FIGURE 1 // WHERE IT WEARSSmart Forfour
Top three failure systems, annotated from 58 failed first-time tests. Arrows point to where the defect is found on the car.
A Smart Forfour's brakes barely fail; its tyres pick up the bill
386 inspections in a single year make the FORFOUR a modestly documented electric car in the data. Tyres cause 49.5% of its failures; tyres take 2.1× the share they take on petrol and diesel cars of the same age.
First-time test findings
The five-year vs seven-year picture
AT FIVE YEARS OLD16.6%
FORFOUR failure rate. Petrol cars of the same age fail 10.7%.
AT SEVEN YEARS OLD16.9%
FORFOUR failure rate, against 14.9% for petrol.
The Smart Forfour fails 15.0% of first-time inspections. By 7 years that reaches 16.9%. Tyres cause 49.5% of its failures.
FIGURE 2 // TYRE SECTION17 certificates in 2024
The tyre that wears from the inside
Tyres take 49.5% of the defects that fail this car, 2.1× the share seen on petrol and diesel cars of the same age. The most common item in that group is "A tyre seriously damaged", recorded 17 times in 2024.
SECTION // TYRES CONCENTRATIONYear 5 crossover
Where the curve bends
The crossover with petrol happens around year 5. From there the FORFOUR's failure rate climbs faster than the petrol fleet, and the defect list explains why.
Source: DVSA MOT defect items, 2024 test year.
What to check
Check tyre age and tread across the full width, inner edge included. Electric cars wear tyres faster; a cheap mismatched set on a used car tells you how it was run. Trivial to fix, but a car advertised with worn wipers and a fresh failure certificate tells you how it was maintained. Have the suspension joints, bushes and springs checked on a lift. On this car it is a leading cause of failure and it is not visible from the outside. Check headlamp aim and every lamp before the test. It is the cheapest failure on the list and the easiest to avoid. Ask for the full MOT history by registration on the free DVSA service: advisories are next year's failures.
3 inspection points:
✓ Tyre inner-edge wear and age
✓ Wipers and washers
✓ Suspension joints and bushes on a lift
FIGURE 3 // FAILURE RATE BY AGEvs petrol, diesel and all electric cars
Points hidden where fewer than 50 cars of that age were tested. Dashed lines are the same-age petrol and diesel fleets.
Data sheet
- Inspections
- 386
- Passed
- 316
- Failed
- 58
- Passed after repair
- 12
- Failure rate
- 15.0% (all EV 12.0%)
- Average age
- 5.7 years
- Best year
- 6 yrs · 13.6%
- Worst year
- 7 yrs · 16.9%
- Top cause
- Tyres 49.5%
TABLE 1 // WHAT FAILS, BY SYSTEMshare of failing defects
| System | This car (mark = petrol/diesel) | Share | vs petrol/diesel |
|---|---|---|---|
| Tyres | 49.5% | 2.1× more | |
| Suspension | 11.7% | in line | |
| Brakes | 3.6% | 5.2× less | |
| Visibility | 19.8% | 1.7× more | |
| Lighting | 13.5% | in line | |
| Steering | 0.9% | 3.4× less | |
| Body | 0.0% | in line |
TABLE 2 // TOP DEFECTS ON THE CERTIFICATE
- A tyre seriously damaged17
- Tyre tread depth not in accordance with the requirements15
- Wiper blade missing or obviously not clearing the windscreen13
- A tyre cords visible or damaged13
- A suspension pin, bush or joint excessively worn10
- The aim of a headlamp is not within limits laid down in the requirements8
Wording as printed by the tester, from the DVSA inspection manual.
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Where it holds up
- Brakes fail less often than on petrol and diesel cars (3.6% of defects vs 18.7%)
- Steering fail less often than on petrol and diesel cars (0.9% of defects vs 3.1%)
- Body fail less often than on petrol and diesel cars (0.0% of defects vs 4.1%)
Where it fails
- Tyres take a bigger share of failures than on petrol and diesel cars of the same age (49.5% vs 23.7%)
- Visibility take a bigger share of failures than on petrol and diesel cars of the same age (19.8% vs 11.9%)
VERSIONS SEEN IN THE TESTSas recorded
- FORFOUR386
OWNER REPORTS // MATCHED TO RECORDED DEFECTS0 read · 0 matched
No owner discussion has been matched to this car's recorded defects yet. Reports are re-collected every quarter; the figures on this page do not depend on them.
Summaries written by us, never quotes; every entry links to its source. Owner reports have no denominator and never feed the failure rate.
SIMILAR CARS IN THE DATAclosest rate and age, other brands
Nissan Leaf15.4% fail · 49,764 testsTesla Model X18.3% fail · 6,208 testsMercedes-Benz Vito14.3% fail · 126 testsCitroen Berlingo18.5% fail · 216 tests
OTHER SMART ELECTRIC CARS
Three things the data shows
- 386 inspections in 2024 make this one of the adequately-documented electric cars in the data.
- Tyres take 2.1× the share of failures they take on petrol and diesel cars of the same age.
- Failure rate rises from 13.6% at 6 years to 16.9% at 7: a gentle ageing curve.
LIMITS // WHAT THE INSPECTION DOES NOT TELL YOU
No battery health, no motor, no charging performance. The test covers brakes, suspension, steering, tyres, lights, visibility and structure. A car with a badly degraded battery passes as long as it stops and steers. Read this page as evidence about the chassis, not the powertrain. Cars are tested from their third year, so the newest model years are missing; every figure carries its sample size for that reason. Full methodology.
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