What Wears Out

Smart · fully electric · 386 inspections in 2024

Smart Forfour what wears out, measured

15.0%

fail their MOT first time. Ranks 67 of 83 electric cars tested; fleet average for electric cars is 12.0%.

The Smart Forfour fails 15.0% of first-time inspections. By 7 years that reaches 16.9%. Tyres cause 49.5% of its failures.

316passed
58failed
12passed after repair
5.7 yrsaverage age tested

Data sheet

Inspections analysed
386 first-time tests, retests excluded
First-time failure rate
15.0% (electric average 12.0%, petrol 8.2%, diesel 14.5%)
Best year
6 years old, 13.6% fail
Worst year
7 years old, 16.9% fail
Biggest cause of failure
Tyres, 49.5% of all defects
Most unusual for its class
Tyres: 2.1× the share seen on petrol and diesel cars

Versions seen in the tests

Exactly as recorded on the certificate. Counts are inspections, not cars.

  • FORFOUR386

Failure rate by age

The line to watch is the red one. Dashed lines are petrol and diesel cars of the same age, tested the same year.

    Points are hidden where fewer than 50 cars of that age were tested.

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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 the wider fleet (49.5% vs 23.7%)
    • Visibility take a bigger share of failures than on the wider fleet (19.8% vs 11.9%)

    What fails, by system

    Share of all defects that caused a failure. The dark mark is the same system on petrol and diesel cars of the same age.

    SystemShare of failing defectsThis carvs fleet
    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

    Top defects on the certificate

    Wording from the DVSA inspection manual, so it matches what a tester writes.

    1. A tyre seriously damaged17
    2. Tyre tread depth not in accordance with the requirements15
    3. Wiper blade missing or obviously not clearing the windscreen13
    4. A tyre cords visible or damaged13
    5. A suspension pin, bush or joint excessively worn10
    6. The aim of a headlamp is not within limits laid down in the requirements8

    Check before you buy

    • 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.

    What owners say about the same faults

    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 data

    Closest failure rate and age profile, different brand.

    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.

    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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    Data: DVSA anonymised MOT tests, 2024 test year, OGL v3.0. Computed by What Wears Out editorial team. Last updated .