Triumph Stag — MOT statistics 2024

The Triumph Stag failed 18.94% of 1,267 first MOT attempts in 2024 ("first-time", excluding retests). Adjusted for the age of the fleet, its initial-failure ratio is 46.3 (100 = expected for its age profile). This car fails its MOT about 54% less often than expected for its age. Small sample — treat with care.

Age-adjusted peer: Lexus UX (index 46.3) — the two published results are 0.0 index points apart.

Triumph Stag common problems: what actually fails the MOT

Lamps, reflectors and electrical equipment are well below the reference at 19.0 per 100 tests, against 29.5 per 100 tests across UK vehicles of the same ages.

higher bar = fails more oftenrate per 100 tests

family vs national — matched to UK vehicles of the same ages — top component groups, per 100 tests. Legend: This family · National avg. Combined labels: family / national average. A gap here reflects how these vehicles are driven, used and maintained as well as how they were built — an MOT defect is a test outcome, not a breakdown.

Named defects ranked by how much more often they appear than the national average — not by raw rate.

Triumph Stag MOT advisories: what gets flagged

Suspension is highest at 30.2 per 100 tests; Body & structure are lowest at 5.3 per 100 tests — the gap is 24.9 per 100 tests.

higher bar = flagged more oftenadvisory items per 100 initial tests

Advisories are wear the tester noted but didn't fail — what will need money soon.

If a car like this fails, does it fail again?

A failure rate does not say whether a failure is a one-off or the start of something. This follows the same vehicles into their next ordinary MOT a year later — retests after a repair are excluded, because they follow a failure by definition. 2019-2024.

A failed test raises next year's chance of failing again by 8.4 percentage points. The failure most likely to come back is body, chassis, structure — 25.4% of those vehicles fail again next year. Some of this is the vehicle and some is the owner: a car that was let go once tends to be let go again. One caveat: a car that fails may be sold or scrapped rather than tested again, so these figures describe the vehicles that came back.

Adjusted for how much these are actually driven

The headline index adjusts for the fleet's age. Wear, though, follows mileage: a three-year-old taxi and a three-year-old garage queen sit in the same age band. These two rows compare every car with vehicles of the same age, and then with vehicles of the same age and the same annual mileage, 2019-2024, on 8,591 tests. Both stand on the six-year corpus so they are measured on identical data — compare them with each other, not with the headline index above, which is measured on 2024 alone.

Mileage matters here: matching on how much these are driven moves the figure by 12.1 points — this fleet is driven less than the vehicles it is measured against, so the age-only view flatters it — but it does not change which side of normal the car sits on. One limit to keep in mind: mileage is partly a result of how often a car breaks down — one that spends weeks in the workshop covers fewer miles — so the mileage-matched figure can understate a real weakness. Tests with no usable odometer reading are left out of it.

How does the Triumph Stag perform as it gets older?

The Stag at age 20 is well below the reference at 19.0%, against 41.0% for all vehicles of the same age.

higher = larger sharecompare shares in percentage points

Chart axes: car age, years · failure-rate scale 0–47%.

Takeaway: solid line: this family; dashed: all cars.

How dangerous are Triumph Stag MOT failures?

Dangerous defects are well below the reference at 4.6 per 100 tests, against 11.2 per 100 tests nationally.

higher bar = fails more oftenrate per 100 tests

Chart values: Minor 9.9 · Major 52.3 · Dangerous 4.5.

Per 100 tests on this family. National average: Minor 14.2 · Major 52.8 · Dangerous 11.2 per 100.

Does the month of a Triumph Stag MOT matter?

Feb is highest at 27.8%; Oct is lowest at 17.7% — the gap is 10.1 percentage points.

higher = larger sharecompare shares in percentage points

Chart scale: 16%–33%.

bars: Triumph Stag · dashed: all class-4 cars

Takeaway: the spread between best and worst month is 10.1 percentage points — noticeable seasonality. Seasonality partly reflects registration-date clustering, not weather.

Before reading the shape: most of it is not about cars. Britain changes its registration plates twice a year, and 18.9% of these cars were first registered in March with another17.1% in September — 36% in two months against the 17% an even spread would give. An MOT falls due three years after first registration, so the buying calendar becomes the testing calendar. That shapes how many cars are tested each month — not how often they fail: the busiest months here are not the worst ones, so read the failure line on its own and the volume behind it separately.

