Car Safety information: Tire Pressure and Worn Tire

One in three cars driving on any roads has insufficient pressure in its tires. According to research carried out by one of the biggest tire manufacturer in Europe, constant driving when the car pressure is just 0.3 bar too low can reduce the service life of the tire by 30%. And the consequences may well be dangerous, because insufficient tire pressure makes braking distances longer, vehicle handling becomes 'spongy' and, particularly when driving at high speed, there is an increased likelihood of a tire bursting. At the same time, cars with insufficient pressure in their tires use more fuel than necessary; consumption goes up by around one and a half per cent when the car's tire pressure is just 0.3 bar (i.e. around an eighth) below the manufacturer's recommendation. With a medium range car, that makes an average difference of 16 liters per year. In addition, the higher fuel consumption means 38kg more CO2 emissions per car per year, something that could be avoided. If one calculates these increased CO2 emissions for the 33% or so of cars driving in any road with the wrong tire pressure, this adds up to an annual total of over 608,000 tons of CO2 - all of which could easily be avoided. These calculations were based on a car using 7.5 liters of fuel per 100 kms (38 mpg) and doing 15,000 kilometers (approx. 10,000 miles) per year. With around 46 million cars currently registered in one European country alone, that means that some 15.2 million of these are driving with insufficient tire pressure.

By checking your tire pressure regularly, you do yourself and the environment a favor. At the same time, it helps you to identify creeping pressure loss caused, for example, by having a nail puncture or a faulty valve. Therefore, expert’s recommends that motorists check their tire pressure every two weeks or each time the car has been refueled - for the sake of their own safety, for the environment and for their wallet. Where possible, tire pressure should be checked whilst the tires are still cold.

Worn Tires Can Send You Flying, Especially of Wet Roads

It's that time of year when autumn has set in, confronting us constantly with wet roads. That not only dulls moods but also reduces the joys of driving. The problem is not only the amount of rain, which might even be exceeded in summer, but the fact that high air humidity and a lack of sunshine don't give the roads much of a chance to dry off. Driving in the rain on wet roads is, however, not much of a problem if one adheres to a few rules: Slow down and keep your distance. And above all, make sure your tires have sufficient tread depth. Otherwise, you may unwilling end up "water skiing".

Aquaplaning is when the tires start to glide across the roadway on a film of water, destroying the contact between the tire and the road. The driver has trouble steering, braking or accelerating the vehicle. Aquaplaning usually occurs on the motorway. And according to experts, it is aggravated by truck track grooves, high speed and lack of tread depth. As a study conducted by a reputable car magazine Auto, Motor and Sport (volume 17/2006) shows, a worn tire is much more prone to aquaplaning than a new one with sufficient tread depth. A longer braking distance on wet roads is even more dangerous. The test cited demonstrates that on wet roads at a speed of 150 km/h, the braking distance with a worn tire (tread depth of 2.5 millimeters) is 50% longer than with a new tire (tread depth of eight millimeters). Where a car with new tires has already come to a full stop, the other vehicle roars past at 72 km/h. Experts also have found out that on a wet road, a vehicle with tires worn down to a tread depth of 1.6-millimeter needs almost twice as long to come to a full stop with locked brakes as does a vehicle fitted with new tires.

New tires are supplied with a tread depth of around eight millimeters and it is recommended that that tires be replaced when they have worn down to about four millimeters. This applies conditionally for summer tires and in all cases for winter tires. The tire's performance is affected already at a tread depth of less than four millimeters.

The tread depth is measured in the main grooves. On modern tires, a tire wear indicator (TWI for short) is very useful in this regard. The statutory minimum tread depth of 1.6 mm has been attained when these supplementary crossbars are flush with the surrounding tread. Tread depth can also be checked with a coin. The coin is inserted into the tread depth. If the coin depth reaches to only about 3 millimeter, the tire has insufficient tread depth and is therefore needed to be replaced.