Hose and tube fail on spools in ways that cable does not. Cable stretches; hose kinks. Cable takes a set; tube ovalises. Both failure modes are decided by the same variable — the radius the product is held at — which means both are largely a core diameter decision made before the spool exists.
Kinking
A hose has a minimum bend radius below which the wall collapses on the inside of the bend. Unlike cable, which may recover or may not, a kinked hose is permanently damaged: the reinforcement is deformed and the hose will fail at that point, usually much later, in service.
The tightest bend a hose sees in the whole operation is at the core on the first layer. If the core diameter is below twice the hose’s minimum bend radius, you are kinking the first layer as you wind it — and you will not find out until it is installed.
The rule is simple and frequently ignored: core diameter should be at least twice the minimum bend radius for the hose, with margin. Where that makes the core impractically large, the product should not be spooled and should ship in coils instead.
Ovalisation
Thin-wall tube does not kink so much as flatten. Under the pressure of the layers above it, and under winding tension, a tube cross-section can deform from round toward oval. That changes its flow characteristics and, worse, it can make it impossible to push a fitting through.
Ovalisation is driven by compression, which means it is driven by how many layers are above and how much tension they are under. Two mitigations: keep winding tension moderate, and limit the number of layers. A wider spool with fewer layers is much kinder to thin-wall tube than a narrow one with many.
Tension is lower than you think
Operators used to cable often wind hose and tube at cable tensions. Hose does not need it and does not want it. Tension only needs to be enough to lay the product on neatly and keep it there; more than that contributes to ovalisation and puts the inner layers under pressure they will hold for months.
If in doubt, wind looser than feels right and check the pack after a day. It is easy to add tension and impossible to undo the damage.
Storage time matters more
Hose and tube are viscoelastic — they continue to deform under load over time. A pack that is perfectly round when wound can be measurably ovalised after three months in a warm warehouse. This is why the storage interval belongs in the specification conversation alongside tension and core size.
For long storage, reduce the layer count and consider rotating stock so nothing sits at the bottom of a deep pack indefinitely.
Reinforced hose is different
Wire- or textile-reinforced hose is stiffer and more kink-resistant than unreinforced hose, and it has more spring-back. That changes the handling rather than the geometry: reinforced hose stores energy and should be restrained until it is on the machine, for the same reason rope should be.
What to tell a supplier
- Product type, outside diameter and wall thickness
- Minimum bend radius from the product specification
- Whether it is reinforced
- Expected storage time before use
- Whether it will be paid off at speed or by hand
With those, the core diameter and the layer limit follow directly. Without them, you are guessing at the two variables that decide whether the product arrives usable.
And if the geometry does not work — if a safe core leaves no usable capacity — the honest answer is coils rather than spools. It is worth hearing that before you tool a spool.