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Triumph Stag coupe vs Triumph Unknown: reliability comparison

MOT pass rates, common faults and mileage compared from real UK MOT data.

Triumph Stag coupe
83%
MOT pass rate · 5 vehicles
Triumph Unknown
89%
MOT pass rate · 65,927 vehicles
Verdict: On MOT pass rate the Triumph Stag coupe (83%) and Triumph Unknown (89%) are very close — weigh the individual measures below, and remember condition depends on age, mileage and upkeep.

Head to head

Measure Triumph Stag coupe Triumph Unknown
MOT pass rate 83% 89% ✓
MOT failure rate 17% 11% ✓
Faults & advisories per test 1.0 0.6 ✓
Dangerous-fault share 0% ✓ 2%
Average mileage 80,648 mi 16,601 mi
Sample size (vehicles) 5 65,927

Most common faults

Triumph Stag coupe

  1. Offside Front wheel bearing has slight play (2.5.A.3c)
  2. Offside Seat belt anchorage prescribed area is corroded but not considered excessive (5.2.6)
  3. Parking brake: efficiency below requirements (3.7.B.7)
  4. Offside Steering rack gaiter deteriorated (2.2.D.2d)
  5. front and rear number plates not off the same format
  6. Offside Rear wheel bearing has slight play (2.6.2)

Triumph Unknown

  1. Exhaust noisy (8.1.1 (a))
  2. Exhaust noisy (7.1.2)
  3. Front Roller brake test indicates slight fluctuation of brake effort (3.3.A1d)
  4. COVID-19 6 MONTH EXTENSION
  5. Rear Tyre worn close to the legal limit (5.2.3 (e))
  6. Steering headbearing has slight free play (2.2.2)

Reliability FAQ

On MOT pass rate the Triumph Stag coupe (83%) and Triumph Unknown (89%) are very close — weigh the individual measures below, and remember condition depends on age, mileage and upkeep.

Full Triumph Stag coupe report Full Triumph Unknown report Most reliable cars

Pass rates are computed over completed (pass/fail) MOT tests. Reliability also depends on age, mileage and upkeep — see each model's page for the full picture.