Skip to content

Triumph T120 bonnieville vs Triumph Unknown: reliability comparison

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

Triumph T120 bonnieville
93%
MOT pass rate · 7 vehicles
Triumph Unknown
89%
MOT pass rate · 65,927 vehicles
Verdict: On MOT pass rate the Triumph T120 bonnieville (93%) 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 T120 bonnieville Triumph Unknown
MOT pass rate 93% ✓ 89%
MOT failure rate 7% ✓ 11%
Faults & advisories per test 0.1 ✓ 0.6
Dangerous-fault share 0% ✓ 2%
Average mileage 7,421 mi 16,601 mi
Sample size (vehicles) 7 65,927

Most common faults

Triumph T120 bonnieville

  1. Wheel alignment slightly misaligned. (2.5.1)
  2. Steering control chaffing between components and not interfering with free movement of steering (2.1.2a)
  3. steering lock welded.
  4. Drive chain slightly loose (6.2.1d)
  5. Rear Wheel alignment incorrect which adversely affects the handling (2.5.1)
  6. Rear Tyre tread depth is below minimum requirements of 1.0mm (4.1.3(ii))

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 T120 bonnieville (93%) and Triumph Unknown (89%) are very close — weigh the individual measures below, and remember condition depends on age, mileage and upkeep.

Full Triumph T120 bonnieville 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.