Harley-Davidson Flhxs Street Glide SP 1868 21 vs Triumph Rocket Iii

The Harley-Davidson Flhxs Street Glide SP 1868 21 passes its MOT first time more often than the Triumph Rocket Iii: 95.1% vs 88.3%, a 6.8-point lead.

MOT reliability, side by side

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

Metric	Harley-Davidson Flhxs Street Glide SP 1868 21	Triumph Rocket Iii
First-time pass rate	95.1%	88.3%
Outright fail rate	2.2%	6.1%
Vs comparable bikes (age & mileage adjusted)	+6.9 pts	+2.7 pts
Engine size	1,868cc	2,294cc
Median miles at test	8,153	13,110
MOT tests analysed	185	15,488
Most common failure	brakes	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.

Pass rate by mileage

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

Mileage	Harley-Davidson Flhxs Street Glide SP 1868 21	Triumph Rocket Iii
0k-10k miles	95.7%	89.2%
10k-20k miles	92.7%	88.6%

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

HARLEY-DAVIDSON FLHXS STREET GLIDE SP 1868 21 95.1% pass · 185 tests TRIUMPH ROCKET III 88.3% pass · 15.5k tests

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