Hi, My 2009 Zetec S seems to have the issue of the steering following or tracking to natural curves in the road, bumps and rough road surfaces. When the car passes over rough or angled road surfaces and I am not gripping the wheel tightly the steering wheel will pull to one side or the other. On smooth and flat roads however this is not an issue, the steering wheel is straight and doesn't pull, the same goes for motorway speeds. Is this natural for thicker tyres? I am more used to cars with thinner tyres and lighter steering. The model also has 17 inch alloys. Is this just due to wheel alignment or something else?