Data as of: DVSA MOT results to 2025
Harley-Davidson Pro Street Breakout 1801 17 vs Triumph Rocket Iii
The Harley-Davidson Pro Street Breakout 1801 17 passes its MOT first time more often than the Triumph Rocket Iii: 94.2% vs 88.3%, a 5.9-point lead.
MOT reliability, side by side
| Metric | Harley-Davidson Pro Street Breakout 1801 17 | Triumph Rocket Iii |
|---|---|---|
| First-time pass rate | 94.2% | 88.3% |
| Outright fail rate | 2.2% | 6.1% |
| Vs comparable bikes (age & mileage adjusted) | +5.6 pts | +2.7 pts |
| Engine size | 1,801cc | 2,294cc |
| Rank among all models | #143 of 5428 | #1505 of 5428 |
| Median miles at test | 7,109 | 13,110 |
| MOT tests analysed | 675 | 15,488 |
| Most common failure | lamps and reflectors | brakes |
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 | Harley-Davidson Pro Street Breakout 1801 17 | Triumph Rocket Iii |
|---|---|---|
| Lights & signalling | 0.9% | 2.3% |
| Tyres & wheels | 0.3% | 2.0% |
| Brakes | 0.4% | 1.8% |
| Steering & suspension | 0.1% | 0.7% |
| Fuel & exhaust | 0% | 0.6% |
| Structure & body | 0.1% | 0.2% |
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 | Harley-Davidson Pro Street Breakout 1801 17 | Triumph Rocket Iii |
|---|---|---|
| 2020 | 96.3% | 88.4% |
| 2021 | 93.1% | 88.5% |
| 2022 | 94.9% | 88.7% |
| 2023 | 91.6% | 89.3% |
| 2024 | 96.4% | 90.7% |
| 2025 | 93.8% | 88.3% |
Each year mixes bikes of different ages, so a fleet that is getting older tends to slip.
Pass rate by mileage
| Mileage | Harley-Davidson Pro Street Breakout 1801 17 | Triumph Rocket Iii |
|---|---|---|
| 0k-10k miles | 93.6% | 89.2% |
| 10k-20k miles | 94.3% | 88.6% |
| 20k-30k miles | 90.3% | 87.7% |
Bands with fewer than 30 tests for either bike are left out.
Harley-Davidson Pro Street Breakout 1801 17 vs Triumph Rocket Iii FAQ
Which is more reliable, the Harley-Davidson Pro Street Breakout 1801 17 or the Triumph Rocket Iii?
The Harley-Davidson Pro Street Breakout 1801 17 passes its MOT first time more often than the Triumph Rocket Iii: 94.2% vs 88.3%, a 5.9-point lead. Adjusted for age, mileage and test class, the Harley-Davidson Pro Street Breakout 1801 17 still comes out ahead: +5.6 points vs comparable bikes for the Harley-Davidson Pro Street Breakout 1801 17, +2.7 for the Triumph Rocket Iii. An MOT checks roadworthiness items, not engine or gearbox internals.
What does the Harley-Davidson Pro Street Breakout 1801 17 fail its MOT on most?
Lights & signalling: 0.9% of Harley-Davidson Pro Street Breakout 1801 17 MOT tests failed on it, then brakes (0.4%).
What does the Triumph Rocket Iii fail its MOT on most?
Lights & signalling: 2.3% of Triumph Rocket Iii MOT tests failed on it, then tyres & wheels (2.0%).
Which holds up better at high mileage, the Harley-Davidson Pro Street Breakout 1801 17 or the Triumph Rocket Iii?
At 20k-30k miles the Harley-Davidson Pro Street Breakout 1801 17 passes first time more often: 90.3% for the Harley-Davidson Pro Street Breakout 1801 17 vs 87.7% for the Triumph Rocket Iii.
See each bike's full report (trend, mileage curve, failure breakdown and rivals) on its own page.