Triumph T21 Reliability, MOT Pass Rate & Common Faults
Free Triumph T21 car check
Is the Triumph T21 reliable? We analysed 575 real MOT tests across 115 vehicles to find out.
Got a specific Triumph T21? Enter the reg for a free check:
The Triumph T21 is above average for reliability based on real UK MOT data. Common problems include stop lamp does not illuminate immediately a brake applies, suspension has excessive stiffness in the suspension movement. and position lamp does not illuminate immediately when it is switched on. Here's everything you need to know before buying a used Triumph T21.
Triumph T21 Number Plates
Number plates registered to a Triumph T21. Click on any registration for full vehicle details — including MOT history, mileage records, previous owners and damage history.
Triumph T21 MOT Pass Rate by Year
How likely is a Triumph T21 to pass its MOT? Here's the pass rate for each registration year, newest first.
Triumph T21 Problems — What Goes Wrong?
The most common reasons a Triumph T21 fails its MOT, ranked by how often they occur. Check for these problems before you buy.
Triumph T21 Mileage — What's Normal?
How many miles does a typical Triumph T21 owner drive per year? Use this to check if a car you're looking at has suspiciously low or high mileage.
Triumph T21 MOT Data by Registration Year
Full breakdown of pass rate and mileage for each year. Use this to compare the Triumph T21 year you're looking at.
| Year | Tests | Pass Rate | Low Mi. | Typical Mi. | High Mi. |
|---|---|---|---|---|---|
| 1962 | 60 | 96.7% | 5,242 | 10,168 | 43,477 |
| 1961 | 63 | 96.8% | 2,270 | 38,417 | 57,631 |
| 1960 | 64 | 93.8% | 1,046 | 1,948 | 7,428 |
| 1958 | 86 | 91.9% | 2,185 | 3,991 | 20,252 |
How Long Does a Triumph T21 Last?
Based on 115 Triumph T21 vehicles on UK roads.
Triumph T21 Mileage Distribution
Total mileage recorded across all Triumph T21 MOT tests. If the car you're looking at is above the 75th percentile, it's done more miles than most.
Best Year to Buy a Used Triumph T21
Based on MOT pass rates across all registration years with sufficient test data.
96.8% MOT pass rate from 63 tests
91.9% MOT pass rate from 86 tests
The best year to buy a used Triumph T21 is 1961, which has the highest MOT pass rate at 96.8% across 63 tests. The 1958 model year has the lowest pass rate at 91.9% — if you're looking at one from that year, budget for potential repairs and get a thorough pre-purchase inspection.
How Does the Triumph T21 Compare?
MOT pass rates compared to similar models. Click any model for the full breakdown.
| Model | Pass Rate | Tests | Typical Mileage | Lifespan |
|---|---|---|---|---|
| Triumph T21 THIS CAR | 93.4% | 575 | 10,166 mi | 68 yrs |
| Triumph Bonneville | 90.1% | 235,206 | 7,823 mi | 53 yrs |
| Triumph Tiger | 90.6% | 196,853 | 17,026 mi | 32 yrs |
| Triumph Sprint | 87.3% | 158,613 | 21,242 mi | 33 yrs |
| Mercedes-benz AMG A 35 Premium 4MATIC ED A | 88.3% | 760 | 26,817 mi | — yrs |
Compared to the Triumph Bonneville (90.1% pass rate) and the Triumph Tiger (90.6% pass rate), the Triumph T21 outperforms both on MOT reliability.
Found a Triumph T21 you like?
Run a full vehicle history check on the specific car. See finance, stolen, write-off, mileage and MOT data for that exact vehicle.
Check a specific Triumph T21Should you buy a used Triumph T21?
The Triumph T21 has an overall MOT pass rate of 93.4% across 575 real MOT tests — comfortably above the UK average, which puts it among the more reliable models on UK roads.
The most common problems on the Triumph T21 are stop lamp does not illuminate immediately a brake applies (3 recorded failures), suspension has excessive stiffness in the suspension movement. (2), and position lamp does not illuminate immediately when it is switched on (2). These are the faults most likely to cause an MOT failure on this model, so check for them carefully on any test drive or pre-purchase inspection. Many are wear-and-tear items that can be budgeted for, but a car that's already failing on multiple fronts may signal neglected maintenance.
A typical Triumph T21 owner drives around 139 miles per year. If the car you're looking at is significantly above this, expect more wear on suspension, brakes and tyres. If it's well below, the vehicle may have been sitting unused — check for perished rubber, corroded discs and stale fluids.
In terms of longevity, most Triumph T21 models stay on UK roads for around 68 years — a strong showing that suggests solid build quality and readily available parts. If you're buying one that's already approaching that window, the data suggests it has plenty of life left provided it's been maintained.
Before committing to a purchase, we recommend running a full vehicle history check on the specific car. This will reveal any outstanding finance, stolen markers, write-off history and mileage discrepancies that the seller may not disclose — and that the MOT data alone can't tell you.