Triumph Bonneville 865 vs Harley-Davidson XL

The Triumph Bonneville 865 passes its MOT first time more often than the Harley-Davidson XL: 89.2% vs 87.9%, a 1.3-point lead.

MOT reliability, side by side

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

Metric	Triumph Bonneville 865	Harley-Davidson XL
First-time pass rate	89.2%	87.9%
Outright fail rate	4.6%	5.3%
Vs comparable bikes (age & mileage adjusted)	+2.3 pts	-0.1 pts
Engine size	865cc	883cc
Rank among all models	#1212 of 5428	#1639 of 5428
Median miles at test	8,536	6,108
MOT tests analysed	5,589	18,541
Most common failure	brakes	lamps and reflectors

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	Triumph Bonneville 865	Harley-Davidson XL
Lights & signalling	1.6%	3.0%
Brakes	2.1%	0.8%
Tyres & wheels	1.1%	0.5%
Steering & suspension	0.4%	0.9%
Structure & body	0.3%	1.0%
Fuel & exhaust	0.1%	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	Triumph Bonneville 865	Harley-Davidson XL
2018	91.3%	87.1%
2019	89.5%	86.5%
2020	90.7%	89.4%
2021	92.0%	88.8%
2022	89.6%	88.5%
2023	87.8%	88.4%
2024	89.0%	87.6%
2025	90.2%	87.5%

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	Triumph Bonneville 865	Harley-Davidson XL
0k-10k miles	90.7%	89.0%
10k-20k miles	88.7%	85.5%
20k-30k miles	86.8%	85.6%
30k-40k miles	81.0%	83.6%
40k-50k miles	80.2%	82.3%

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

Triumph Bonneville 865 vs Harley-Davidson XL FAQ

answers computed from the data above · terms in the glossary

Which is more reliable, the Triumph Bonneville 865 or the Harley-Davidson XL?

The Triumph Bonneville 865 passes its MOT first time more often than the Harley-Davidson XL: 89.2% vs 87.9%, a 1.3-point lead. Adjusted for age, mileage and test class, the Triumph Bonneville 865 still comes out ahead: +2.3 points vs comparable bikes for the Triumph Bonneville 865, -0.1 for the Harley-Davidson XL. An MOT checks roadworthiness items, not engine or gearbox internals.

What does the Triumph Bonneville 865 fail its MOT on most?

Brakes: 2.1% of Triumph Bonneville 865 MOT tests failed on it, then lights & signalling (1.6%).

What does the Harley-Davidson XL fail its MOT on most?

Lights & signalling: 3.0% of Harley-Davidson XL MOT tests failed on it, then structure & body (1.0%).

Which holds up better at high mileage, the Triumph Bonneville 865 or the Harley-Davidson XL?

At 40k-50k miles the Harley-Davidson XL passes first time more often: 80.2% for the Triumph Bonneville 865 vs 82.3% for the Harley-Davidson XL.

TRIUMPH BONNEVILLE 865 89.2% pass · 5,589 tests HARLEY-DAVIDSON XL 87.9% pass · 18.5k tests

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