Pass rate over time
The TERRA's first-time pass rate has fallen 1.2 points since 2013, 73.0% to 71.8%.
What fails on a TERRA
| Component group | Share of defects | Defects | % of defects | vs all bikes |
|---|---|---|---|---|
| lamps and reflectors |
|
66 | 22 | 4.0× |
| brakes |
|
65 | 21.7 | 1.5× |
| structure and attachments |
|
39 | 13 | 5.1× |
| lighting and signalling |
|
32 | 10.7 | 0.7× |
| suspension |
|
28 | 9.3 | 3.8× |
| steering and suspension |
|
20 | 6.7 | 0.6× |
| drive system |
|
19 | 6.3 | 2.4× |
| steering |
|
16 | 5.3 | 4.5× |
| tyres |
|
9 | 3 | 1.8× |
| tyres and wheels |
|
6 | 2 | 0.4× |
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 TERRA beats 2 of its 4 closest rivals (YAMAHA YBR 125, HONDA CG125, HONDA CBF125).
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 TERRA.
Pass rate by registration year
Best year to buy used: 2015 (76.5% pass). Weakest: 2009 (65.3%).
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 TERRA FAQ
Is the DERBI TERRA reliable?
The DERBI TERRA is less reliable than average for its class: 71.1% of its 744 MOT tests (2005–2025) passed first time, against a class average of 73.4%. That ranks it #4650 of 5426 models.
What does a TERRA fail its MOT on most?
lamps and reflectors — 22% of all defects recorded against failed TERRA tests.
What is the best year of TERRA to buy used?
By first-time pass rate, 2015-registered examples do best (76.5%) and 2009 worst (65.3%). Condition and history still trump the year.