Spare Wheels

As readers would be aware many new car manufacturers are not providing a normal spare wheel and tyre with new cars. Instead the “spare” is a smaller width wheel rim with a light cheap tyre that can not be driven any great distance. In fact the handbook often states that the “spare” is not to be driven more than 75Km and is provided to enable the driver to get to a Service Station to have the normal wheel and tyre repaired and refitted.

A few manufacturers in Europe have extended this basic concept further by equipping their new cars with “drive on flat” tyres and eliminating the spare wheel altogether. The “drive on flat” tyres are a new innovation that are manufactured with an inner rubber ridge that projects toward the tyre inner ply and extends around the rim circumference on both sides of the tyre. These tyres are mounted on specially designed wheel rims that provide support for the inner ridges. When normally inflated the inner ply clears the ridge and the tyre gives a vehicle ride with normal tyre sidewall flex.

If the tyre deflates the tyre sidewall bulges under the vehicle weight and the tyre inner ply makes contact with the ridges on both sides of the tyre. This prevents the tyre from collapsing and allows the vehicle to be carefully driven on the “flat” tyre. The manufacturers recommend no more than 100km is completed under this condition and that the tyre is repaired as soon as possible.

Editors Note: When you have no spare what other choice do you have?