The Oponeo tyre site says the below on XL tyres, I've got XL Eagle AS2's and they are an excellent all-round tyre with better dynamics and comfort than the old run-flats.
What Benefits Do Reinforced Tyres Bring?
The advantages of reinforced tyres results from their increased load capacity. This includes:
When normal and reinforced tyres are used in the same way, the latter will last longer. XL tyres can travel for a greater total distance without suffering internal damage, even when under intensive use. This applies so long as the vehicle manufacturer’s recommended pressure is being adhered to.
Resistance to mechanical damage caused, for example, by driving at high speeds into the kerb.
Better traction and adhesion properties. The tyre’s greater rigidity ensures stability, more effective transmission of the vehicle’s power to the road surface, better handling on corners, a faster reaction to turns and a greater resistance to additional loads and forces.
What Are The Disadvantages Of Reinforced Tyres?
Of course, there is no such thing as a perfect tyre. All models are a designed and calculated compromise between various parameters and this still applies to reinforced tyres. The more important drawbacks to reinforced tyres are:
Higher noise levels. The tyre certification requirements permit reinforced tyres to produce 1 dB (decibel) more noise than normal tyres.
The use of reinforcement may involve increasing the thickness of the face (under the tread) and shoulder of the tyre. This, in turn, can cause increased rolling resistance and greater fuel consumption.
Reinforcement usually involves an increase in the tyre’s weight and mass, which again leads to higher fuel consumption.
Modifications may lead to a lowering of the driving comfort, when compared to using normal tyres, although such differences will be minimal and rarely felt by the driver.
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