Triumph T21
Real ownership data from 123 UK T21 motorcycles — mileage, MOT pass rates and the faults that actually come up, taken from DVSA test records rather than opinion.
Most common T21 problems
Ranked by how often each fault appears in this model's MOT history.
| Fault | Severity | Share of faults |
|---|---|---|
| Brakes | fail | 9.3% |
| Lights and indicators | fail | 9.3% |
| Other | fail | 5.3% |
| Suspension | fail | 4.9% |
| Tyres | fail | 3.5% |
| Electrical | fail | 2.2% |
| Steering and head bearings | fail | 1.8% |
| Fluid leaks | fail | 1.8% |
Advisories (wear noted but not failed) are excluded above; the most common is suspension.
T21 mileage and reliability by year
Use this to judge whether a specific bike is high or low mileage for its age.
| Year | Examples | Median mileage | Miles/year | First-time pass |
|---|---|---|---|---|
| 1964 | 5 | 15,213 mi | 71 | 94.87% |
| 1963 | 5 | 7,301 mi | 144 | 96.67% |
| 1962 | 10 | 22,482 mi | 64 | 95.52% |
| 1961 | 15 | 28,817 mi | 142 | 95.38% |
| 1960 | 11 | 3,306 mi | 90 | 93.85% |
| 1959 | 8 | 23,644 mi | 191 | 89.29% |
| 1958 | 26 | 5,061 mi | 158 | 91.57% |
T21 questions, answered with data
What are the most common problems with the Triumph T21?
Across 123 UK examples, the most frequently recorded MOT faults are brakes (9.3% of all recorded faults), lights and indicators (9.3% of all recorded faults), other (5.3% of all recorded faults).
What is average mileage for a Triumph T21?
The median Triumph T21 in the UK has covered 12,501 miles, and typically rides about 136 miles a year. Half of all examples fall between 2,572 and 42,878 miles.
Is the Triumph T21 reliable?
93% of Triumph T21 MOT tests are passed first time, with an average of 0.36 faults recorded per test. This is measured from DVSA MOT records, not owner opinion.
Based on DVSA MOT test records for 123 Triumph T21 motorcycles registered in Great Britain and Northern Ireland. Contains public sector information licensed under the Open Government Licence v3.0.