The 1959 Triumph Bonneville T120 from United Kingdom was powered by a 649cc OHV twin producing 46hp at 6500rpm. Weighing 172.0kg (379 lbs) and with a seat height of 790mm, it was aimed at standard riders.
The 1955 BSA B33 by contrast offered 499cc of OHV single power, delivering 23hp at 5500rpm. Tipping the scales at 170.0kg (375 lbs) with a top speed of 130km/h (81 mph), it offered a distinct riding experience. 1950s bikes represent the golden age of British motorcycling and early Japanese innovation, with well-maintained examples commanding premium prices.
Specifications Comparison
| 1959 Triumph Bonneville T120 | 1955 BSA B33 | |
|---|---|---|
| Displacement | 649 cc | 499 cc |
| Power | 46 hp | 23 hp |
| Torque | 52.0 Nm | 35.0 Nm |
| Cylinders | 2 | 1 |
| Top Speed | 177 km/h | 130 km/h |
| Quarter Mile | — | — |
| Dry Weight | 172.0 kg | 170.0 kg |
| Wet Weight | 185.0 kg | 183.0 kg |
| Seat Height | 790 mm | 780 mm |
| Wheelbase | 1400 mm | 1370 mm |
| Fuel Capacity | 14.0 L | 14.0 L |
| Gears | 4 -speed | 4 -speed |
The Verdict
For pure standard performance, the 1959 Triumph Bonneville T120 has the edge thanks to more power (46hp vs 23hp) and a higher top speed. The 1955 BSA B33, however, excels when all-round versatility and everyday riding is the priority and offers a lighter package. For collectors, the 1959 Triumph Bonneville T120 commands more attention with a 9/10 collectibility rating. Parts availability is good for the 1959 Triumph Bonneville T120 and moderate for the 1955 BSA B33 — an important factor for any restoration project.
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 →About the 1955 BSA B33
The 1955 1955 BSA B33 is a 499cc single-cylinder standard motorcycle that became one of BSA's most memorable motorcycles of the 1950s.
Full 1955 BSA B33 Profile →