Tyre Size- 18" > 19" ???

[TinTin1201]

Hi guys,

i gonna be swapping my Standard B5 RS4 18" alloys for a set of 19" B7 Rs4 alloys soon(when i get the tyre's)

#Question is about Tyre Size- My 18" tyre size is- 255/35/18"- the original tyre size for the 19" is- 255/35/19".(Audi B7 RS4)
Now i was going to stick with this size for the 19"..... until a mate mentioned Rolling Radious( he states if you go up an alloy size you must come down a tyre size ,or the speed clock-,fuel consumsion etc,...will be out ?
He thinks the tyres should be 255/30/19"

Thoughts on this before i buy the tyres!!

[jimbo1234567]

265 or 275/30 19 goodyears are the best value and cheapest place is camskills

[davs4]

^^^^^^^^^^^Second that^^^^^^^^^^^^^^^^

[Virdee Autos]

Or 255/30/19 if you want the rolling radius to be exactly the same. But a dearer tyre to biy than the 265/275