Tires: light truck tyre ranges, vehicle designers, truck tyre

Question
Is there a specific range of tyres applicable for light trucks?

Answer
Jerome,

I'm not sure what question you really want the answer to, and I suspect this isn't it.  But if you will allow me some manuvering room, I'll try to explain the situation.  Be aware that there is much more to this subject than I have written here, but it gets really technical, and I don't think you really want to get in that deep.

On every vehicle sold in the US, there is a label that indicates the original tire size and the proper pressure for that size.  This label is commonly called the "Placard".  It is my understanding that this placard appears on pretty much every vehicle, even though that vehicle was never designed to be sold in the US.  The tire size listed on the placard is what the vehicle designer specified as part of his design.  Follow that sizing.  That is applicable for that vehicle.

But to fill in the gaps:  Part of the tire size will be some letters that indicate the nature of the tire design.

For example:  If the size starts with the letters "LT", it is called an "LT metric" and it is designed to a US tire standard that is applicable for "Light Truck" vehicles.   

If the size starts with the letter "P", it is called a "P metric" and is designed to a US tire standard that is applicable for passenger cars.

If the size ends in the letter "C", then the tire was designed to a European tire standard applicable for Commercial vehicles - the functional equivalent of "LT".

There are many more, but this gives you a flavor.

The problem is that there is an overlap in these tire standards, and vehicle designers have a choice as to what tire standard they can chose from.

It is fairly common for small pickups and SUV's to use P metric tires - even though these aren't passenger cars - and that's OK, as the tire design standard has a way of dealing with this - a 10% reduction in load carrying capacity.  

But there is a limit for P metric tires - and the way it seems to work is that 3/4 ton pickups are too heavy to use P metric tires.

However, the "LT"'s and "C"'s do have some fairly small tire sizes available, and they COULD be used on light trucks, but their use is relatively rare.

So to answer your question:  It's a sort of "NO, there isn't a specific range".  It is done generally by load carrying capacity and the vehicle designers pick a tire size that is appropriate.  

But it's also a sort of "Yes", in that light trucks generally fall into a range of weight values - and tires are designed around load carrying capacity.

Hope this helps.