HARLEY-DAVIDSON XL vs TRIUMPH THUNDERBIRD

The HARLEY-DAVIDSON XL passes its MOT first time more often than the TRIUMPH THUNDERBIRD — 87.9% vs 87.8%, a 0.1-point lead.

MOT reliability, side by side

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

Metric	HARLEY-DAVIDSON XL	TRIUMPH THUNDERBIRD
First-time pass rate	87.9%	87.8%
Outright fail rate	5.3%	6.2%
Median miles at test	6,112	13,106
MOT tests analysed	18,536	56,312
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.

HARLEY-DAVIDSON XL 87.9% pass · 18.5k tests TRIUMPH THUNDERBIRD 87.8% pass · 56.3k tests

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