Jim Blackstock shows how to fit an aftermarket caravan
tyre pressure monitoring system
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Photos: Noah Samuel-Blackstock
Several months ago, when we looked at wheels and tyres, we mentioned how many manufacturers of cars – and of modern caravans – fit tyre pressure monitoring systems (TPMS) to their vehicles. The idea is not to eliminate the need to regularly check your tyres but to give you an early warning of a loss of tyre pressure and hence, enough time to bring the outfit to a halt safely rather than suffer a sudden loss of pressure and, with it, control.
But what about older caravans that were built before the technology became widespread? Well, the answer to that question is simple; fit an aftermarket system such as the one I’ve got from TyrePal.
This does effectively exactly what the manufacturers’ systems do and provides you with a realtime indication of your tyre’s pressures and, more importantly, warns of a drop in pressure that could lead to a loss of control. And if you’ve ever been unlucky enough to have a tyre go flat suddenly on a car, let alone a caravan, you know that having advance warning can be a potential life-saver.
The TyrePal system can be added to single or twin-axle caravans, as well as horse trailers and even up to large lorries – the sensors can read up to 99psi and to speeds of 120mph and the monitor can register up to 22 individual sensors; you buy the kit you need but, can easily add more sensors if you need to. So, for example, though we have just added two for the caravan here, we could add four more for the car (it doesn’t have TPMS) for just the cost of four sensors (£25 each) or add another two if we upgrade to a twin-axle caravan.
So how easy is it to fit peace of mind? Let’s see…
Once the two halves were separated, we inserted one of the included batteries into each of the sensors and screwed them back together
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As the sensors sit directly on the end of each tyre valve, the original cap needs to be removed but we kept it safe just in case
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The first thing to do was power up the tyre pressure sensors themselves. One sensor fits to each of the tyre valves
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The included tool splits in half to locate and unscrew the two parts of each of the pressure sensors
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The display unit sits unobtrusively on a suction mount to show your pressures at a glance and highlight any problems
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We tucked the repeater behind a trim panel in the boot, where it could receive the signal from the tyre sensors and relay it to the monitor
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When the red light is lit, it is powered up and when repeating a signal, the light flashes to indicate data transfer
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Before continuing, we checked the system was working, by removing each sensor. The monitor showed 0 psi and an audible alarm sounded
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With each sensor now working correctly, we tightened the locknut with the supplied cranked spanner and check for leaks with soapy water
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We then unfurled the dust cover that we had rolled on to the valve stem. Note this covers the sensor completely when fully unrolled
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We pressed the ‘Code’ button again and that sensor position was stored. We repeated the process for the other tyre as well
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The system has a range of 7m but for longer outfits, a repeater extends the range. We wired ours to an ignition-switched live in the boot
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Once both sensors were installed, we made sure they read correctly. We needed to add a little more air as we lost some fitting the sensors
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We then held the ‘Set’ button down to determine the low pressure alarm setting. By default, this is set at 30 psi from the factory
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To give room to work, we rolled the dust cover back onto the body of the valve stem, out of the way of the threaded portion
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The instructions suggest 15% below the recommended pressure; we set ours to 47 psi. The maximum temperature alarm was left at 70°celsius
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Now we needed to get the monitor unit close to the sensors to connect them all up, wirelessly
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At this stage, we set the tyre pressures to the right level, as if we were heading off with the caravan
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We held the ‘Code’ button for five seconds and used the ‘-’ button to select the tyre that we were programming
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Next, the sensor locknut was fitted to the threaded part and wound on as far as it would go, to the bottom of the thread
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The monitor registers the signal for that sensor and stores it against the selected wheel/tyre position in the display
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Included in the kit is a dust cover for each of the pressure sensors. We fitted this to the valve stem first
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It was then time to fit the sensor to the tyre. We applied it and allowed some air to escape, as per the instructions, then tightened