W Speed rate tyres

[Zaid]

Did you know that its illegal to repair tyres that have a 'W' speed rating?
Typical thing, just put a set of new tyres 2 weeks ago, and yesterday while looking around on the car, I found a big nail in one of them... the garage told me that although it is repairable, however by law its illegal to repair them! I wonder why though...

[Roadrunner]

It's not illegal to repair them, but they can't be repaired if the puncture is outwith the main contact surface of the tyre (i.e. approximately the centre three-quarters of the tyre width) because there's too much flex on the repair patch area.