TRIUMPH T21

350cc Petrol Class 2

#381 of 5426 overall #22 of 175 TRIUMPHs #237 of 2787 other bikes

92.5%

first-time pass rate

3.9%

failed outright

13,628

median miles at test

612

MOT tests, 2005–2025

Pass rate over time

first-time pass rate by test year · 2006–2017

The T21's first-time pass rate has held steady since 2006 (91.9% → 91.4%).

Pass rate by mileage

how the T21's first-time pass rate falls with the odometer · class average 84.9%

A low-mileage T21 passes first time 92.0% of the time; by 50k that's 92.3%.

First-time pass rate by odometer reading at test, 10,000-mile bands for this model. Mileage is the strongest reliability signal. See the full curve.

What fails on a T21

failure defects by component group · advisories excluded

Component group	Defects	% of defects	vs all bikes
steering and suspension	17	30.4	0.6×
lighting and signalling	16	28.6	0.3×
brakes	12	21.4	0.3×
tyres and wheels	4	7.1	0.3×
drive system	2	3.6	0.5×
body and structure	2	3.6	0.3×
driving controls	1	1.8	0.7×
Items Not Tested	1	1.8	1.8×
fuel and exhaust	1	1.8	0.2×

Defects recorded against failed normal tests, 2005–2025, grouped by DVSA inspection section. One test can record multiple defects. "vs all bikes" is how often this model's tests record a defect in the group, as a multiple of the all-bike rate.

How rivals compare

same type, similar capacity, high test volume

On first-time pass rate the T21 beats 4 of its 4 closest rivals (SUZUKI AN400, SUZUKI DR-Z400S, YAMAHA RD350).

SUZUKI AN400 86.2% pass · 27.1k tests SUZUKI DR-Z400S 80.4% pass · 26.8k tests YAMAHA RD350 86.3% pass · 19.6k tests KAWASAKI ZXR400 73.1% pass · 14.2k tests

Rivals share this bike's type and sit within ±30% of its engine capacity, ≥ 5,000 tests. Card colour = better/worse first-time pass rate than the T21.

Pass rate by registration year

how each model-year cohort fares · registration year from first use date

Best year to buy used: 1961 (94.7% pass). Weakest: 1959 (86.0%).

First-time pass rate by the year each bike was first registered (cohorts with ≥ 50 tests). Older cohorts are survivors: the worst examples have already left the road, which tends to lift the earliest years.

TRIUMPH T21 FAQ

answers computed from the data above · terms in the glossary

Is the TRIUMPH T21 reliable?

The TRIUMPH T21 is more reliable than average for its class: 92.5% of its 612 MOT tests (2005–2025) passed first time, against a class average of 84.9%. That ranks it #381 of 5426 models.

What does a T21 fail its MOT on most?

steering and suspension — 30% of all defects recorded against failed T21 tests.

What is the best year of T21 to buy used?

By first-time pass rate, 1961-registered examples do best (94.7%) and 1959 worst (86.0%). Condition and history still trump the year.

How many miles will a T21 last?

The median T21 shows 13,628 miles at test, and examples around 50k miles still pass 92.3% of the time — mileage alone rarely kills one.