tlg

OK, thanks for clarifying. Yeah but the efficiency ratings are 'C' at best. Compare with 205/55/16 and there are plenty of 'A's, on average cheaper too.

How do you mount a tyre that is much wider than the wheel without it bulging out unacceptably when inflated? Conversely if you try to mount a tyre much narrower than the wheel, will it seat properly?

It sounds like it's not worth the risk then, so I'll probably stay with 205/45/16. I did check what was available in the other sizes Ken mentioned but didn't see anything really compelling. Incidentally how could you fit tyres with different widths from the wheel hub anyway?

Fabia VRS Mk I original tyres are 205/45/16. This size seems to have a fairly limited selection (I'm looking for something rated 'A' on fuel economy but the best I can find is 'C'). They also seem to be quite a bit more expensive than tyres in 205/55/16. So I was thinking about fitting something in the size range 205/55/16 instead (only the rear for now, but if successful I would do the same on the front (currently KU39s in 205/45/16 with about 50% tread remaining) later). - Possible? - Legal? - Advisable? - Would any tyre centre actually agree to fit a non-original size? - Affect insurance? The only problem I'm aware of is that it would slightly offset the speedo accuracy.