[brucel]

I am looking to replace the space saver with a full sized tyre wheel which will fit in the spare well without using spacers. I have the TDCi with 235/45 R17 tyres. Does anyone know if there is a tyre/wheel combination which will fit (ie is there a narrower width tyre with a similar circumference to the current tyre). The 215/55 R16 for example is narrower and has close enough to the same rolling radius and circumference as the TDCi combo, so does this fit in the spare well without using spacers?
My aim is to have a tyre capable of more than 100km range plus greater safety than the spacesaver.