Data as of: DVSA MOT results to 2025
Triumph Bonneville America vs Harley-Davidson XL
The Harley-Davidson XL passes its MOT first time more often than the Triumph Bonneville America: 87.9% vs 85.7%, a 2.2-point lead.
MOT reliability, side by side
| Metric | Triumph Bonneville America | Harley-Davidson XL |
|---|---|---|
| First-time pass rate | 85.7% | 87.9% |
| Outright fail rate | 7.1% | 5.3% |
| Vs comparable bikes (age & mileage adjusted) | -0.9 pts | -0.1 pts |
| Engine size | 865cc | 883cc |
| Rank among all models | #2308 of 5428 | #1639 of 5428 |
| Median miles at test | 9,728 | 6,108 |
| MOT tests analysed | 6,025 | 18,541 |
| Most common failure | brakes | lamps and reflectors |
First-time outcomes on normal tests, 2005–2025. "Most common failure" is the component group with the most recorded defects on failed tests. Read pass rates against test counts: a smaller sample is noisier. Source: DVSA anonymised MOT results.
"Vs comparable bikes" is the first-time pass rate minus the rate expected for each bike's own mix of age, mileage and test class, in percentage points: positive means better than comparable bikes. How this works.
What fails, side by side
| Component | Triumph Bonneville America | Harley-Davidson XL |
|---|---|---|
| Lights & signalling | 2.4% | 3.0% |
| Brakes | 2.5% | 0.8% |
| Tyres & wheels | 1.8% | 0.5% |
| Steering & suspension | 1.1% | 0.9% |
| Structure & body | 0.5% | 1.0% |
| Fuel & exhaust | 0.6% | 0.1% |
| Drive system | 0.2% | 0.0% |
A test that fails on two components counts once in each. Component links go to the bikes most likely to fail on it.
Pass rate by test year
| Test year | Triumph Bonneville America | Harley-Davidson XL |
|---|---|---|
| 2018 | 89.0% | 87.1% |
| 2019 | 87.0% | 86.5% |
| 2020 | 85.1% | 89.4% |
| 2021 | 82.0% | 88.8% |
| 2022 | 85.5% | 88.5% |
| 2023 | 88.4% | 88.4% |
| 2024 | 84.9% | 87.6% |
| 2025 | 88.8% | 87.5% |
Each year mixes bikes of different ages, so a fleet that is getting older tends to slip.
Pass rate by mileage
| Mileage | Triumph Bonneville America | Harley-Davidson XL |
|---|---|---|
| 0k-10k miles | 87.4% | 89.0% |
| 10k-20k miles | 85.6% | 85.5% |
| 20k-30k miles | 81.3% | 85.6% |
| 30k-40k miles | 80.5% | 83.6% |
| 40k-50k miles | 77.1% | 82.3% |
Bands with fewer than 30 tests for either bike are left out.
Triumph Bonneville America vs Harley-Davidson XL FAQ
Which is more reliable, the Triumph Bonneville America or the Harley-Davidson XL?
The Harley-Davidson XL passes its MOT first time more often than the Triumph Bonneville America: 87.9% vs 85.7%, a 2.2-point lead. Adjusted for age, mileage and test class the two are level (-0.9 vs -0.1 points against comparable bikes), so the raw gap is mostly down to how old and how used each fleet is. An MOT checks roadworthiness items, not engine or gearbox internals.
What does the Triumph Bonneville America fail its MOT on most?
Brakes: 2.5% of Triumph Bonneville America MOT tests failed on it, then lights & signalling (2.4%).
What does the Harley-Davidson XL fail its MOT on most?
Lights & signalling: 3.0% of Harley-Davidson XL MOT tests failed on it, then structure & body (1.0%).
Which holds up better at high mileage, the Triumph Bonneville America or the Harley-Davidson XL?
At 40k-50k miles the Harley-Davidson XL passes first time more often: 77.1% for the Triumph Bonneville America vs 82.3% for the Harley-Davidson XL.
See each bike's full report (trend, mileage curve, failure breakdown and rivals) on its own page.