245 x 45 x 18 or 40 ?

[napp]

I little stumped ?

I have 245 all round on my car , could I get away with 40 instead  of 45 profile ? 

as I have tried to work out just how much difference there is in height on the side wall. Did 350Z,s come out on 17s as I am shore I have seen them on older cars.

think the size on 225s is 45 so I think by going 245 x 40 there wont be much difference.

[G1en]

245/40 profile will be fine, thats what i have on mine. It will slightly lower car but wont be an issue looking at your existing pic. 

[napp]

thanks , how much more of a drop , think I worked it out about 10mm but my maths is cr@p

[G1en]

Yeah around 12mm but couple of things to note, if your going from worn out tyres to brand new you will gain half of that back with the new full 8mm tread and different tyre manufacturers can have varying widths/depths of tyre but quote the same size ie 245/40 size. But all in all, you will be fine

[Eddie_r32]

Have a look at willtheyfit, will tell you exactly what the measurements will be

[napp]

well I went for 245 x 40 x 18 all round , think it looks better with a slightly lower profile tyre , and with 245 all round I can swap back to front.