17.5%
Tyre worn close to the legal limit or worn on the edge
A tyre is worn, cut, damaged or otherwise not fit for the road. Tyres are the only thing connecting the car to the road, so this is always worth taking seriously.
SmartUsed-car reliability
How reliable is a used Smart?
At 7 years old, the average Smart fails its MOT more often than the average UK car.
MOT fail rate · 7-year-old cars
Smart17.2%
UK average16.6%
Fails more often than the average 7-year-old car (about 1 in 6 MOTs, 16.6%)
Where to start
The lowest and highest fail rates in the Smart range
The Smart models whose MOT tests at 7 years old most and least often ended in a fail.
Lowest fail rates
- 1
Smart ForTwo15.8%fail rate - 2
Smart ForFour18.5%fail rate
What actually goes wrong
What breaks on Smart cars
The most common MOT faults across the Smart range, in plain English. Models with more MOT tests count for more. The percentage is the share of MOT tests on Smart cars that recorded that defect.
16.9%
Rigid brake pipe
A rigid metal brake pipe is corroded, damaged, kinked, or leaking. These permanently fixed pipes carry pressurised brake fluid — any weakness is a serious safety concern.
MOT wording: Brake pipe corroded or covered in grease
13.4%
Tyre slightly damaged, cracking or perishing
A tyre is worn, cut, damaged or otherwise not fit for the road. Tyres are the only thing connecting the car to the road, so this is always worth taking seriously.
10.2%
Brake disc or drum
A brake disc or drum is excessively worn, scored, cracked, warped, or corroded. These are the rotating parts that the pads or shoes press against to slow the car.
MOT wording: Brake disc worn, pitted or scored, but not seriously weakened
Across all Smart models; models with more MOT tests count for more.
The whole range
Every Smart that ranks, in plain English
For each model, one number: the share of its MOT tests at 7 years old that ended in a fail. Retests count as tests. Lower is better. The UK average (about 1 in 6 MOTs, 16.6%) is shown for reference. Only models with enough MOT data at 7 years old are ranked. The rest sit just below, unranked.
2 models
Smart ForTwo
The lowest 7-year fail rate of any Smart here.
15.8%fail rate at 7 years old
Smart ForFour
Above the Smart average, and at or above the UK average.
18.5%fail rate at 7 years old
Fail rates are the share of MOT tests on 7-year-old cars ending in a fail, retests included (DVSA MOT results, 2025). UK average across all makes at the same age: 16.6%. How we count fail rates
Not directly comparable with the figures at 7 years old
Shown unranked. These models don’t have enough MOT data at 7 years old yet. They’re either too new (few cars old enough) or too old (few still on the road). Each is shown at the age with the most tests, so the percentages aren’t directly comparable to the list above.
Looking at one in particular?
Averages tell you the odds across the range. Enter a number plate to see that car’s own MOT history, its risk rating, and what’s likely to need attention.