Data as of: DVSA MOT results to 2025
Honda ST50-K vs Piaggio Zip
The Honda ST50-K passes its MOT first time more often than the Piaggio Zip: 91.4% vs 71.3%, a 20.1-point lead.
MOT reliability, side by side
| Metric | Honda ST50-K | Piaggio Zip |
|---|---|---|
| First-time pass rate | 91.4% | 71.3% |
| Outright fail rate | 4.0% | 20.4% |
| Vs comparable bikes (age & mileage adjusted) | +11.9 pts | -1.0 pts |
| Engine size | 49cc | 49cc |
| Rank among all models | #588 of 5428 | #4631 of 5428 |
| Median miles at test | 3,146 | 8,882 |
| MOT tests analysed | 607 | 78,993 |
| Most common failure | lighting and signalling | 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 | Honda ST50-K | Piaggio Zip |
|---|---|---|
| Lights & signalling | 2.5% | 11.9% |
| Steering & suspension | 1.0% | 9.2% |
| Brakes | 0.7% | 6.5% |
| Tyres & wheels | 0.5% | 4.0% |
| Fuel & exhaust | 0.3% | 2.5% |
| Structure & body | 0.7% | 1.6% |
| Drive system | 0.7% | 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 | Honda ST50-K | Piaggio Zip |
|---|---|---|
| 2009 | 92.1% | 70.0% |
| 2010 | 95.2% | 70.8% |
| 2011 | 93.2% | 69.7% |
| 2012 | 87.5% | 69.1% |
| 2013 | 89.2% | 69.7% |
| 2014 | 89.2% | 68.8% |
| 2015 | 90.5% | 69.8% |
| 2017 | 93.5% | 71.7% |
Each year mixes bikes of different ages, so a fleet that is getting older tends to slip.
Pass rate by mileage
| Mileage | Honda ST50-K | Piaggio Zip |
|---|---|---|
| 0k-10k miles | 91.9% | 75.2% |
| 10k-20k miles | 88.2% | 66.7% |
Bands with fewer than 30 tests for either bike are left out.
Honda ST50-K vs Piaggio Zip FAQ
Which is more reliable, the Honda ST50-K or the Piaggio Zip?
The Honda ST50-K passes its MOT first time more often than the Piaggio Zip: 91.4% vs 71.3%, a 20.1-point lead. Adjusted for age, mileage and test class, the Honda ST50-K still comes out ahead: +11.9 points vs comparable bikes for the Honda ST50-K, -1.0 for the Piaggio Zip. An MOT checks roadworthiness items, not engine or gearbox internals.
What does the Honda ST50-K fail its MOT on most?
Lights & signalling: 2.5% of Honda ST50-K MOT tests failed on it, then steering & suspension (1.0%).
What does the Piaggio Zip fail its MOT on most?
Lights & signalling: 11.9% of Piaggio Zip MOT tests failed on it, then steering & suspension (9.2%).
See each bike's full report (trend, mileage curve, failure breakdown and rivals) on its own page.