Tyre Pressure Monitoring System
by Laurie Kibblewhite - 4WD Oz DVD
have had numerous incidents with my caravan over the past few
years, where I have lost a wheel, destroyed a rim, and managed
to save one by pulling into a rest bay by sheer chance just after
one of my caravan tyres shredded itself. I have also had a couple
of punctures that we discovered because of a device I was using
at the time. It was always a back wheel that was the culprit (I
have a tandem axle van).
the wheel loss was my fault entirely - didnít check the wheel
nuts after a service ..... but the rest .....
I use a Weight Distribution System, which keeps my caravan incredibly
stable - even on three wheels - we followed the drag marks 40
kms back along a dirt road trying to locate my lost wheel - never
did find it ...... and it was noise that alerted me to the wheel
that got destroyed. A twitch going down a hill was also an indication,
but all caravans twitch at some stage .......
I installed a Tyre Pressure Management System (TPMS) on my caravan.
(basically a car system, but fitted to my van - I figured I would
know when my car tyres were going down). It worked with the transmitters
fitted inside Dust Caps, and sent tyre pressure and tyre temperature
information to a display affixed to the windscreen. It alerted
me to two punctures that we got - one in a rest area, and one
in a service station, and those two alerts basically paid for
the TPMS. However, two caps were destroyed when tyres disintegrated,
and the replacement caps were $100 each.
And so for a while (I was also off the road with illness for 18
months) I basically had no warning system on the van. When planning
for my current trip, I recalled that I had a tyre go flat on the
Kalumburu Road and it was another traveller who brought my attention
to it - we were travelling with reduced tyre pressures, and the
road being rough, were sliding around a bit anyway. And so I decided
to look at what was available, and it was a post on Facebook by
another traveller, (I canít remember who it was and canít find
the review) that led me to investigate the TPMS manufactured by
decided that I needed an 8 wheel system, one that covered my car
AND my caravan. I found their website (www.inawise.com), found
my local distributor (Albany Bridgestone Tyre Service - ABTS),
and made my enquiries. ABTS had been a distributor for two years
and had never had an enquiry, and so handed me the brochure I
required, and I headed off to do my homework. I worked out from
my experience with my previous system what I needed to know about
this unit, and went back to ABTS, who contacted INAWISE and passed
on my queries. Eventually, I needed to know a few more technical
details, and so ABTS gave me the number of the company, and I
spoke to Eddy from INAWISE about my concerns.
The main points were
Does the unit register when you lose a wheel?
How are the transmitters fitted to the wheel?
How much does it cost to replace transmitters?
How long do the batteries last?
was not a convincing yes to losing a wheel. The company is working
on that scenario, but it wasnít perfected at that time.
The transmitters replace your valve stem - they are fitted inside
the wheel, and so loss of battery and/or dust cap is not a problem
The figure was quite low - much less than the $100 for my old
The battery life should be the life of the tyres at least ( and
most tyre sets last several years - in my case more often - every
couple of years) and so time will tell.
decided to go ahead with the system, and ABTS were excited when
it turned up, to be involved in installing this high tech gear
into my wheels. The instruction book came out, and we decided
to wire the unit through the cigarette lighter - it can be hard
wired. The antenna has a really strong magnet and hangs underneath
Ironically, the day of the fitting coincided with their second
enquiry about the system, and the so the enquirer was able to
see the system and watch it being fitted.
so how well does it work?
towed my van home, and next morning came out to my car, and the
unit started beeping, and one of the numbers on the display unit
was flashing, and the tyre pressure was indicating low...........
and so, I checked the tyre, pumped it up, and towed the van back
to ABTS, who found the valve stem was loose. They pulled the tyre
off and checked the alignment of the sender as they tightened
up the stem. All fixed, and no more problems.
were travelling north, when the beeper took off and I took a few
seconds to realise that the TPMS was talking to me, and one of
the numbers was flashing. The tyre pressure on one of the tyres
was reading high. WHY?
then I remembered. The unit is factory set at 50 psi, and will
tell you if you are 30% over or 20% under that figure. Well, on
the van, that was fine, but I had been running my car at 40 psi.
And so we had to tell the unit that that was our cold tyre pressure
number. This is done by pressing a button at the back of the unit
for 5-6 secs, and this resets and overides the factory setting.
Fine, except I later set my rear tyres on the car to 44 psi, and
when they got hot and increased the tyre pressure to 52psi, the
unit told me so. ( 30% of 40 psi is 12 psi, and 52 psi had been
exceeded.) And so it meant that I needed to reset the cold tyre
We were doing a run on dirt roads out of Halls Creek, and so I
reduced the tyre pressures to 30 psi, and was again warned by
the TPMS that my tyre pressures were below the 20% threshold,
and a display reset was required to fix that.
The unit works, and works well.
My only gripe was the display unit itself. It is Green LED lighting
behind a dark, glossy convex screen. The book tells you for best
results to mount it away from the sun. Being a windscreen mounted
unit, that isnít easy to do, and so, during a bright sunny day
it is difficult to monitor (even more so when wearing sunglasses,)
I phoned Eddy at INAWISE, and we discussed this. Surprisingly
(or maybe not), they have had requests from owner to install a
switch to turn the display OFF, and just have the audio working.
They found the unit a distraction. Me, I like to see what is happening,
and when the warning signal is transmitted, I can see instantly
which wheel is having the problem (flashes).
INAWISE are addressing these concerns.
unit works, it covers ALL of my wheels (and will do up to twelve
wheels - it was developed for trucks), and is in my opinion well
priced. You only have to save a couple of tyres at $300 each to
have the unit pay for itself.
I paid for this unit, and have written the review to alert caravanners
that such a system does exist, and works, and in my opinion, is
If you are reading my trip blogs on the Savannah Way,
you will have noticed that I had a slow leak that wasn't immediately
obvious from looking at the tyre. The pressure was set at 40 psi,
and once the leak got below that, the TPMS did it's job when I
fired up, and let me know that I had a problem, which wheel, and
the current pressure. This review was written a number of weeks
before that incident.
We had a couple more tyre problems that this
unit alerted me to. One was near Winton in Qld, when I obviously
ran over something that really whacked the underside of the vehicle.
A second or two later, the TPMS started beeping, and inspection
revealed that the rear tyre (same one as before as it turned out)
was flat. It turned out to be a different problem, a wide cut
in the tread of the tyre - possibly a piece of metal, and the
tyre was dead.
On my way back to WA, the TPMS watned me again
that I had a leaking tyre. I chose to pump the tyre and keep going.
It alerted me again next morning. It was certainly doing its job.
Turns out that on my diversion to have a look at Ivy Tank (video
on YouTube), I managed to stake a tyre, and the twig was still
embedded in the wall of the tyre.
Surprisingly, ALL of these tyres were on the
car, and the caravan tyres gave me no problems at all.
you would like to contact me or email
your thoughts or comments, please feel free to do so. I would
love to hear from you
more photos, visit Lesley's site. Queensland,