| MODEL | TRIUMPH SPEED TWIN 500 1959 - 1963 |
| Year | 1959 - 1963 |
| Engine Type | Four stroke, parallel twin, OHV |
| Displacement / Capacity | 498 cc |
| Bore X Stroke | 63 x 80 mm |
| Compression Ratio | 7.2:1 |
| Cooling System | Air cooled |
| Max Power | 20.1 kW / 27 hp @ 6500 rpm |
| Max Torque | — |
| Ignition | 6 V magneto flywheel |
| Induction | Single Amal carburettor 15/16 in |
| Start System | Kick |
| TRANSMISSION SPECS | |
| Lubrication | — |
| Gear Box | 4 Speed, constant mesh |
| Clutch | Wet, 6 plate |
| Final Drive | Chain |
| CHASSIS SPECS | |
| Frame | Single tube frame |
| Front Suspension | Hydraulic telescopic fork |
| Rear Suspension | Swingarm with two shock absorbers |
| Front Brakes | Drum, 7 in SLS |
| Rear Brakes | Drum, 7 in SLS |
| DIMENSION SPECS | |
| Overall Length | — |
| Overall Width | — |
| Overall Height | — |
| Seat Height | 749 mm / 29.5 in |
| Wheelbase | 1372 mm / 54 in |
| Ground Clearance | 152 mm / 6.0 in |
| Dry Weight | 155 kg / 341 lbs |
| Wet Weight | — |
| WHEEL SPECS | |
| Front Tyre | 3.25 - 19 Dunlop Universal |
| Rear Tyre | 3.50 - 19 Dunlop Universal |
| FUEL SYSTEM | |
| Fuel Capacity | 18 Litres / 4.8 US gal |
| Fuel Consumption | — |
| Top Speed | — |
From 1959 the Speed Twin became the unit-construction 5TA, with engine and gearbox in one case and the controversial 'bathtub' rear enclosure that many owners removed. The enclosure shrank to a smaller 'bikini' in 1963 before conventional mudguards returned. Reviewers describe it as smooth, quiet and precise, better for relaxed back roads than fast cruising.
