Triumph Bonneville Bobber (2021)

229 real MOT outcomes analysed • 84.2% first-time pass rate

2021 Triumph Bonneville Bobber

CarHunch analysed 229 real MOT records for the 2021 Triumph Bonneville Bobber. This breakdown of actual test outcomes — pass rates, defect profiles, mileage data — isn't published anywhere else.

The 2021 Triumph Bonneville Bobber passes its MOT at 84.2%, which is a solid 4.2 percentage points above the UK average—suggesting this bike is genuinely reliable out of the box. Dangerous defects are rare at just 1.8%, so safety concerns are minimal for potential buyers.

At just 3,490 miles median mileage, these bikes are still relatively young and barely run-in, which explains the low failure rate of 0.16 per vehicle. The 0.4 advisories per bike indicate minor wear items rather than serious issues, so focus your pre-purchase inspection on service history and whether the previous owner actually used the warranty rather than worrying about lurking defects.

Average reliability 4.2% above UK average
84.2%
pass MOT first time
UK average: ~80%
3,490
typical mileage
1,794–5,349 middle half
1.8%
ever had a dangerous defect
recorded at any MOT
0.16
avg MOT failures per car
over 1.8 tests on record

What to check before buying a 2021 Triumph Bonneville Bobber

Practical pre-purchase checks for this age and model.

  • 📋 Check the full MOT history. Look for recurring advisories — slow-building issues like corrosion or brake wear patterns show up years before they become failures. Enter the reg below for a full AI analysis.
  • 🔍 Inspect for corrosion in person. Brake pipes, sills, subframes, and chassis legs. Surface rust is normal at this age; structural rust is a serious problem that's expensive to fix and can fail an MOT.
  • 🛞 Check tyres and brakes. The most common advisory items at this age. Budget for replacement if they're near the limit — factor this into your offer price.
  • 📄 Run an HPI check. The MOT history won't show outstanding finance, insurance write-offs, or stolen status — an HPI check will.

Before you buy a Triumph Bonneville Bobber

MOT history is one piece of the puzzle. These checks can reveal what CarHunch can't.

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Pass Rate by Fuel Type

Fuel type Vehicles Pass rate Avg failures
Petrol (99%) 227 84% 0.16
Other (1%) 2 100% 0

Mileage Distribution

Most 2021 Triumph Bonneville Bobber vehicles sit in the blue band. If the car you're looking at is outside it, it's either unusually low or high mileage for its age.

1,794
low mileage
3,490
typical
5,349
high mileage

Half of all 2021 Triumph Bonneville Bobber vehicles fall between 1,794 and 5,349 miles.

MOT History Averages

1.8
Avg MOT tests per vehicle
0.16
Avg failures per vehicle
0.4
Avg advisories per vehicle

Found a specific Triumph Bonneville Bobber?

Enter the reg to see its individual MOT history, AI Hunches, and how it compares to this cohort.

UK

Other model years — Triumph Bonneville Bobber:

2022 2023 2024 2025