Triumph Twenty One Reliability, MOT Pass Rate & Common Faults
Free Triumph Twenty One car check
Is the Triumph Twenty One reliable? We analysed 847 real MOT tests across 163 vehicles to find out.
Got a specific Triumph Twenty One? Enter the reg for a free check:
The Triumph Twenty One is above average for reliability based on real UK MOT data. Common problems include tyre has a cut in excess of the requirements deep enough to reach the ply or cords, steering headbearing has excessive free play and throttle operating incorrectly. Here's everything you need to know before buying a used Triumph Twenty One.
Triumph Twenty One Number Plates
Number plates registered to a Triumph Twenty One. Click on any registration for full vehicle details — including MOT history, mileage records, previous owners and damage history.
Triumph Twenty One MOT Pass Rate by Year
How likely is a Triumph Twenty One to pass its MOT? Here's the pass rate for each registration year, newest first.
Triumph Twenty One Problems — What Goes Wrong?
The most common reasons a Triumph Twenty One fails its MOT, ranked by how often they occur. Check for these problems before you buy.
Triumph Twenty One Mileage — What's Normal?
How many miles does a typical Triumph Twenty One owner drive per year? Use this to check if a car you're looking at has suspiciously low or high mileage.
Triumph Twenty One MOT Data by Registration Year
Full breakdown of pass rate and mileage for each year. Use this to compare the Triumph Twenty One year you're looking at.
| Year | Tests | Pass Rate | Low Mi. | Typical Mi. | High Mi. |
|---|---|---|---|---|---|
| 1965 | 73 | 97.3% | 6,918 | 19,334 | 45,629 |
| 1964 | 94 | 90.4% | 17,679 | 44,320 | 56,642 |
| 1963 | 90 | 92.2% | 4,207 | 5,656 | 16,384 |
| 1962 | 79 | 92.4% | 1,881 | 6,999 | 16,798 |
| 1961 | 81 | 91.4% | 1,634 | 7,874 | 32,851 |
| 1960 | 56 | 98.2% | 496 | 3,470 | 37,815 |
| 1958 | 51 | 94.1% | 2,588 | 8,648 | 20,746 |
How Long Does a Triumph Twenty One Last?
Based on 163 Triumph Twenty One vehicles on UK roads.
Triumph Twenty One Mileage Distribution
Total mileage recorded across all Triumph Twenty One 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 Twenty One
Based on MOT pass rates across all registration years with sufficient test data.
98.2% MOT pass rate from 56 tests
90.4% MOT pass rate from 94 tests
The best year to buy a used Triumph Twenty One is 1960, which has the highest MOT pass rate at 98.2% across 56 tests. The 1964 model year has the lowest pass rate at 90.4% — if you're looking at one from that year, budget for potential repairs and get a thorough pre-purchase inspection.
How Does the Triumph Twenty One Compare?
MOT pass rates compared to similar models. Click any model for the full breakdown.
| Model | Pass Rate | Tests | Typical Mileage | Lifespan |
|---|---|---|---|---|
| Triumph Twenty One THIS CAR | 92.6% | 847 | 16,179 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 A 200 AMG Ln Prem + Night ED A | 91% | 546 | 21,257 mi | — yrs |
Compared to the Triumph Bonneville (90.1% pass rate) and the Triumph Tiger (90.6% pass rate), the Triumph Twenty One outperforms both on MOT reliability.
Found a Triumph Twenty One 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 Twenty OneShould you buy a used Triumph Twenty One?
The Triumph Twenty One has an overall MOT pass rate of 92.6% across 847 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 Twenty One are tyre has a cut in excess of the requirements deep enough to reach the ply or cords (4 recorded failures), steering headbearing has excessive free play (4), and throttle operating incorrectly (3). 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 Twenty One owner drives around 86 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 Twenty One 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.