20” wheels, recommended for U.K. roads?

[R.A.G]

... which is strange given that the outside diameter of the wheel/tyre combination is the same ...

I was referring to the wheels, not the wheels and tyres.

 

[pdk42]

I find 18’s on the M3 to look a little lost in the arches.

The fix for that is to lower the suspension. That's the key difference in stance/looks on the P.

 

[jimbo_hippo]

The fix for that is to lower the suspension. That's the key difference in stance/looks on the P.

I find it’s the rears that’s look a bit lost. Fronts look fine. If anything, for me, it’s like the rears need to come out a bit with the factory 18”

rears too.

 

[R.A.G]

The fix for that is to lower the suspension. That's the key difference in stance/looks on the P.

So true, there’s far too much space between the wheel arch and tops of the tyres irrespective of the rim size.

 

[RichieC]

... which is strange given that the outside diameter of the wheel/tyre combination is the same ...

I think it's a bit of an optical illusion - the bigger wheel looks like it fills the arches more, even though as you say the wheel/tyre combination is the same size. Also, on the performance with 20" wheels the suspension is lowered slightly, which helps!

 

[Spacey73]

Model S85 running 21’ rims. Just had to get a rim welded from a damn pothole, just can’t bear the tiny 19’s even though they won’t get Kure day as much.

 

[Adopado]

I think it's a bit of an optical illusion - the bigger wheel looks like it fills the arches more, even though as you say the wheel/tyre combination is the same size. Also, on the performance with 20" wheels the suspension is lowered slightly, which helps!

Yes, I think perhaps the eye sees focusses on the brighter bigger rim (if it's silver) and but lets the dark tyre blend with the shadow of the wheel arch. The lowering definitely affects the stance.