Big Bertha’s Tyre Pressure Management

Big Bertha’s Tyre Pressure Management

Big Bertha’s tyre’s cost Big Bucks! And failure is either due to punctures or blowouts, which are normally caused by running an under inflated tyre at high speed.  The set tyre pressures are governed by the axle weight, speed and surface types – all taken from the Michelin tyre data sheet.

Dave fitted a tyre pressure monitoring system (TPMS), with alarms, a couple of years ago.  The sensors attach to the end of the valve stem and transmit wirelessly to a monitoring unit on the dashboard.

The dashboard monitoring unit. You can set alarms for over and under pressure and over temperature.

Each wheel has a sensor mounted on the tyre valve stem that transmits pressure and temperature to the monitoring unit. Great, but a real pain to remove and re-install, for each tyre, when inflating or deflating.

Unfortunately, the TPMS did not warn us of the blowout we suffered in September 2022 and the system seemed to be faulty as it continued to report normal pressure / temperature even after the blowout had occurred.  This has been taken up with the manufacturer, Tyrepal, and David has returned the system for investigation. Tyrepal in turn provided us with a new system with a new type of ‘always on’ sensor and we will try these out. In the meantime, we bought a new set of tyres for BB.

After our very dramatic and frightening blowout on our rear right tyre, our TPMS continued to show normal pressure and temperature for that tyre.

A new set of tyres for BB and a big hole in our bank account.

We normally deflate our tyres when running on tracks and even more so if we are on sand; but to deflate and re-inflate afterwards can be a palava: remove sensor from valve stem, inflate the tire (or deflate), measure pressure, repeat as necessary and then reattach the sensor. Times four.

A South African company, Ti Systems SA, has a patented system, tyFlate, to make this task easier; comprising:

1/ a T piece that attaches to the valve stem allowing the TPMS sensor to be permanently fitted, along with a quick fit high flow valve (the Schrader valve in the valve stem having been removed).

2/ a coiled air hose, quick fit connector and housing, installed close to each tyre.

3/ an air regulator on which one can set the desired pressure, supplied from one of the truck’s air tanks which is filled by the engine mounted air compressor.

This T piece allows the sensor (new type, on the left) to be left in place whilst inflating the tyre via the big bore quick fit valve (on the right).

A coiled hose is used to connect the tyre to the control system. All tyres can be connected at the same time.

The inflation/deflation controller.

Airing up is now a matter of connecting all four wheels to the coiled hoses, setting the desired pressure on the controller and waiting. Because the front tyre pressures are lower than the back, first the front tyre pressure is set and once achieved, the front air coils are disconnected and the higher rear pressure is then set.  Deflation should be equally easy – adjust the air regulator to below the actual tyre pressures.

Dave will report back on how well this new setup works in future posts.

Update October 2024

We have been using the system for more than one year now and here is our feed back.

The new TPMS from TyrePal is working much better. However, there sometimes is still a lag between actual tyre pressure and reported tyre pressure.

The tyFlate system is working well. It is essential to Loctite the brass T piece to the valve stem and to Loctite the threaded hollow barrels into the T piece. The quick fit valve and TPMS come with ‘o’ rings, so they don’t need loctite. We don’t use the tyFlate regulator to set tyre pressures, instead we monitor the in-cab TPMS display and turn the feed to the tyFlate regulator on/off. The above has made our deflation and inflation tasks a breeze.