You have got the same logic as me in keeping the tyre size as original fit. A tyre compound that doesn't harden when temperatures fall below -7c will offer the grip advantage needed over the winter months. It would be interesting to see a test of 225's vs 205's both in winter compounds to really see if a difference exists, probably minimal. It grates on me to put narrower tyres/steel wheels on as the bulk of the time I will be driving on mainly cold/wet tarmac during the winter months. I expect the reason that narrower tyres are recommended is to allow for fitment of snow chains, my Octavia Scout appears to have plenty of clearance as does the Yeti and there is always the option of SnowSocks or the Michelin Easy Grip Composite Snow Chains (low in profile) as a back up. My other concern and why I want to stick with original tyre size is with the insurance companies varied response to changing your wheels/tyres/speed index from factory fitted tyres, some see it as a good excuse to load your premium.
