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Triumph Bonnevillie vs Triumph Unknown: reliability comparison

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

Triumph Bonnevillie
86%
MOT pass rate · 5 vehicles
Triumph Unknown
89%
MOT pass rate · 65,927 vehicles
Verdict: On MOT pass rate the Triumph Bonnevillie (86%) 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 Bonnevillie Triumph Unknown
MOT pass rate 86% 89% ✓
MOT failure rate 14% 11% ✓
Faults & advisories per test 0.3 ✓ 0.6
Dangerous-fault share 0% ✓ 2%
Average mileage 13,654 mi 16,601 mi
Sample size (vehicles) 5 65,927

Most common faults

Triumph Bonnevillie

  1. Stop lamp does not illuminate immediately a brake applies (1.3.1a)
  2. Front Tyre tread depth is below minimum requirements of 1.0mm (4.1.3(ii))
  3. Front Tyre valve stem damaged which could cause sudden tyre deflation (4.1.2c)
  4. Headlamp at least one does not illuminate on main beam (1.2.2a(ii))
  5. Brake lever has inadequate reserve travel (3.1.3b)
  6. Headlamp aim too high (1.6)

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 Bonnevillie (86%) and Triumph Unknown (89%) are very close — weigh the individual measures below, and remember condition depends on age, mileage and upkeep.

Full Triumph Bonnevillie 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.