Instead of a spare tyre, I see many cars today are equipped with tyre repair kits. And some cars have what they call run-flat tyres. Are these superior to the old-fashioned spare tyre?
Run-flat tyres allow you to get to the nearest service station or tyre shop with zero effort.
Their reinforced tyre walls prevent a deflated tyre from collapsing. Cars fitted with run-flats come with onboard tyre pressure monitors, which will notify the driver if there is a flat tyre.
The downside of run-flat tyres is that they tend to give a less comfortable ride than normal tyres because of all the reinforcements. They are also heavier.
Hence, tyre repair kits may be the trend in the years ahead. At least, until manufacturers are able to come up with airless tyres which are comparable to traditional tyres.
Replacing the spare tyre with a tyre repair kit reduces weight by a few kilograms. But if you consider the space previously devoted to stowing a spare tyre, the weight saving is more significant. In any case, most spare tyres are not full-size tyres and are meant to be only a temporary fix.