SAB UCHEAGWU is a friend, a brother and a colleague whose contributions have richly improved my knowledge on tyre care and the challenges it poses to road safety management in our country. Since our paths crossed some years back, he has been a mentor I will never forget in a hurry. A good number of the materials I share with you are courtesy of SAB. Today, as I look on driving risk behavior, I wish to share this rich material from him on tyre blowout hoping that travelers will get needed safety information preparatory to the December rush.
Tyre blowouts are among the major causes of fatal accidents that has claimed the lives of different categories of motorists and as we gradually await this year’s Christmas celebrations usually characterized by increased irresponsible driving, many more may still die due to tyre blowout. That is why this focus should be of serious concern for motorists planning to travel this season and even beyond this coming festive season. This piece will raise awareness on the major but preventable causes of tyre blowouts and how they can be prevented.
Incorrect tyre inflation could also cause accidents in other ways. When a tyre is incorrectly inflated (over inflation or under-inflation), it makes a partial contact with the road surface and so does not have a firm grip on the surface. With overinflation, the edges of the contact patch (the part of the tyre that should be in contact with the road surface) do not touch the ground. While with under-inflation, the crown (the middle portion of the tyre) of the contact patch does not touch the ground. So either way, you have an impartial contact of the tyre on the road surface and so less grip.
The extent to which the piston is pushed depends on the pressure in the tyre. The higher the pressure, the farther the piston will be pushed and the higher the reading. On fortunately, with heavy usage (as in everyday application by the vulcanizers), the hole through which air passes to activate the piston can be constricted by dust coming out from unprotected valve stem of the tyre and also by the rust due to moisture from the damp air coming out from the tyre.
With the air passage so narrowed, the amount of air passing through it no more corresponds to the air pressure in the tyre and so a faulty reading results. Worse still, when this happens, there is no way the user will know. It will still be giving reading but highly incorrect readings. That was the case with vulcanizer I had the encounter with. After I explained to him why his gauge was the one at fault, he did not agree saying he had been using the gauge for long and never had any problems with it. Because of the seriousness of the issue, I had to prove to him conclusively that he was wrong and endangering the lives of innocent road users. We had to get a brand new pencil gauge that has not been compromised by dust and rust. When it was used to gauge my tyre, the reading corresponded exactly to what I got with my gauge. He had no more argument and willingly complied with my demand to submit the dangerous gauge to me because I insisted that he must not use it again. This type of gauge is also affected by temperature, humidity and altitude. So the readings got at different locations and weather conditions could differ substantially. Not only that, most vulcanizers use this type of gauge, they use it on daily basis and for years. The one used by the vulcanizer mentioned above had signs of abuse and over use all over it. It is the same story North, East, West, and South.
But why do the vulcanizers use this type of gauge? Essentially because it is the cheapest gauge in the market. Not only that the vulcanizers use the pencil type of gauge, the use one gauge for all tyre pressure. Using one gauge for all pressure measurements is a blunder. Why? Every gauge has a calibration range designed for a certain pressure group and will only be accurate when used for such pressure group. Gauges are accurate when used to measure pressures whose values fall within the middle range of the gauge. For instance, if you have a gauge with range 0-60psi, the middle range is 30psi. this gauge will accurate for pressures whose values fall around 30psi. so pressures that should be measured with this gauge should be about 25-35psi. Gauge of range 0-100psi should be used for pressures of 45-60psi or close. Gauge of range 0-160 should be used for pressures of 75-120psi. So if one uses a gauge not designed for a particular pressure group, one will get incorrect and misleading reading.
Unfortunately, the vulcanizers are innocently ignorant of this. Most of them use 0-160psi or 0-120psi gauges for all their tyre pressures, thinking that a wide ranged gauge should accommodate all the tyre pressures they measure. This sounds logical but grossly wrong and very dangerous.
You can imagine the combine effects of Blunders 1 and 2 discussed above. So, while you drive into the vulcanizers shop to fix ones tyre pressure problem, the vulcanizer inadvertently sets one up for the very problem one has gone to fix. The result is that almost all the vehicles that ply our roads have their tyres incorrectly inflated. Just run a random check and you will confirm this. What a time bomb these vehicles could be. You can imagine what could have happened if had driven away with 60psi pressure in a tyre designed for 35psi. Yet this is the fate that all motorists face every day. How many people have a personal gauge confirm what the vulcanizer pumps into their tyres?
Since lives are involved, reliable tyre gauge cannot be compromised. The correctness of the tyre pressure is as good as the gauge used to measure it. So it is of vital importance that tyres are accurately gauged and pumped. This therefore emphasizes the urgent need for the vulcanizers to use accurate and reliable tyre gauges that should also have a way of telling when they malfunction otherwise one will be getting readings without being aware of it and that could mean disaster.
A reliable gauge is one that has a fully geared precision movement parts and with bourdon tube. Unlike the piston-plunger-type gauges (the pencil type), the bourdon tube movement is not affected by changes in temperature, humidity or altitude and so will give correct reading anywhere and anytime. When it malfunctions, the needle on the dial will indicate by erratic movement when engaged to gauge tyre pressure. A sample of this gauge has been presented to the vulcanizers and fortunately, they are willing to use it. A vulcanizer should also have at least two gauges of different ranges (0-60psi and 0-100psi) as explained above.