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Triumph Bike custom vs Triumph Unknown: reliability comparison

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

Triumph Bike custom
83%
MOT pass rate · 1 vehicles
Triumph Unknown
89%
MOT pass rate · 65,927 vehicles
Verdict: On MOT pass rate the Triumph Bike custom (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 Bike custom Triumph Unknown
MOT pass rate 83% 89% ✓
MOT failure rate 17% 11% ✓
Faults & advisories per test 1.5 0.6 ✓
Dangerous-fault share 0% ✓ 2%
Average mileage 168 mi 16,601 mi
Sample size (vehicles) 1 65,927

Most common faults

Triumph Bike custom

  1. Front Steering movement slightly stiff (2.2.1b)
  2. Front mudguard missing
  3. Two grooves visible in rear tyre tread.
  4. Exhaust noisy (7.1.2)
  5. Rear Rear position lamp does not illuminate immediately when it is switched on (1.1.3a)
  6. Rear Rear reflector on motorcycle missing (1.4.1)

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 Bike custom (83%) and Triumph Unknown (89%) are very close — weigh the individual measures below, and remember condition depends on age, mileage and upkeep.

Full Triumph Bike custom 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.