DVSA Statistics
1978 Triumph Stag
MOT Pass Rate & Pre-MOT Checklist
There isn't much MOT data yet for the 1978 Triumph Stag (only 46 tests in our DVSA dataset), so these figures are a rough guide. We still highlight common failure items below so you can check before your MOT.
Pass Rate
Based on 46 DVSA anonymised MOT tests · About this data
Pass Rate
87%
Higher than average
Limited data available for this model; results may be less representative.
Top Failure Reasons
Common MOT failures for this model
Based on DVSA statistics from 46 recorded tests.
Pre-MOT Checklist for 1978 Triumph Stag
Based on common failure points for this model, check these items before your MOT:
- 1
Ensure engine is at operating temperature before test - take a good run beforehand
Emissions – Common fail on this model
- 2
Listen for knocks or clunks when driving over bumps - bounce each corner
Suspension – Common fail on this model
- 3
Check for excessive play in steering wheel - should be minimal free movement
Steering – Common fail on this model
How Does This Compare to Other Years?
Previous Year
1977 Triumph Stag
Based on 125 UK MOT tests
Next Year
1979 Triumph Stag
Based on 5 UK MOT tests
Compare how MOT performance varies across Triumph Stag model years.
Why Trust This Data?
Official UK Government Source
This data comes from the UK's Driver and Vehicle Standards Agency (DVSA), the official body responsible for MOT testing standards. The anonymised MOT test data is published via data.gov.uk.
Understanding the Statistics
This page is based on 46 MOT tests from the 2023 DVSA dataset. Your 1978 Triumph Stag was 45 years old when this data was collected and is now 48 years old.
Sample Size
Limited data - 46 tests (use as rough guide only)
Limitations
Statistics reflect average outcomes and don't account for maintenance history, mileage, or regional variations. Individual results will vary based on how well a vehicle has been maintained.
Do you own this car?
Check your specific vehicle for outstanding advisories or recalls. Get a personalized risk report for your exact Triumph Stag.
Frequently Asked Questions
Is a 1978 Triumph Stag likely to fail its MOT?
Based on DVSA statistics, the 1978 Triumph Stag has a 87% MOT pass rate. This is above average, indicating good reliability for a vehicle of this age.
What are the most common MOT failures on a 1978 Triumph Stag?
The most common MOT failure reasons for a 1978 Triumph Stag are: emissions levels exceed default limits, a wheel bearing with excessive play, fluid leaking excessively and likely to harm the environment or to pose a safety risk to other road users. Many of these can be checked and fixed before your test to improve your chances of passing.
How can I reduce the chance my 1978 Triumph Stag fails its MOT?
To improve your chances of passing, check the items that commonly fail on this model: emissions levels exceed default limits, a wheel bearing with excessive play, fluid leaking excessively and likely to harm the environment or to pose a safety risk to other road users. Use our pre-MOT checklist above to identify potential issues before your test. Many common failures are easy DIY fixes.
How many 1978 Triumph Stags fail their MOT?
Around 13% of 1978 Triumph Stags fail their MOT test, meaning roughly 1 in 8 don't pass first time. The most common reasons are emissions levels exceed default limits and a wheel bearing with excessive play. Pre-checking these items can significantly improve your chances.
What should I check before my 1978 Triumph Stag MOT?
Before your 1978 Triumph Stag MOT, check these commonly-failed items: emissions levels exceed default limits, a wheel bearing with excessive play, fluid leaking excessively and likely to harm the environment or to pose a safety risk to other road users. Most are visual checks you can do at home – look for worn tyres, test all lights work, and check for obvious damage or leaks.
Is the 1978 Triumph Stag reliable for MOT?
With a 87% MOT pass rate, the 1978 Triumph Stag performs above average compared to typical vehicles. This suggests good overall condition for a vehicle of this age.