Harley-Davidson XL 883 N Iron 17 vs Triumph Bonneville

The Harley-Davidson XL 883 N Iron 17 passes its MOT first time more often than the Triumph Bonneville: 90.1% vs 89.0%, a 1.1-point lead.

MOT reliability, side by side

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

Metric	Harley-Davidson XL 883 N Iron 17	Triumph Bonneville
First-time pass rate	90.1%	89.0%
Outright fail rate	4.6%	5.0%
Vs comparable bikes (age & mileage adjusted)	+0.6 pts	+1.6 pts
Engine size	883cc	865cc
Rank among all models	#921 of 5428	#1269 of 5428
Median miles at test	4,976	7,619
MOT tests analysed	3,806	195,256
Most common failure	lamps and reflectors	brakes

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	Harley-Davidson XL 883 N Iron 17	Triumph Bonneville
Lights & signalling	2.6%	1.9%
Brakes	0.8%	1.9%
Tyres & wheels	0.4%	1.1%
Steering & suspension	0.7%	0.7%
Structure & body	0.8%	0.5%
Fuel & exhaust	0%	0.3%
Drive system	0%	0.1%

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	Harley-Davidson XL 883 N Iron 17	Triumph Bonneville
2019	93.4%	88.9%
2020	92.8%	91.1%
2021	90.0%	89.6%
2022	91.2%	89.4%
2023	88.3%	90.1%
2024	89.1%	90.6%
2025	87.7%	91.0%

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	Harley-Davidson XL 883 N Iron 17	Triumph Bonneville
0k-10k miles	90.3%	90.6%
10k-20k miles	85.9%	86.8%
20k-30k miles	83.2%	85.1%

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

Harley-Davidson XL 883 N Iron 17 vs Triumph Bonneville FAQ

answers computed from the data above · terms in the glossary

Which is more reliable, the Harley-Davidson XL 883 N Iron 17 or the Triumph Bonneville?

The Harley-Davidson XL 883 N Iron 17 passes its MOT first time more often than the Triumph Bonneville: 90.1% vs 89.0%, a 1.1-point lead. Adjusted for age, mileage and test class, the Triumph Bonneville still comes out ahead: +0.6 points vs comparable bikes for the Harley-Davidson XL 883 N Iron 17, +1.6 for the Triumph Bonneville. An MOT checks roadworthiness items, not engine or gearbox internals.

What does the Harley-Davidson XL 883 N Iron 17 fail its MOT on most?

Lights & signalling: 2.6% of Harley-Davidson XL 883 N Iron 17 MOT tests failed on it, then brakes (0.8%).

What does the Triumph Bonneville fail its MOT on most?

Lights & signalling: 1.9% of Triumph Bonneville MOT tests failed on it, then brakes (1.9%).

Which holds up better at high mileage, the Harley-Davidson XL 883 N Iron 17 or the Triumph Bonneville?

At 20k-30k miles the Triumph Bonneville passes first time more often: 83.2% for the Harley-Davidson XL 883 N Iron 17 vs 85.1% for the Triumph Bonneville.

HARLEY-DAVIDSON XL 883 N IRON 17 90.1% pass · 3,806 tests TRIUMPH BONNEVILLE 89.0% pass · 195k tests

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