Quote Originally Posted by GeoffR View Post
Regular maintenance will NEVER detect the nail you got in your tyre 1/2 an hour ago. Though I did detect it by eye, it looked flatish (15psi). Not that I would willingly buy a car with a Tyre Pressure Monitoring system, especially after having been involved in removing TPIS from a fleet of A320 family aircraft because it was so unreliable.
On my VW Passat I've got Contintental Contact tyres with Conti-Seal and that really works. I saw a nail/screw in a tyre a year or so ago, pulled it out expecting that hissing sound but no, the tyre was still perfect and never lost any air at all.