B6 S4 Wheel upgrade help

[will999]

Hi all, im looking too change my rims from the standard 235 40 18 too a set of 235 35 19, but will still have a 18 spare, the handbook says a wheels need too be the same? do some qiute long runs so am worried about if I get a flat how long could I get with the spare?

all comments appretiated

[Bigsidavies]

As far as I am aware you must have the same rolling radius. So you could have an 18" and 19" on at the same time as long as the tyre profile (the 30,35,40 number) makes them both the same size overall. You will need to check that a 40/18 is the same size as a 35/19 for deffo (i have a feeling it is) and you should be ok. I would think it is a massive no no to mix rolling radius as your diff will get screwed.

Just buy a can of tyre repair stuff from halfords. I always have a can in the boot in case the doris gets a puncture - don't want her messing with jack etc. Will certainly get you to a tyre repair place.

[GDS968]

That should be fine, I currently have a 17 inch spare but am running 19inch rims, don't see this as a problem as they have the same rolling rad etc. Look at space savers they are never the same!!