The 1949 Triumph Thunderbird 6T from United Kingdom was powered by a 649cc OHV twin producing 34hp at 6000rpm. Weighing 180.0kg (397 lbs) and with a seat height of 790mm, it was aimed at standard riders.
The 1959 Triumph Bonneville T120 by contrast offered 649cc of OHV twin power, delivering 46hp at 6500rpm. Tipping the scales at 172.0kg (379 lbs) with a top speed of 177km/h (110 mph), it offered a distinct riding experience. 1940s motorcycles, especially military-era models, hold strong collector interest with values reflecting their historical significance.
Specifications Comparison
| 1949 Triumph Thunderbird 6T | 1959 Triumph Bonneville T120 | |
|---|---|---|
| Displacement | 649 cc | 649 cc |
| Power | 34 hp | 46 hp |
| Torque | 47.0 Nm | 52.0 Nm |
| Cylinders | 2 | 2 |
| Top Speed | 158 km/h | 177 km/h |
| Quarter Mile | — | — |
| Dry Weight | 180.0 kg | 172.0 kg |
| Wet Weight | 193.0 kg | 185.0 kg |
| Seat Height | 790 mm | 790 mm |
| Wheelbase | 1400 mm | 1400 mm |
| Fuel Capacity | 15.0 L | 14.0 L |
| Gears | 4 -speed | 4 -speed |
The Verdict
Comparing these two Triumph machines reveals the brand's evolution. The 1949 Triumph Thunderbird 6T laid the groundwork with 34hp, while the later 1959 Triumph Bonneville T120 pushed output to 46hp. From a collector's perspective, the 1959 Triumph Bonneville T120 holds the edge with a 9/10 rating. Either way, both are worthy additions to any Triumph collection. Parts availability is moderate for the 1949 Triumph Thunderbird 6T and good for the 1959 Triumph Bonneville T120 — an important factor for any restoration project.
About the 1949 Triumph Thunderbird 6T
The 1949 1949 Triumph Thunderbird 6T is a 649cc twin-cylinder standard motorcycle that became one of Triumph's most memorable motorcycles of the 1940s.
Full 1949 Triumph Thunderbird 6T Profile →About the 1959 Triumph Bonneville T120
The 1959 1959 Triumph Bonneville T120 packs a 649cc OHV twin engine with 46hp into a standard motorcycle package from Triumph.
Full 1959 Triumph Bonneville T120 Profile →