Triumph Stag average mileage by age

At age 20+, the middle half of Stags runs from 23,406 miles to 79,718 miles, against 56,208 miles as the median.

further right = more milesmedian is the typical car; band is p25–p75

Does high mileage mean more Triumph Stag MOT failures at the same age?

Within the same age group, split by odometer (2024 MOTs), so this separates wear from age: at ages 15+, 20.8% of those with under 40,000 miles failed first time versus 18.7% of those with 70,000–100,000 miles.No clear mileage gap inside this age group, among cars still being tested.

line: median · band: middle half of the fleet (p25–p75)

A typical 20+-year-old Stag has ~56,208 miles on the clock. Much more — ask why; much less — check for gaps in the MOT history.

Where in Britain the Triumph Stag fails its MOT most

London W area is highest at 53.1%; Southampton area is lowest at 10.8% — the gap is 42.3 percentage points.

higher = larger sharecompare shares in percentage points

Toughest areas	% failing	vs model overall
London W (W)	53.08%	+31.5 pp
Medway (ME)	41.73%	+20.2 pp
Swindon (SN)	37.72%	+16.2 pp
Portsmouth (PO)	33.07%	+11.5 pp
Bristol (BS)	29.14%	+7.6 pp

Easiest areas	% failing	vs model overall
Southampton (SO)	10.8%	-10.7 pp
Sheffield (S)	14.65%	-6.9 pp

Every dot is a postcode area — size = how many were tested there, colour = share failing. These figures are not age-adjusted: coastal and rural areas often run older fleets and salted roads, so higher raw fail rates do not automatically mean a worse local stock of this model.

Map labels: Scotland · N. England · Wales · London · S. West. Colour scale: 11%–42% failing.

Triumph Stag faults that come together

Body & structure + Seatbelts & SRS stand out at 8.18×, against 1.00× if the faults were independent.

above 1.0× = more than expectedbelow 1.0× = less

Defects in «Body, chassis, structure» and «Seat belts and supplementary restraint systems» appear together 8.18× more often than chance (21 co-occurrences in the same test; 78 pairs compared).

Lift = how many times more often both groups appear on the same test than if independent. A pair is listed from 5 tests with both faults; the lift is shown from 20, and called above chance only when its 95% interval excludes 1 (see rough estimates).

Triumph Stag MOT repair costs

The MOT-failure repair budget per test runs from £61.85 to £117.51, against £54.85 for the test itself.

bigger number = costs morepounds per test, MOT-failing faults only

Multiply how often each component fails on this model by what that repair usually costs, and you get the amount an owner should expect to budget per test for MOT-failing faults only — roughly £62 to £118, on top of the test fee itself. It is a budgeting figure, not a quote: the spread between a set of pads and a set of discs is most of the range.

Prices are modal quotes from a hand-kept catalogue of published UK garage guides — we do not scrape the booking sites, their terms forbid it, so this list is short and updated by hand with a source and date against each line. Each line prices one typical repair in that group, not a full remedy, and only groups our catalogue actually covers are counted. The contrast worth noticing is the second card: the legal maximum for the test has been £54.85 since 2010, while the repairs it uncovers have followed inflation the whole time.

For scale from a different direction: Warrantywise, which sees used-car warranty claims rather than test failures, puts the average claim at £2,052 across the ten highest-claim models it ranks and £539 for Honda, the lowest-claim make in its index (Warrantywise index 2026, 1.6 million claims, cars aged 3–15). Those sit an order of magnitude above the figures in this table, and the gap is the point: a warranty claim is a gearbox or an engine, which almost never fails an MOT, while the faults that do fail one are corrosion, lamps and tyres, which no warranty pays for. The two numbers answer different questions and neither replaces the other.

Triumph Stag rust problems: where they corrode

Age-standardised corrosion susceptibility is well below the reference at <0.1×, against 1.00× for the national age-standardised rate.

above 1.0× = rusts more than averagebelow 1.0× = rusts less

This Triumph Stag virtually never fails on corrosion once age is held constant, and its owners live in areas that are gentler than most for the models we publish.

Corrosion is the one failure mode that is as much about geography as about the car. We keep the two apart on purpose: a model can look rusty simply because it is popular in Scotland, and a model can look clean simply because it is bought in Surrey. Blending them into a single score would hide which of the two is doing the work.

