Data as of: DVSA MOT results to 2025
Triumph Thunderbird 1600 vs Harley-Davidson Fxdwg
The Triumph Thunderbird 1600 passes its MOT first time more often than the Harley-Davidson Fxdwg: 89.6% vs 88.7%, a 0.9-point lead.
MOT reliability, side by side
| Metric | Triumph Thunderbird 1600 | Harley-Davidson Fxdwg |
|---|---|---|
| First-time pass rate | 89.6% | 88.7% |
| Outright fail rate | 5.8% | 5.0% |
| Vs comparable bikes (age & mileage adjusted) | +3.2 pts | +4.2 pts |
| Engine size | 1,600cc | 1,450cc |
| Rank among all models | #1077 of 5428 | #1370 of 5428 |
| Median miles at test | 10,936 | 16,028 |
| MOT tests analysed | 4,547 | 14,585 |
| 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 Fxdwg |
|---|---|---|
| Lights & signalling | 1.4% | 2.5% |
| Brakes | 2.3% | 1.2% |
| Tyres & wheels | 1.9% | 1.1% |
| Steering & suspension | 0.5% | 0.8% |
| Fuel & exhaust | 0.6% | 0.6% |
| 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 Fxdwg |
|---|---|---|
| 2018 | 90.5% | 87.6% |
| 2019 | 86.3% | 89.5% |
| 2020 | 94.5% | 90.7% |
| 2021 | 90.5% | 89.2% |
| 2022 | 87.0% | 87.2% |
| 2023 | 89.6% | 91.6% |
| 2024 | 86.9% | 88.4% |
| 2025 | 89.5% | 90.7% |
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 Fxdwg |
|---|---|---|
| 0k-10k miles | 92.5% | 90.6% |
| 10k-20k miles | 88.4% | 88.4% |
| 20k-30k miles | 86.2% | 88.6% |
| 30k-40k miles | 82.1% | 88.1% |
| 40k-50k miles | 84.1% | 84.5% |
Bands with fewer than 30 tests for either bike are left out.
Triumph Thunderbird 1600 vs Harley-Davidson Fxdwg FAQ
Which is more reliable, the Triumph Thunderbird 1600 or the Harley-Davidson Fxdwg?
The Triumph Thunderbird 1600 passes its MOT first time more often than the Harley-Davidson Fxdwg: 89.6% vs 88.7%, a 0.9-point lead. Adjusted for age, mileage and test class, the Harley-Davidson Fxdwg still comes out ahead: +3.2 points vs comparable bikes for the Triumph Thunderbird 1600, +4.2 for the Harley-Davidson Fxdwg. 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 Fxdwg fail its MOT on most?
Lights & signalling: 2.5% of Harley-Davidson Fxdwg MOT tests failed on it, then brakes (1.2%).
Which holds up better at high mileage, the Triumph Thunderbird 1600 or the Harley-Davidson Fxdwg?
They are level: at 40k-50k miles the Triumph Thunderbird 1600 passes 84.1% first time and the Harley-Davidson Fxdwg 84.5%.
See each bike's full report (trend, mileage curve, failure breakdown and rivals) on its own page.