Inflation stops irritation

Press, 5 December 1985, Page 66

Inflation stops irritation

Most people know that their car’s ability to accelerate and brake efficiently, to hold the road and steer, depends on the tyres, but many fail to realise that a car will not perform any of those functions safely if the tyres are not inflated to the correct pressure. While appropriate tyre pressures are important at any time of the year, they assume special significance during the summer months when car owners, taking annual holidays, often drive greater distances in heavily laden cars and in wanner temperatures.

Radial tyre pressures should be increased by 15 to 30 kPa (2 to 4psi) if the vehicle is going to be operated fully laden or driven long distances on the open road, because this increased pressure will provide better control of the vehicle and reduce tyre operating temperatures. If it is proposed to use the car for towing, the pressure of the rear tyres only should be increased by a further 15 to 30 kPa up to a maximum of 230 kPa (34psi). Those guidelines are rule

of thumb and it would be sensible to seek expert advice about pressure from an M.T.A. tyre retailer or tyre fitter before starting off on a summer holiday.

Tyre pressure increases in the first few kilometres of driving because air in the tyres heats and expands. In cross-ply tyres, the rise can be as much as 15 to 30kPa after three kilometres and, in fact, the rise in pressure could be as much as 96 to HOkPa (14 to 16psi), on motorways in the height of summer. With radial ply tyres, the pressure build-up will be less, but still quite significant. Of course, pressure buildup can create serious trouble. It could lead to a blow-out, particularly if the tyre casing has suffered minor damage at any earlier stage in its life. That is but one good reason why anyone contemplating a summer motoring holiday is always well advised to visit an M.T.A. tyre specialist and have the car’s tyres, including the spare, inspected and thoroughly checked before starting off.

It is simply not good enough to conclude that tyres are in tip-top condition if they are of more than the regulation tread depth, although that is always a plus factor and particularly in summer.

The point is that the occasional summer shower can be much more lethal than winter’s rain-slicked roads. Consistent rain in wintet tends to wash roads clean of oil and rubber. A summer shower on a road well coated with the oil and rubber of summer traffic almost instantaneously transforms it into a skating rink, and it is then that a tyre with plenty of tread will not only disperse the surface water but will also afford all the available grip on the road surface. Be that as it may, most of the summertime and holiday troubles motorists encounter have their origins in overloading. Not counting fan-belt failures, a common cause of holiday trouble, you find that most other troubles are confined to engine overheating, transmission problems and tyre failure. While the majority of motorists try to ensure that the weights they carry in their cars, or tow behind them, are within the limits specified in owners’ handbooks, many of them fail to realise that the total weights are actually much greater. For example, a caravan can be loaded to the extent where it is carrying almost half its own weight, while the weight of a trailer and powerboat is very consider-

ably increased if the powerboat’s fuel tanks happen to be full.

People can help them-, selves towards enjoying a trouble-free holiday by consulting their M.T.A. garagemen and specialist tyre dealers, particularly if they are contemplating carrying or towing heavy loads.