I have been running the Smartire system(
www.smartire.com) in my Gen 3 for the last 5 years. Unfortunately this system is not at all well supported in SA and getting any spares is a mission. The system has paid for itself twice already with early warnings on tyres getting hot when running low pressures and also twice on punctures where I could stop and replace, to have puncture fixed later. Had I not had the system my tyres would have looked like yours Simon.
What I like about the system:
1.Mounted inside tyre with no caps etc on outside that could be damaged or stolen
2.Neat cabin display which is reasonably user friendly
3.Intelligent computer adjusting required pressures to temperature experienced. This is confusing at first but works well once you understand the principal.
4. Works with up to 20 tyres if I recall correctly so worked great to monitor my Xplorer caravan tyres as well.
What I don't like:
1. No support through the local agent who actually use it to manage fleets of truck tyres.
2. The sensors inside tyres needs to be properly installed otherwise they self destruct on heavy corrugations.
3. The sensors is sealed and the result is that you need to replace the whole thing when the battery goes flat, about 5-7 years, which is a pain if you don't have local support.
4. The sensors are easily damaged by a tyre repair shop if they refit tyres and are not made properly aware of the fact that the rim is fitted with a sensor inside.
5. if rotating tyres you need to remember to tell the system where the new tyre is located otherwise it might indicate a flat front left where it might be right rear. With an outside cap system this is more easily managed manually.
I would say that this is probably one of my first items on a list of must haves in a 4x4 vehicle where the tyres are often pushed to the extreme and tackling rough terrain. At avg R2500 per tyre the system cost pales in comparison. Do however make sure you buy something that will be supported in a few years time.
I would buy the Tyredog system if I need to replace currently in South Africa.
CATS