My 2011 CR140 TDi SE is fitted with the standard 17" Triffid alloy wheels shod with the recommended 225/45 R17 94W tyres (Goodyear Efficient Grip).   Whilst at work yesterday I was parked next to a colleague in his 2012 diesel Audi A4 Avant, I noticed that it too has 17" alloys but was instead fitted with slightly higher profile tyres: 225/50 R17 94W (Michelin Primacy 3 on the front and brand new Dunlop SP Sports on the back).   I was surprised at how much of a difference the extra profile t