Hi guys, was wondering if anyone could tell me for sure what I should do...

I have a full set of 195/65R15 snow tyres on my 57 Plate Impreza, But last night after going for a blast down the road in the snow, I came out this morning to discover a flat tyre, a rusty 13mm bolt through the tread dead centre! peed off is not the word, and going by the state of the roads last night I'm 95% sure its either come out the back of a gritter, or fallen off a gritter. Shame I cannae prove it.

But I was wanting to ask, is it ok to use a single 205/55R16 with 3 195/65R15's, or even a pair of each? I don't want to damage the car obviously...

Thanks, JF.