Triumph Bonneville street twin a2l vs Triumph Unknown: reliability comparison
MOT pass rates, common faults and mileage compared from real UK MOT data.
Triumph Bonneville street twin a2l
83%
MOT pass rate · 1 vehicles
Triumph Unknown
89%
MOT pass rate · 65,927 vehicles
Verdict: On MOT pass rate the Triumph Bonneville street twin a2l (83%) and Triumph Unknown (89%) are very close — weigh the individual measures below, and remember condition depends on age, mileage and upkeep.
Head to head
| Measure | Triumph Bonneville street twin a2l | Triumph Unknown |
|---|---|---|
| MOT pass rate | 83% | 89% ✓ |
| MOT failure rate | 17% | 11% ✓ |
| Faults & advisories per test | 0.0 ✓ | 0.6 |
| Dangerous-fault share | — ✓ | 2% |
| Average mileage | 5,580 mi | 16,601 mi |
| Sample size (vehicles) | 1 | 65,927 |
Most common faults
Triumph Bonneville street twin a2l
- Horn not working (7.7 (a))
- Wheel alignment incorrect which adversely affects the handling (2.4 (a))
Triumph Unknown
- Exhaust noisy (8.1.1 (a))
- Exhaust noisy (7.1.2)
- Front Roller brake test indicates slight fluctuation of brake effort (3.3.A1d)
- COVID-19 6 MONTH EXTENSION
- Rear Tyre worn close to the legal limit (5.2.3 (e))
- Steering headbearing has slight free play (2.2.2)
Reliability FAQ
On MOT pass rate the Triumph Bonneville street twin a2l (83%) and Triumph Unknown (89%) are very close — weigh the individual measures below, and remember condition depends on age, mileage and upkeep.
Full Triumph Bonneville street twin a2l report Full Triumph Unknown report Most reliable cars
Pass rates are computed over completed (pass/fail) MOT tests. Reliability also depends on age, mileage and upkeep — see each model's page for the full picture.