I have a 2005 Mondeo Titanium X 2.2 TDCi, bought two years ago to tow a caravan. This has four 255/40ZR18 low profile tyres on alloy wheels. These tyres hammer noisily over rough surfaces, tramp sideways on rough corners, are easy to pinch against even low curbs and are very expensive. The fifth is a ‘space saver’, although the well in the boot, while wide enough for the full-size tyres is too shallow for them. I have seen advertised basic pressed steel Mondeo wheels with narrower, deeper and cheaper tyres - would there be a downside if I fitted five of these and sold the alloys on?