I have 195/50/15 on the back of my 5 door, and the arch is just above the tyre wall... If I drive on my own, the inner arch lip makes a mark on the tyre.. so that needs grinding off sometime. Bad bumps make it bang on the plastic liner (I think)...
I cant carry people in the back very well any more.. I can have one light person, but have to go quite slow, and you can often hear it scraping all the time... I reckon, if I got rid of that arch lip, Id be a lot better off.. I would imagine any bigger than what I have now, would cause me some bigger problems.
On the front, its -35mm (I want it going down lower sometime though) and it rubs slightly on full lock, but apart from that its fine.
Its all down the offset of the alloy at the end of the day.. Juss has 17s on his Clio with -35mm I think, and he doesnt seem to have any problems... He does have 3 doors though.. Cant see the rear arch being MUCH smaller though on the 5 door.
When I go lower on the front again, Ill go round all my arches in grind that lip off.. Im hoping this saves a lot of my problems.
There was a 5-Door Clio in Fast Car a while back, he had 17"s on and he reckoned it took him 8 hours on -35mm to get the arches right, but he cant take passengers in the back.. (according to the write up).
What a long post, but hey, it had everything I wanted to say in it!
Daz.