We probably take for granted the majority of tyres that we see every day – on cars, motorbikes, buses and lorries, for example, – as they are fairly standard in size and appearance for each of the different vehicles. There are variations in quality, road holding, noise reduction and fuel consumption, which a reputable site such as Avatyre will explain when you are searching for tyres online, and ordering tyres for most vehicles is fairly straightforward.
Some special tyre requirements
Ordering tyres is not quite so simple for other vehicles which may have particular requirements however. Some examples are listed below.
Aircraft tyres have to withstand landing speeds of up to 250 miles per hour and can wear out as quickly as after just 10 take-offs and landings, though a far higher number (around 200) is more usual, so the construction has to be extremely tough compared with car or even lorry tyres. We’ve all probably experienced aircraft landings when the plane “bounces”, which will obviously increase the wear on the tyres. There is some debate amongst airlines as to whether tyres last longer with “hard” landings, when the tyre will stop spinning more quickly, or with smooth landings, which are more comfortable for the passengers.
Another difference with aircraft tyres are that they are usually used at up to 200 pounds per square inch pressure (psi), whereas cars are generally set at around 30 psi. They are also filled with nitrogen (as are motor racing tyres), because it is more stable and doesn’t affect the tyre pressure when the tyre heats up.
Most aircraft land on the main gear – the two sets of wheels at the back of the plane (the big jumbo jets have up to eight wheels in each set), then lower onto the front set of wheels and it is actually the front tyres that usually wear out the quickest. As each tyre for a jumbo costs several thousand pounds new, replacement tyres is an expensive business, though they can be re-treaded at least once.
Flotation tyres are recognised as the best way for vehicles to cope with off-road conditions, such as soft sand, snow, swamp or mud. The idea is that they will keep moving as long as they stay on top of the surface. The only problem can be when you have to stop, as they may then sink into the sand or mud, so it is best to select the place to stop very carefully! Some traction is also necessary for the forward movement and many farmers have found flotation tyres invaluable as they compact the ground far less than conventional tyres.
On a recent holiday of a lifetime in Australia, I went on a trip that included a trip along a beach on Fraser Island to visit a wreck. The vehicle used to cope with this terrain had four enormous flotation tyres, which gave it the slightly odd appearance of a minibus set up really high, but it did the job admirably.
The Lunar Rover is an example of a vehicle which few of us are likely to see, let alone drive, but once again there were very specific requirements for its tyres, including being able to cope with extreme temperatures of 150 degrees below freezing at night. As it would have to traverse a variety of surfaces, the specification was for it to be as light in weight as possible, with a maximum below 659kg and four-wheeled driving.
Moving house is something that most of us do at least once and we are all familiar with the typical removal lorry, with standard lorry tyres. In a recent TV programme, the term “moving house” took on a whole new meaning, when specialist contractors were called in to move a whole house to a different location. The steps involved included removing the roof in one piece, then cutting through sections of the house so that they would fit on board a gigantic lorry, to be transported to the new location and re-assembled.
As you can imagine, the vehicle involved was something of a leviathan, with tyres to match. The operation also took place in the United States, where the roads were straighter and wider. Perhaps the majority of roads in the UK towns and villages would need to be increased in size before this kind of house move could become practicable!