Triumph 21 MOT Pass Rate
Overall pass rate across all manufacture years, based on 264 real MOT test results. Failure rate: 6.8%.
Data from official DVSA MOT testing records
Triumph 21 MOT Reliability Overview
The Triumph 21 is a rare vehicle in the UK, with 264 MOT test results recorded in our database spanning 5 manufacture years. It has an overall MOT pass rate of 93.2% and a failure rate of 6.8%, which is well above the UK average of approximately 37%.
Based on this data, the Triumph 21 earns a "Excellent" reliability rating. The average Triumph 21 presents for MOT with approximately 28,395 miles on the clock. Manufacture year matters: 1963 models achieve the highest pass rate at 96.7%, while 1962 models have the lowest at 87.5%. This 9.2 percentage point difference suggests notable variation in build quality or component durability across production years.
The most common MOT failure for the Triumph 21 is Motorcycle lighting and signalling, affecting 3.8% of all tests. Motorcycle lighting and signalling issues are a common cause of MOT failure. Regular inspection and maintenance of these components helps ensure your vehicle passes its MOT. The second most common issue is Motorcycle tyres and wheels at 2.7%. Motorcycle steering and suspension rounds out the top three at 2.3%. Together, these top 3 failure categories account for a significant portion of all MOT failures for this model.
Top failures across all manufacture years combined. Individual year pages may show different top failures.
What Fails Most
Pass Rate by Manufacture Year
* High Fail Rate badge indicates an MOT pass rate below 65% (failure rate above 35%).
What Fails on This Car?
Click a category to see specific failure items.
View as table
| Rank | Failure Category | Rate (%) | Count |
|---|---|---|---|
| 1 | Motorcycle Lighting And Signalling | 3.8% | 10 |
| 2 | Motorcycle Steering And Suspension | 2.7% | 7 |
| 3 | Motorcycle Tyres And Wheels | 2.7% | 7 |
| 4 | Motorcycle Brakes | 2.3% | 6 |
| 5 | Motorcycle Fuel And Exhaust | 1.1% | 3 |
| 6 | Motorcycle Body And Structure | 0.8% | 2 |
| 7 | Motorcycle Drive System | 0.8% | 2 |
| 8 | Motorcycle Driving Controls | 0.4% | 1 |
Failures per 10,000 Miles
avg. 28,395 miFor every 10,000 miles driven, this shows what percentage of MOT tests fail for each category. This accounts for how far cars are actually driven, not just raw pass/fail counts.
View as table
| Category | Rate / 10K mi | Raw % | Count |
|---|---|---|---|
| Motorcycle lighting and signalling | 1.33 | 3.8% | 10 |
| Motorcycle steering and suspension | 0.93 | 2.7% | 7 |
| Motorcycle tyres and wheels | 0.93 | 2.7% | 7 |
| Motorcycle brakes | 0.80 | 2.3% | 6 |
| Motorcycle fuel and exhaust | 0.40 | 1.1% | 3 |
| Motorcycle body and structure | 0.27 | 0.8% | 2 |
| Motorcycle drive system | 0.27 | 0.8% | 2 |
| Motorcycle driving controls | 0.13 | 0.4% | 1 |
🚗 Similar Cars to Consider
Mileage at MOT
The average Triumph 21 has 28,395 miles when tested for MOT.
📊 Mileage-Adjusted Failure Rate
How often this car fails MOT relative to how much it's driven — a fairer comparison than raw pass rate.
The Triumph 21 has a mileage-adjusted failure rate of 2.39% per 10,000 miles driven. The average across all makes is 5.38%, so this model is better than average.
About Triumph 21 MOT Data
The Triumph 21 is a rare vehicle in the UK, with 264 MOT test results recorded in our database spanning 5 manufacture years. It has an overall MOT pass rate of 93.2% and a failure rate of 6.8%, which is well above the UK average of approximately 37%.
For Triumph 21 owners, these results suggest a reliable vehicle that generally passes its MOT without major issues. Focus your pre-MOT checks on motorcycle lighting and signalling and motorcycle tyres and wheels for the best chance of a first-time pass. Use our detailed year-by-year breakdown and failure analysis below to understand how your specific 21 is likely to perform.
Motorcycle lighting and signalling — 3.8% of failures
Motorcycle lighting and signalling issues account for 3.8% of MOT failures on the Triumph 21. Motorcycle lighting and signalling issues are a common cause of MOT failure. Regular inspection and maintenance of these components helps ensure your vehicle passes its MOT. Typical repair costs: £100–400. Pre-MOT check: Have this system checked during regular servicing. Look for warning signs like unusual noises, vibrations, or dashboard warning lights.
Motorcycle tyres and wheels — 2.7% of failures
Motorcycle tyres and wheels issues account for 2.7% of MOT failures on the Triumph 21. Tyre failures include tread depth below the legal minimum of 1.6mm, cuts, bulges, exposed cords, and incorrect tyre pressure. Tyres are one of the most common and easiest-to-prevent MOT failures. Typical repair costs: £50–200 per tyre. Pre-MOT check: Check tread depth with a 20p coin — if the outer band is visible, the tyre is too worn. Look for bulges, cuts, or embedded objects. Ensure all tyres match the recommended size and load rating.
Motorcycle steering and suspension — 2.3% of failures
Motorcycle steering and suspension issues account for 2.3% of MOT failures on the Triumph 21. Suspension failures typically involve worn bushes, leaking shock absorbers, broken coil springs, and damaged suspension arms. These affect ride quality, tyre wear, and road holding. Typical repair costs: £200–500. Pre-MOT check: Look for uneven tyre wear, listen for clunking over bumps, and check if the car pulls to one side. A bouncy ride suggests worn shock absorbers. Visually inspect coil springs for cracks.
Frequently Asked Questions
What is the MOT pass rate for the Triumph 21?
Based on 264 MOT tests in our database, the Triumph 21 has an overall pass rate of 93.2% (6.8% fail rate).
What are the most common MOT failures on a Triumph 21?
The top 3 reasons a Triumph 21 fails its MOT are: 1. Motorcycle lighting and signalling (3.8%), 2. Motorcycle tyres and wheels (2.7%), 3. Motorcycle steering and suspension (2.3%). Check these areas before booking your MOT.
Is the Triumph 21 reliable?
With a 6.8% MOT failure rate, the 21 is more reliable than average compared to the UK average of ~40%.
What should I check before an MOT on my Triumph 21?
Based on failure data, focus on: Motorcycle lighting and signalling (3.8%); Motorcycle tyres and wheels (2.7%); Motorcycle steering and suspension (2.3%). These are the areas most likely to cause a fail. Also check all lights, tyres (minimum 1.6mm tread), and windscreen condition — these are quick wins that apply to all cars.
Based on DVSA anonymised MOT test data (2005–2024). Crown copyright, Open Government Licence v3.0.