Data as of: DVSA MOT results to 2025
Triumph Thunderbird 1600 vs Harley-Davidson XL1200C
The Triumph Thunderbird 1600 passes its MOT first time more often than the Harley-Davidson XL1200C: 89.6% vs 88.4%, a 1.2-point lead.
MOT reliability, side by side
| Metric | Triumph Thunderbird 1600 | Harley-Davidson XL1200C |
|---|---|---|
| First-time pass rate | 89.6% | 88.4% |
| Outright fail rate | 5.8% | 5.7% |
| Vs comparable bikes (age & mileage adjusted) | +3.2 pts | +2.3 pts |
| Engine size | 1,600cc | 1,200cc |
| Rank among all models | #1077 of 5428 | #1478 of 5428 |
| Median miles at test | 10,936 | 9,976 |
| MOT tests analysed | 4,547 | 15,738 |
| Most common failure | brakes | lighting and signalling |
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 Thunderbird 1600 | Harley-Davidson XL1200C |
|---|---|---|
| Lights & signalling | 1.4% | 2.5% |
| Brakes | 2.3% | 1.2% |
| Tyres & wheels | 1.9% | 1.1% |
| Fuel & exhaust | 0.6% | 0.8% |
| Steering & suspension | 0.5% | 0.8% |
| Structure & body | 0.2% | 0.3% |
| 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 Thunderbird 1600 | Harley-Davidson XL1200C |
|---|---|---|
| 2018 | 90.5% | 90.7% |
| 2019 | 86.3% | 89.2% |
| 2020 | 94.5% | 91.8% |
| 2021 | 90.5% | 90.0% |
| 2022 | 87.0% | 88.3% |
| 2023 | 89.6% | 88.7% |
| 2024 | 86.9% | 90.8% |
| 2025 | 89.5% | 88.9% |
Each year mixes bikes of different ages, so a fleet that is getting older tends to slip.
Pass rate by mileage
| Mileage | Triumph Thunderbird 1600 | Harley-Davidson XL1200C |
|---|---|---|
| 0k-10k miles | 92.5% | 89.9% |
| 10k-20k miles | 88.4% | 88.1% |
| 20k-30k miles | 86.2% | 86.1% |
| 30k-40k miles | 82.1% | 86.1% |
| 40k-50k miles | 84.1% | 80.3% |
Bands with fewer than 30 tests for either bike are left out.
Triumph Thunderbird 1600 vs Harley-Davidson XL1200C FAQ
Which is more reliable, the Triumph Thunderbird 1600 or the Harley-Davidson XL1200C?
The Triumph Thunderbird 1600 passes its MOT first time more often than the Harley-Davidson XL1200C: 89.6% vs 88.4%, a 1.2-point lead. Adjusted for age, mileage and test class the two are level (+3.2 vs +2.3 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 Thunderbird 1600 fail its MOT on most?
Brakes: 2.3% of Triumph Thunderbird 1600 MOT tests failed on it, then tyres & wheels (1.9%).
What does the Harley-Davidson XL1200C fail its MOT on most?
Lights & signalling: 2.5% of Harley-Davidson XL1200C MOT tests failed on it, then brakes (1.2%).
Which holds up better at high mileage, the Triumph Thunderbird 1600 or the Harley-Davidson XL1200C?
At 40k-50k miles the Triumph Thunderbird 1600 passes first time more often: 84.1% for the Triumph Thunderbird 1600 vs 80.3% for the Harley-Davidson XL1200C.
See each bike's full report (trend, mileage curve, failure breakdown and rivals) on its own page.