reliability and ease of maintenance—a crucial factor for riders who appreciate the charm of vintage mechanics. Key Features and Technology The Ariel 4G Square Four Mark I doesn't just rest on its laurels with impressive engine specs; it also boasts an innovative tubular single-loop frame for improved rigidity and handling. The oil-damped telescopic front fork and plunger-link rear suspension work in tandem to deliver a comfortable and stable ride, even on uneven terrains. The braking system, featuring drum brakes with generous diameters of 203 mm at the front and 178 mm at the rear, provides ample stopping power. A fuel capacity of 16 liters (4.23 gallons) ensures that riders can enjoy extended journeys without frequent stops. The classic red and chrome color options further accentuate its vintage appeal, making it a head-turner in any setting. **
Pros
Cons
- Unique Square Four engine design offers distinctive performance and character.
- Comfortable riding experience due to advanced suspension technology for its time.
- Reliable and easy-to-maintain components, making it suitable for both enthusiasts and daily riders.
- Weighty at 197 kg (434.3 pounds), which may affect maneuverability for some riders.
- Drum brakes, while adequate, may not provide the stopping power expected by modern standards.
- Limited aftermarket support compared to more mainstream brands, potentially making parts harder to source.
Technical details
Source specification data
- Make
- Ariel
- Model
- 4G Square Four Mark I
- Category
- Allround
- Light
- 30 Watt headlamp.
- Starter
- Kick
- Comments
- Also
- called ´
- Squariel
- ´.
- Designed
- by
- Edward Turner
- .
- Electrical
- 6 Volt battery.
- Color Options
- Red/chrome
- Power
- 35.00 HP (25.5 kW)) @ 5500 RPM
- Gearbox
- 4-speed
- Top Speed
- 144.8 km/h (90.0 mph)
- Engine Type
- Double twin cylinder arranged as a square.
- Fuel System
- Carburettor. SU MC2 carburettor
- Bore X Stroke
- 65.0 x 78.0 mm (2.6 x 3.1 inches)
- Compression
- 6.0:1
- Displacement
- 995.00 ccm (60.71 cubic inches)
- Cooling System
- Air
- Engine Details
- Square four cylinder
- Exhaust System
- Dual two-into-one
- Lubrication System
- Dry sump with dual oil pump.
- Valves Per Cylinder
- 2
- Transmission Type Final Drive
- Chain
- Dry Weight
- 197.0 kg (434.3 pounds)
- Fuel Capacity
- 16.00 litres (4.23 gallons)
- Overall Length
- 2,083 mm (82.0 inches)
- Power Weight Ratio
- 0.1777 HP/kg
- Seat
- Solo seat
- Wheels
- Wire spoked
- Rear Tyre
- 4.00-18
- Frame Type
- Tubular single loop
- Front Tyre
- 3.25-19
- Rear Brakes
- Expanding brake (drum brake)
- Front Brakes
- Expanding brake (drum brake)
- Rear Suspension
- Plunger-link spring
- Front Suspension
- Oil damped telescopic fork
- Rear Brakes Diameter
- 178 mm (7.0 inches)
- Front Brakes Diameter
- 203 mm (8.0 inches)