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Triumph Tr3b vs Triumph Unknown: reliability comparison

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

Triumph Tr3b
83%
MOT pass rate · 6 vehicles
Triumph Unknown
89%
MOT pass rate · 65,927 vehicles
Verdict: On MOT pass rate the Triumph Tr3b (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 Tr3b Triumph Unknown
MOT pass rate 83% 89% ✓
MOT failure rate 17% 11% ✓
Faults & advisories per test 0.9 0.6 ✓
Dangerous-fault share 0% ✓ 2%
Average mileage 44,515 mi 16,601 mi
Sample size (vehicles) 6 65,927

Most common faults

Triumph Tr3b

  1. Nearside Front Outer Track rod end ball joint dust cover excessively deteriorated so that it no longer prevents the ingress of dirt (2.2.C.1c)
  2. Nearside Rear Stop lamp not working (1.2.1b)
  3. Offside Front Steering pivot point has excessive play Idler arm (2.2.B.1g)
  4. Offside Rear Stop lamp not working (1.2.1b)
  5. Steering system excessively tight From right hand lock to centre (2.2.D.1)
  6. Front Front wheel bearing has slight play (2.5.A.3c)

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 Tr3b (83%) and Triumph Unknown (89%) are very close — weigh the individual measures below, and remember condition depends on age, mileage and upkeep.

Full Triumph Tr3b 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.