Could someone confirm the width of the oem 17" wheels on the UK Mazda 5 sport please (not sure if other countries have different wheel widths)?

If they are 6.5J as I think they are has anyone tried fitting 225/50 tyres? All the calculators say not to use 225 45's on 6.5J rims, but that its ok to use 225 50's on 6.5j rims (though I have no idea why).

Thank you in advance for your help

Ziggy

P.s im aware of speedo issues etc etc. At the moment i'm solely concerned with the tyre fitting on the rim.