Pass rate over time
The GP1's first-time pass rate has risen 5.9 points since 2009, 61.8% to 67.7%.
What fails on a GP1
| Component group | Share of defects | Defects | % of defects | vs all bikes |
|---|---|---|---|---|
| lighting and signalling |
|
219 | 38.9 | 3.6× |
| brakes |
|
113 | 20.1 | 2.6× |
| steering and suspension |
|
101 | 17.9 | 3.4× |
| fuel and exhaust |
|
29 | 5.2 | 4.5× |
| lamps and reflectors |
|
28 | 5 | 1.2× |
| tyres and wheels |
|
23 | 4.1 | 1.5× |
| body and structure |
|
18 | 3.2 | 3.9× |
| drive system |
|
14 | 2.5 | 1.7× |
| structure and attachments |
|
9 | 1.6 | 1.2× |
| reg plates and vin |
|
9 | 1.6 | 2.1× |
Defects recorded against failed normal tests, 2005–2025, grouped by DVSA inspection section. One test can record multiple defects. "vs all bikes" is how often this model's tests record a defect in the group, as a multiple of the all-bike rate.
How rivals compare
On first-time pass rate the GP1 beats 2 of its 4 closest rivals (PEUGEOT SPEEDFIGHT, PIAGGIO ZIP, PIAGGIO NRG).
Rivals share this bike's type and sit within ±30% of its engine capacity, ≥ 5,000 tests. Card colour = better/worse first-time pass rate than the GP1.
Pass rate by registration year
Best year to buy used: 2010 (77.4% pass). Weakest: 2007 (60.3%).
First-time pass rate by the year each bike was first registered (cohorts with ≥ 50 tests). Older cohorts are survivors: the worst examples have already left the road, which tends to lift the earliest years.
DERBI GP1 FAQ
Is the DERBI GP1 reliable?
The DERBI GP1 is less reliable than average for its class: 66.0% of its 754 MOT tests (2005–2025) passed first time, against a class average of 73.4%. That ranks it #4966 of 5426 models.
What does a GP1 fail its MOT on most?
lighting and signalling — 39% of all defects recorded against failed GP1 tests.
What is the best year of GP1 to buy used?
By first-time pass rate, 2010-registered examples do best (77.4%) and 2007 worst (60.3%). Condition and history still trump the year.