Most first orders from a new distributor are mixed: two or three truck patterns, a few passenger sizes, sometimes a second brand. The quotation is easy. The loading plan is where the money is.
Start with the box. A 20GP gives you roughly 5.9 m of internal length, 2.35 m of width and 2.39 m of height, about 33 cubic metres. A 40HQ gives you roughly 12.0 m by 2.35 m by 2.69 m, about 76 cubic metres. That is more than double the volume, which is why a 40HQ is usually the better box once your order passes a certain size — but only if the weight stays legal.
Tires are light for their volume, so most mixed tire containers run out of space before they run out of payload. That is the opposite of most cargo, and it changes the planning: you are filling a shape, not watching a scale.
Three things decide whether the load works.
One, truck tires and passenger tires cannot be stacked the same way. Truck tires are normally stood upright in rows, and the rows have to be braced so they do not walk during the voyage. Passenger tires are usually nested or stacked in columns and take up far less floor space per unit of value. Mixing the two means planning each block separately and leaving access for lashing.
Two, the order of loading decides the order of unloading. Put the sizes your customer needs first near the doors. If a mixed container arrives with the fast moving sizes buried behind a block of slow movers, the distributor pays for handling twice.
Three, the pattern mix has to match the quantity per pattern. A minimum of fifty tires per pattern sounds small until you try to fit six patterns into a 20GP and discover that three of them no longer divide evenly into the space left.
The practical way to plan it: send us a list of sizes, patterns and quantities. We lay the sizes out against the container's internal dimensions, come back with a loading plan and an FOB price for that exact mix, and tell you if a 40HQ is worth the extra freight. No one can quote a mixed container accurately from a single size.