| MODEL | TRIUMPH THUNDERBIRD 6T 1954 - 1962 |
| Year | 1954 - 1962 |
| Engine Type | Four-stroke, air-cooled OHV vertical twin |
| Displacement / Capacity | 649 cc |
| Bore X Stroke | 71 x 82 mm |
| Compression Ratio | 8.5:1 (export), 7.0:1 (UK) |
| Cooling System | Air cooled |
| Max Power | 25 kW / 34 hp @ 6500 rpm |
| Max Torque | — |
| Ignition | Lucas RM14 alternator system |
| Induction | SU MC2 carburettor |
| Start System | Kick |
| TRANSMISSION SPECS | |
| Lubrication | — |
| Gear Box | 4-speed constant mesh |
| Clutch | Wet, multi-plate |
| Final Drive | Chain, 101 links |
| CHASSIS SPECS | |
| Frame | Brazed lug swingarm frame |
| Front Suspension | Telescopic fork with hydraulic damping |
| Rear Suspension | Swingarm with two Girling dampers |
| Front Brakes | 8 in SLS drum |
| Rear Brakes | 7 in SLS drum |
| DIMENSION SPECS | |
| Overall Length | — |
| Overall Width | — |
| Overall Height | — |
| Seat Height | 775 mm / 31 in |
| Wheelbase | 1410 mm / 55.75 in |
| Ground Clearance | 127 mm / 5.0 in |
| Dry Weight | 179 kg / 395 lb |
| Wet Weight | — |
| WHEEL SPECS | |
| Front Tyre | 3.25 x 19 |
| Rear Tyre | 3.50 x 19 |
| FUEL SYSTEM | |
| Fuel Capacity | 13.6 Litres / 3.6 US gal (US); 18 Litres / 4.8 US gal (UK and export) |
| Fuel Consumption | — |
| Top Speed | — |
From 1954 the Thunderbird gained a swingarm frame, shortening the wheelbase slightly, along with a stiffer crank, a new oil tank housing the battery and air cleaner, and revised primary cases for an alternator. It became the milder road-oriented sibling of the sportier Tiger 110, and the early swingarm frame's tendency to flex earned it the 'Whip Iron' nickname.
