Data as of: DVSA MOT results to 2025
Triumph Rocket Iii vs Harley-Davidson Fxsb
The Harley-Davidson Fxsb passes its MOT first time more often than the Triumph Rocket Iii: 89.3% vs 88.3%, a 1.0-point lead.
MOT reliability, side by side
| Metric | Triumph Rocket Iii | Harley-Davidson Fxsb |
|---|---|---|
| First-time pass rate | 88.3% | 89.3% |
| Outright fail rate | 6.1% | 4.4% |
| Vs comparable bikes (age & mileage adjusted) | +2.7 pts | +1.4 pts |
| Engine size | 2,294cc | 1,690cc |
| Rank among all models | #1505 of 5428 | #1180 of 5428 |
| Median miles at test | 13,110 | 6,609 |
| MOT tests analysed | 15,488 | 6,915 |
| 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 Rocket Iii | Harley-Davidson Fxsb |
|---|---|---|
| Lights & signalling | 2.3% | 2.8% |
| Tyres & wheels | 2.0% | 0.8% |
| Brakes | 1.8% | 0.5% |
| Steering & suspension | 0.7% | 0.4% |
| Fuel & exhaust | 0.6% | 0.0% |
| Structure & body | 0.2% | 0.4% |
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 Rocket Iii | Harley-Davidson Fxsb |
|---|---|---|
| 2018 | 89.2% | 85.3% |
| 2019 | 88.4% | 88.9% |
| 2020 | 88.4% | 90.6% |
| 2021 | 88.5% | 91.1% |
| 2022 | 88.7% | 90.4% |
| 2023 | 89.3% | 90.8% |
| 2024 | 90.7% | 90.1% |
| 2025 | 88.3% | 88.7% |
Each year mixes bikes of different ages, so a fleet that is getting older tends to slip.
Pass rate by mileage
| Mileage | Triumph Rocket Iii | Harley-Davidson Fxsb |
|---|---|---|
| 0k-10k miles | 89.2% | 89.7% |
| 10k-20k miles | 88.6% | 88.7% |
| 20k-30k miles | 87.7% | 88.6% |
| 30k-40k miles | 85.1% | 84.8% |
Bands with fewer than 30 tests for either bike are left out.
Triumph Rocket Iii vs Harley-Davidson Fxsb FAQ
Which is more reliable, the Triumph Rocket Iii or the Harley-Davidson Fxsb?
The Harley-Davidson Fxsb passes its MOT first time more often than the Triumph Rocket Iii: 89.3% vs 88.3%, a 1.0-point lead. Adjusted for age, mileage and test class, the Triumph Rocket Iii still comes out ahead: +2.7 points vs comparable bikes for the Triumph Rocket Iii, +1.4 for the Harley-Davidson Fxsb. An MOT checks roadworthiness items, not engine or gearbox internals.
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%).
What does the Harley-Davidson Fxsb fail its MOT on most?
Lights & signalling: 2.8% of Harley-Davidson Fxsb MOT tests failed on it, then tyres & wheels (0.8%).
Which holds up better at high mileage, the Triumph Rocket Iii or the Harley-Davidson Fxsb?
They are level: at 30k-40k miles the Triumph Rocket Iii passes 85.1% first time and the Harley-Davidson Fxsb 84.8%.
See each bike's full report (trend, mileage curve, failure breakdown and rivals) on its own page.