Cayenne S from 2007 Tyre Dimensions??
 

I have a Cayenne from 2007 and am looking for new summer tyres (currently have winter tyres on the car) and I noticed that my current tyres are GoodYear Eagle F1 265/50/19 and the alloys are:
8JX18H2ET57
7L5.601.025.S

It seems an odd size for those alloys, 18" instead of the 19" tyres that have been fitted?)

Also any search I do suggest I would need 275/45/R19 and not 265/50/R19 and I have found receipts for 275/45/R19 tyres in the stack of paperwork that came with the car but alloys could have been changed (just like I purchased a set of 18" alloys with winter tyres last year)

What is the correct tyre size for the type of alloys I have?