The DVSA has updated its guidance for MOT testers assessing stretched tyres during the annual test with new diagrams that show correctly and incorrectly seated tyres.
Regulations say that “a tyre should not be used on a road if it’s not maintained in such condition as to be fit for the use to which the vehicle is being put”.
The DVSA say this means tyres must be fitted on suitable wheels with suitable valves, giving technicians a reason to fail stretched tyres.
Rejections might include a damaged or misaligned valve stem or an incorrectly seated tyre.
The European Tyre and Rim Technical Organisation publish a standards manual with approved rim widths for all sizes of tyre.
However, if a tyre is fitted outside of this recommendation, it does not necessarily mean the tyre will be incorrectly seated on the rim.
Whether the tyre is correctly seated will also depend of the tyre make, load carrying capacity and rim design.
In example two, the wheel rim and tyre are incompatible and there is a clear gap between the tyre bead and the wheel rim because the tyre is over-stretched.
In this instance, DVSA say the vehicle should be rejected because the tyre is incorrectly seated on the wheel rim.
Where this isn’t obvious, the nominated tester should pass and advise.
Drivers could also find that they are driving with an invalidated insurance policy if they have narrow tyres fitted on wide rims.
Are you still unsure about stretched tyres? Have you seen an extreme example? Share your comments below and send any photos to [email protected].