There are certain, indisputable facts in life. One is that car tyres - and car wheels - are expensive. Consequently, the, er, light-fingered among us have been known to lift our wheels and tyres, by first lifting our cars on to a convenient pile of bricks. In the relatively recent past, car alarms have become smart enough to detect when a car is being jacked up and they can tell everyone in the vicinity all about it. This is 'active security', which is a subject in itself. In this article, we'll look at an example of 'passive security'.
Passive security needs no power source: it is a barrier rather than a whistle-blower. All it need do is be there to be effective. Sometimes, passive security devices are evidently present. However, devices that mechanically prevent car wheels - and car tyres - from being stolen, tend not to shout about it. The thieving fraternity knows what locking wheel nuts or bolts are about and it's rare for a vehicle to lack them nowadays.
How, then, do these devices work? Their operation really couldn't be simpler. If you attach your car wheels to your car's hubs with four or five nuts or bolts apiece, and those nuts or bolts have a hexagon head, the danger is obvious. Replace one fastening per wheel with a fastener that needs a key of some sort to permit it to be removed and the solution is present and evident. Your wheels and your car tyres are as safe as they can be made.
The obvious question that arises is about the key itself. This, rather than being a key as such, is usually an adaptor, which allows a wheel nut/bolt spanner to be used to remove the special fastening it fits. So, what to do with the key, or adaptor? Most people keep it in the boot, or perhaps in the car's glove box. This means your car tyres and wheels are protected by the car's alarm. This could be worse, of course, and what is relevant is that you never know when a car tyre needs to be changed. The only watchword exists when you have to leave your car unattended for a while, say in an airport car park. Having seen a BMW on bricks and wearing no wheels, I can safely suggest that if the wheel key had been in Spain or France with the car's owner, the wheels and tyres would probably have been present when the car's owner returned.
The locking of car wheels and tyres has been refined to the extent that corrosion and wheel balancing problems are a thing of the past. There are some cheap sets of locking wheel nuts/bolts on the market; these can fail even when used properly, so avoid them. Nevertheless, another question arises: what happens if you've lost the key to an unarguably tough locking wheel nut or bolt? One person on the Internet resorted to using a power hacksaw to dismantle the offending wheel and tyre. However, radical resection isn't really necessary. Car tyre fitters have generally encountered this problem before, and keep a range of tools, at least one specifically designed for this task.