Derbi GPR50-R vs Piaggio NRG

The Piaggio NRG passes its MOT first time more often than the Derbi GPR50-R: 65.5% vs 53.4%, a 12.1-point lead.

MOT reliability, side by side

first-time pass rate, outright fail rate and tests analysed · 2005–2025

Metric	Derbi GPR50-R	Piaggio NRG
First-time pass rate	53.4%	65.5%
Outright fail rate	37.2%	27.4%
Vs comparable bikes (age & mileage adjusted)	-16.6 pts	-6.0 pts
Engine size	49cc	49cc
Rank among all models	#5356 of 5428	#4992 of 5428
Median miles at test	13,707	9,874
MOT tests analysed	1,901	40,458
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

share of each bike's MOT tests that failed on the component · lower is better

Component	Derbi GPR50-R	Piaggio NRG
Lights & signalling	26.1%	15.0%
Steering & suspension	23.5%	15.5%
Brakes	15.4%	10.2%
Tyres & wheels	4.6%	4.7%
Drive system	9.1%	0.0%
Structure & body	6.3%	2.5%
Fuel & exhaust	3.5%	3.8%

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

first-time MOT pass rate in each calendar year both bikes were tested

Test year	Derbi GPR50-R	Piaggio NRG
2011	53.4%	63.9%
2012	48.3%	63.4%
2013	49.1%	64.1%
2014	59.3%	67.4%
2015	57.0%	68.8%
2016	64.2%	68.0%
2017	65.8%	72.0%
2020	66.7%	71.8%

Each year mixes bikes of different ages, so a fleet that is getting older tends to slip.

Pass rate by mileage

first-time MOT pass rate by miles on the clock at test

Mileage	Derbi GPR50-R	Piaggio NRG
0k-10k miles	57.7%	71.3%
10k-20k miles	50.1%	60.6%
20k-30k miles	55.6%	55.7%
30k-40k miles	50.4%	57.0%

Bands with fewer than 30 tests for either bike are left out.

Derbi GPR50-R vs Piaggio NRG FAQ

answers computed from the data above · terms in the glossary

Which is more reliable, the Derbi GPR50-R or the Piaggio NRG?

The Piaggio NRG passes its MOT first time more often than the Derbi GPR50-R: 65.5% vs 53.4%, a 12.1-point lead. Adjusted for age, mileage and test class, the Piaggio NRG still comes out ahead: -16.6 points vs comparable bikes for the Derbi GPR50-R, -6.0 for the Piaggio NRG. An MOT checks roadworthiness items, not engine or gearbox internals.

What does the Derbi GPR50-R fail its MOT on most?

Lights & signalling: 26.1% of Derbi GPR50-R MOT tests failed on it, then steering & suspension (23.5%).

What does the Piaggio NRG fail its MOT on most?

Steering & suspension: 15.5% of Piaggio NRG MOT tests failed on it, then lights & signalling (15.0%).

Which holds up better at high mileage, the Derbi GPR50-R or the Piaggio NRG?

At 30k-40k miles the Piaggio NRG passes first time more often: 50.4% for the Derbi GPR50-R vs 57.0% for the Piaggio NRG.

DERBI GPR50-R 53.4% pass · 1,901 tests PIAGGIO NRG 65.5% pass · 40.5k tests

See each bike's full report (trend, mileage curve, failure breakdown and rivals) on its own page.