Data as of: DVSA MOT results to 2025
Triumph Bonneville vs Harley-Davidson XL
The Triumph Bonneville passes its MOT first time more often than the Harley-Davidson XL: 89.0% vs 87.9%, a 1.1-point lead.
MOT reliability, side by side
| Metric | Triumph Bonneville | Harley-Davidson XL |
|---|---|---|
| First-time pass rate | 89.0% | 87.9% |
| Outright fail rate | 5.0% | 5.3% |
| Vs comparable bikes (age & mileage adjusted) | +1.6 pts | -0.1 pts |
| Engine size | 865cc | 883cc |
| Rank among all models | #1269 of 5428 | #1639 of 5428 |
| Median miles at test | 7,619 | 6,108 |
| MOT tests analysed | 195,256 | 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 | Harley-Davidson XL |
|---|---|---|
| Lights & signalling | 1.9% | 3.0% |
| Brakes | 1.9% | 0.8% |
| Steering & suspension | 0.7% | 0.9% |
| Tyres & wheels | 1.1% | 0.5% |
| Structure & body | 0.5% | 1.0% |
| Fuel & exhaust | 0.3% | 0.1% |
| Drive system | 0.1% | 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 | Harley-Davidson XL |
|---|---|---|
| 2018 | 88.7% | 87.1% |
| 2019 | 88.9% | 86.5% |
| 2020 | 91.1% | 89.4% |
| 2021 | 89.6% | 88.8% |
| 2022 | 89.4% | 88.5% |
| 2023 | 90.1% | 88.4% |
| 2024 | 90.6% | 87.6% |
| 2025 | 91.0% | 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 | Harley-Davidson XL |
|---|---|---|
| 0k-10k miles | 90.6% | 89.0% |
| 10k-20k miles | 86.8% | 85.5% |
| 20k-30k miles | 85.1% | 85.6% |
| 30k-40k miles | 85.8% | 83.6% |
| 40k-50k miles | 86.0% | 82.3% |
Bands with fewer than 30 tests for either bike are left out.
Triumph Bonneville vs Harley-Davidson XL FAQ
Which is more reliable, the Triumph Bonneville or the Harley-Davidson XL?
The Triumph Bonneville passes its MOT first time more often than the Harley-Davidson XL: 89.0% vs 87.9%, a 1.1-point lead. Adjusted for age, mileage and test class, the Triumph Bonneville still comes out ahead: +1.6 points vs comparable bikes for the Triumph Bonneville, -0.1 for the Harley-Davidson XL. An MOT checks roadworthiness items, not engine or gearbox internals.
What does the Triumph Bonneville fail its MOT on most?
Lights & signalling: 1.9% of Triumph Bonneville MOT tests failed on it, then brakes (1.9%).
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 or the Harley-Davidson XL?
At 40k-50k miles the Triumph Bonneville passes first time more often: 86.0% for the Triumph Bonneville 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.