The term can be misleading. One might imagine that reinforced tyres are able to withstand the stresses of rough and stony roads so as to avoid punctures... but in reality, it is quite another matter!
Indeed, reinforced tyres are not intended for off-road use. They are tyres with an increased load capacity. They allow you to drive in good conditions while supporting a higher load due to the mass of the vehicle.
There are several ways to absorb the mass of a vehicle:
- either by increasing the size of the tyre: this increases the volume of air that carries the load,
- or by increasing its pressure.
It is for this second option that reinforced tyres have been designed.
Reinforced tyres, formerly marked REINF on the sidewall (for "reinforced"), are now called XL (Extra Load), as opposed to SL (Standard Load).
The load index of the tyre (which is marked on the sidewall of the tyre) is higher on an XL tyre than on an SL tyre, which means that it is able to support a heavier vehicle.