Exposure is this model's tests weighted by an area corrosion index built from frost days, salt load and distance to the coast — the composite validated at r = 0.42 against corrosion defects we actually record. It is published as a rank, not a raw score, because every mainstream model skews towards low-corrosion areas for the simple reason that most of Britain's cars are in the south. Susceptibility is standardised to the national age profile, so an old fleet does not get labelled a rusty model.

Does a Triumph Stag advisory become a failure?

Suspension is highest at 11.1%; Noise, emissions and leaks are lowest at 4.6% — the gap is 6.5 percentage points.

higher = more likelypercentage is the observed transition probability

This is the question an advisory note actually raises, and it needs six years of test history to answer. We followed the same vehicles from one MOT to the next across 2019–2024 and measured how often a component that was merely advised came back as a genuine failure at the next test.

Read it as a budgeting horizon, not a prophecy: the most likely component above turns into a failure for about 11 in 100 cars, and the median gap is 12.3 months and roughly 346 miles. The rest were repaired, sold, scrapped, or simply held. Rows with fewer than 500 tracked advisories are not shown.

What will fail next on a Triumph Stag?

Lamps, reflectors and electrical equipment after a failure at age 20+ are highest at 15.2%; Visibility after a passed at age 20+ is lowest at 3.5% — the gap is 11.7 percentage points.

higher = more likelypercentage is the observed transition probability

The same chains, cut differently: given a car's age and how its last test went, which component most often causes trouble at the following one.

The pattern that repeats across every family: a failure at one test roughly doubles the chance of a failure on the same component at the next one, and an advisory sits about half-way between a clean pass and a failure. Age bands in years; probabilities are per car, not per defect item.

Triumph Stag ownership: what six years of MOTs show

The ten-day re-test pass rate is highest at 64.5%; The later re-test pass rate is lowest at 9.9% — the gap is 54.6 percentage points.

higher = larger sharecompare shares in percentage points

Failing is usually a same-week event, not a disaster. Of 1,266 failures followed through to their re-test, 25.67% were repaired and passed the same day and 64.45% within ten days; the median gap is 3 days. 3,674 defect items were cleared in the process.

Per mile driven, not per year. Dividing failures by the miles that actually went onto the odometers between consecutive tests gives 1.734 failures per 10,000 miles, on a median of 418 miles a year across 1,973 chains. This is the number to compare between models — an annual rate quietly rewards cars that barely leave the drive.

Two populations hide inside one model. 55% of these cars strung together three or more tests with nothing recorded at all, while 17.05% carried the same advisory three times or more — the same fault, noted, ignored, noted again. When you buy used you are buying one of those two histories, and the MOT record shows which.

Odometer anomalies: 1.546% of 2,005 chains show a reading lower than the previous test, with a median drop of 9,950 miles. We call this an anomaly and not fraud on purpose — instrument swaps, imports, unit mix-ups and keying errors all land in the same bucket. Obvious typos (drops under 100 miles or over 90% of the reading) are already excluded.

Triumph Stag MOT: quick answers

Triumph Stag MOT Risk Index is well below the reference at 46.3, against 100 for a car with the same age profile.

below 100 is betterabove 100 is worse100 = normal for this model at that age

What is the Triumph Stag first-time MOT pass rate?

81.06% of first attempts passed in 2024 (1,267 tests). This is the first-time figure: retests after repair are excluded. Basis: first-time, excluding retests.

Why does this number differ from other sites?

Other sites often report a pass rate that includes retests or counts all attempts. Our 18.94% figure is the first-time initial failure rate, using 1,267 primary tests as the denominator (first-time, excluding retests). The age-adjusted MOT initial-failure ratio 46.3 is shown separately because raw rates compare fleet age as well as cars.

Compare the Triumph Stag with other cars

Nissan 200 is highest at 47.0; Audi RS6 is lowest at 45.9 — the gap is 1.1 points.

below 100 is betterabove 100 is worse100 = normal for this model at that age

Similar risk

Lexus UX (index 46.3)Audi RS6 (index 45.9)Nissan 200 (index 47.0)

Same size class

how DS DS compareshow Daihatsu Copen compareshow BMW M6 compares

By area

Triumph Stag MOT failure rate by postcode area

By failure group

Triumph Stag body, chassis and structure failuresTriumph Stag brakes failuresTriumph Stag lamps, reflectors and electrics failuresTriumph Stag noise, emissions and leaks failuresTriumph Stag seat belts and airbags failuresTriumph Stag steering failuresTriumph Stag suspension failuresTriumph Stag tyres failuresTriumph Stag visibility failures