XL tyres - what are they? SUV tyres on sports cars?

[Panamax]

The superficial meaning of XL may be clear but what's the actual difference between and XL tyre and a non-XL tyre and does it matter?

My understanding is the codes on the side of the tyre, such as 245/45 R20 W (103) contain the full specification of the tyre with (103) being its load rating. What does an XL description add?

The significance of my question is that powerful modern sports cars tend to require tyres in sizes that are more usually sold for use on big, heavy SUVs and are therefore XL rated. i.e. you're likely to be fitting XL tyres on a non-XL vehicle.

[Dave Hedgehog]

XL tyres are reinforced so can take higher loads / weight

If i recall if your vehicle requires them and you fit standard ones it can be an out for the insurance company

[Scrump]

XL is usually a higher load rating for the same size tyre.
My 911 requires XL rated rear tyres as standard.

[RazerSauber]

Extra Load is my understanding. Often found where large forces are present. Vans, performance cars, stuff like that.

[Sheepshanks]

Panamax said:

My understanding is the codes on the side of the tyre, such as 245/45 R20 W (103) contain the full specification of the tyre with (103) being its load rating. What does an XL description add?

In that size, 103 is XL. 99 in the non-XL spec.

So I see your point - why even mention XL? It would make sense if there was a non-XL 103 load index tyre, but there isn't.

Another odd thing is that for an XL tyre to achieve the same normal load carrying capacity as a non-XL tyre it needs to have a slightly higher pressure. XL tyres only come in their own at high pressures.

Having said that, I think it was on here that someone who reviews tyres said some manufacturers use the same carcass anyway - the different ratings are basically just a marketing thing.

[Panamax]

Sheepshanks said:

I see your point - why even mention XL? It would make sense if there was a non-XL 103 load index tyre, but there isn't.

Yes, that's exactly what I've encountered and don't understand.

My modest logic is SUVs need tough tyres because they're heavy whereas powerful sports cars need tough tyres because they can work them hard. What I haven't managed to understand is how "XL" adds anything to "103". I guess if Mr/Mrs Average Customer doesn't understand the coding on the tyre they might grasp that "XL" in the marketing blurb sounds right for their SUV.

[trevalvole]

Some years ago, on various MX-5 forums, there was a tyre supplier who pointed out that an XL tyre is one that can take the higher air pressure to support additional weight and that any additional sidewall strength has little role in supporting this weight. This makes sense to me as if you can squash a sidewall with your fingers, how much support will it give to 400kg per corner?