Bmw Z4 vs Mercedes-Benz SLK
On MOT-testable defects, the Bmw Z4 (fail rate 17.1%) performed better than the Mercedes-Benz SLK (19.4%) across comparable years. The biggest divergence was suspension, where the SLK recorded failures more often.
17.1%
Z4 fail rate
19.4%
SLK fail rate
2.37pp
Difference
Side by side
| Metric | Bmw Z4 | Mercedes-Benz SLK |
|---|---|---|
| MOT tests analysed | 203,942 | 354,328 |
| Pass rate | 82.9% | 80.5% |
| Fail rate | 17.1% | 19.4% |
Where they differ
| Category | Z4 | SLK |
|---|---|---|
| Suspension | 5.7% | 9.1% |
| Lighting & signalling | 5.4% | 7.0% |
| Visibility | 3.3% | 2.6% |
| Brakes | 4.8% | 5.1% |
| Tyres | 5.1% | 5.1% |
Methodology & source. Dataset: DVSA MOT testing data (2021,2022,2023,2024,2025). Data last updated 2026-07-01. Figures reflect MOT-testable defects only — read the methodology for how these are calculated and what they don't measure.