Can anybody give chapter & verse on front cycle wing tyre cover requirements.

I'm aware of the just forward of the foremost part of the alloy wheel at the front and just below the horizontal centreline at the back..

However I'd like to know what, if any the side coverage needs to be - or does the cycle wing simply need to cast a vertical shadow over the wheel, ie have virtually no sides to it? (but extend to cover the tyre on both sides)

John