Data as of: DVSA MOT results to 2025
TRIUMPH BONNEVILLE T120
The pass rate is the MOT first-time pass: a roadworthiness check of the items an MOT covers (brakes, lights, tyres, steering, structure, emissions), not a full mechanical inspection of engine or gearbox internals. It is a reliability signal, not a complete measure of mechanical reliability. What this measures.
“vs expected” adjusts for age, mileage and test class, so a cherished classic and a hard-used commuter are compared fairly. How this works.
Pass rate over time
The BONNEVILLE T120's first-time pass rate has risen 3.5 points since 2024, 89.8% to 93.3%.
What fails on a BONNEVILLE T120
| Component group | Share of defects | Defects | % of defects | vs all bikes |
|---|---|---|---|---|
| lamps and reflectors |
|
15 | 36.6 | 0.9× |
| steering and suspension |
|
6 | 14.6 | 0.2× |
| tyres |
|
4 | 9.8 | 0.8× |
| lighting and signalling |
|
4 | 9.8 | 0.1× |
| Identification of the vehicle |
|
3 | 7.3 | 1.8× |
| suspension |
|
2 | 4.9 | 0.4× |
| steering |
|
2 | 4.9 | 0.7× |
| brakes |
|
2 | 4.9 | 0.1× |
| structure and attachments |
|
2 | 4.9 | 0.4× |
| audible warning (Horn) |
|
1 | 2.4 | 0.8× |
Defects recorded against failed normal tests, 2005–2025, grouped by DVSA inspection section. One test can record multiple defects. "vs all bikes" is how often this model's tests record a defect in the group, as a multiple of the all-bike rate.
How rivals compare
On first-time pass rate the BONNEVILLE T120 beats 4 of its 4 closest rivals (TRIUMPH BONNEVILLE, TRIUMPH THUNDERBIRD, HARLEY-DAVIDSON XLH 883).
Rivals share this bike's type and sit within ±30% of its engine capacity, ≥ 5,000 tests. Card colour = better/worse first-time pass rate than the BONNEVILLE T120.
Compare with any bike
More TRIUMPH models
Pass rate by registration year
Highest pass rate: 1970 (96.6%). Lowest: 2021 (89.7%). Every Bonneville T120 year compared →
First-time pass rate by the year each bike was first registered (cohorts with ≥ 50 tests). Older cohorts are survivors: the worst examples have already left the road, which tends to lift the earliest years.
TRIUMPH BONNEVILLE T120 FAQ
Is the TRIUMPH BONNEVILLE T120 reliable?
The TRIUMPH BONNEVILLE T120 is more reliable than average for its class: 92.1% of its 724 MOT tests (2005–2025) passed first time, against a class average of 84.9%. That ranks it #455 of 5428 models.
What does a BONNEVILLE T120 fail its MOT on most?
lamps and reflectors: 37% of all defects recorded against failed BONNEVILLE T120 tests.
What is the best year of BONNEVILLE T120 to buy used?
By first-time pass rate, 1970-registered examples do best (96.6%) and 2021 worst (89.7%). Condition and history still trump the year.
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