TPMS

Hi Bruce. I have a SensaTyre internal system installed on the 200 Series and the Tvan. The sensors are located within the tyre itself actually attached to the rim by a steel band. The instructions that came with the system indicated that I should install the receiver under the vehicle, however I installed it on the cargo barrier to avoid damage from stones and dust. It does work well, however it can be a little slow in picking up the Tvan sensors.
Fortunately it has only had to demonstrate its worth once. At that time whilst travelling east of Alice Springs the alarm sounded. I stopped and the tyre was less than half deflated. As the damage was in the sidewall I did have to replace the tyre but if it had been damage which could have been repaired then the tyre would have suffered no damage from the deflation process.
Interestingly of greater value than the pressure readings are the temperature readings. You certainly get an indication of inadequate or adequate inflation by monitoring this aspect.
Overall I have been pleased with the system and of course having internal sensors means that tyre inflation and deflation is as normal and sensor loss is not an issue. Supposedly the sensor batteies have a seven year life span. Time will tell.

Take a Iook at Masten tpms options.
Masten at Digoptions

Quite a lot of options for internal and external sensor units.

I have had the HD truck 8 sensor model for about 3 years.
Masten 8 sensor external

I have the obvious 4 on the vehicle wheels, 2 for the main spares, and 2 for the inevitable camper trailer down the track (no pun intended).

It’s saved me both tyres and inconvenience on a few trips.
Catching a pressure problem early is both and economic and safety factor.

As far as reduced inconvenience, I had a slow leak in front tyre on a Simpson Geos trip, without removing wheel and bathing to find the pinhole, I was able to monitor the pressure and when it got to say 8psi, I could pull over, inflate to ~ 20, and I’d be good for a few hours again.
Rather than pull up more regularly and check with an air gauge.

A mate has the solar 4 main wheel sensors (smaller sensor) and is very happy with it.
Masten solar

A couple of points.

I find the temp part of the readings next to useless with external sensors, they are good for telling you the air temp outside though :)
They will rise from ambient temp to about 24c usually, and only change with external influences.
The spare under the back (protected under tray) will read higher temp then road tyres, the one on the roof rack (in cold rushing air) less both in temp and pressure reading.
Internal ones may be more accurate / valuable if you are worried about this, but I find just watching the pressure movements is plenty to tell me if something isn’t right.

I have 2 valves per wheel, as airing up / down would be a pain with the security spammer on the sensors all the time.
Sensors are left on permanently and the 2nd valve used for pressure adjustments.
You won’t need this if choosing internal sensors, but I just felt external was the preferred way for me . . . in fact I had one fail at the start of a recent big drive, and was able to swap one from one of my spares to get me through.
Turns out it was just the battery as suspected, that seemed to have failed prematurely as the others were no issue over 13700km.l and since then (June / July).

It’s nice to know they work when doing various things, like getting fast deflate alarm when airing down with the ezy deflator.

Once you have any sort of tpms and start getting feedback from your tyres and how they change with air, tracks work, gravel / bitumen roads at varying speed, and even sun on one side of your vehicle, you will wonder how you ever did without the peace of mind.

I have the INNOTECHRV 10 SENSOR TIRE PRESSURE MONITORING SYSTEM fitted to my D-Max and Caravan.

Having 10 sensors means I can monitor all road wheels plus the car and van spares.

This units does not need a repeater for the van tyres.

I went for the external sensors as it is much easier to replace batteries and also rotating the tyres, I can leave the sensors in the same location and do not need to re-program the receiver.

I currently have a Davies Craig set and find it works well and easy to change set pressures etc, good unit. Had a tyredog set previously worked well but less easy to program and then it died, but did maybe 5 years.
My vote is for the Davies Craig.
Cheers

Thanks to everybody for their input. I wanted an external monitoring system so that I can easily swap from my ute to the warden's car in the hope that if she gets a puncture, she may pull over and get the RAA to help out rather than ruin a rim and tyre. The Masten was another that I had on my list but have probably decided to go with the Davies Craig as previous experience with some of their products has always been good.
Thanks again - bruce

Im on my 3rd brand after 10 years. There are 4 features I like about the masten. Also sold as sidewinder and Safety Dave.
-If you tow, you can easily add or delete the trailer wheels on the alarm and display.
-You can change per axle alarm pressures fairly easily for on road , off road use.
-you can set the alarm down to 6 psi for sand etc.
-it has good range and automatically turns on and off with movement / vibration.