18" wheel question

[Mark]

I want to change my 205/45-17 tyres to 215/35-18. I have the 35mm H&R springs.
My question is, will the space between the tyre and the car become bigger or smaller if you compare to the original tyre size?

Thank you

[PlymTom]

I've changed my 205/55-16 to 215/35-18 on standard springs and its made the arch gap a lot bigger. So I'm guessing it will be a tiny touch larger. But don't take me on that.

[cyclone]

The overall diameter of the 18" setup is less than 1/2 inch shorter (Plytom's is worse his is almost 1" shorter going from the 16" wheel).
Even though the overall tire diameter is shorter opening the tire gap. The 18"rim is bigger which visually closes it up making the gap actually look smaller than the 17" setup

[Toxic]

have a look at the tyre calculator: http://www.etyres.co.uk/tyre-size-calculator