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Triumph 1800 roadster vs Triumph Unknown: reliability comparison

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

Triumph 1800 roadster
92%
MOT pass rate · 2 vehicles
Triumph Unknown
89%
MOT pass rate · 65,927 vehicles
Verdict: On MOT pass rate the Triumph 1800 roadster (92%) 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 1800 roadster Triumph Unknown
MOT pass rate 92% ✓ 89%
MOT failure rate 8% ✓ 11%
Faults & advisories per test 0.9 0.6 ✓
Dangerous-fault share 0% ✓ 2%
Average mileage 7,452 mi 16,601 mi
Sample size (vehicles) 2 65,927

Most common faults

Triumph 1800 roadster

  1. Offside Rear Tyre worn close to the legal limit (4.1.E.1)
  2. Offside Front Lower Front suspension has slight movement at a wishbone pin or bush (2.5.A.1c)
  3. Offside Front Tyre worn close to the legal limit (4.1.E.1)
  4. Offside Track rod end ball joint has slight play (2.2.B.1f)
  5. Service brake: efficiency below requirements (3.7.C.1a)
  6. Front Axle king pin has slight play in pin and/or bush (2.5.A.3a)

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 1800 roadster (92%) and Triumph Unknown (89%) are very close — weigh the individual measures below, and remember condition depends on age, mileage and upkeep.

Full Triumph 1800 roadster 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.