Munich - Tyre blowouts have become extremely rare occurrences. However, despite technological progress lack of care, insufficient pressure and damage from incidents like kerb collisions may still cause a blowout. When this happens, the main priority is to keep calm and bring the vehicle to a controlled standstill. TÜV SÜD's experts have tips on how to avoid the situation from the outset.
"Anyone that takes care of their tyres, avoids mounting kerbs and other potentially damaging actions, and ensures tyres are always at the correct pressure can usually continue using their tyres for around six years, or until they reach the legal minimum tread depth of 1.6 millimetres", advises Michael Staude, TÜV SÜD’s tyre expert.
Finding out: The manufacturer's tyre pressure specifications are given in the car manual and the sticker inside the fuel tank flap or door. As almost all cars can be driven with a range of tyre dimensions, different pressures are often given for the various tyre sizes, which drivers must be sure to observe. A few car manufacturers provide tyre pressure information in kilopascal (kPa), an uncommon unit albeit correct in terms of physics. Conversion into the far more commonly used bar is simple: 100 kPa equal one bar.
Moving up: Do not undercut the vehicle manufacturer's specifications. Even a shortfall of 0.2 bar will account for up to five per cent higher fuel consumption in city traffic, while 0.5 bar can cost an extra litre per 100 kilometres and may also be a safety hazard at higher speeds. But manufacturers' figures are generally a “comfortable” value and 0.2 or 0.3 bar more will definitely do no harm. Pressure which is much higher than the specifications, however, will impact negatively on driving characteristics and cause uneven wear on the tyres.
Be cool when you check: All tyre pressure figures are given for cold tyres. Even trips of less than ten kilometres will cause tyres to heat up. Because of this, do not let air out of the tyres, but instead fill tyres to slightly higher than recommended in the manufacturer's instructions (0.1 – 0.3 bar).
More speed, more pressure: For longer motorway trips, TÜV SÜD recommends tyre pressure that is 0.3 bar above the general specification. However, full load pressure is not generally recommended for driving at high speeds. Full load pressure is calculated on the basis of the vehicle load; while tyre pressure of almost three bar is recommended for larger estate cars, it would be unsuitable for unloaded vehicles even for motorway driving.
Load up, then top up: Drivers planning to pack their car to the roof or use all available seat space for a longer journey must increase their tyre pressure. Return the pressure to normal after the trip! Tighten those screws: Valve caps are not there for decoration, but act as covers and protect valves from dirt that might otherwise interfere with the functioning of the valve by causing loss of air.