A buyer sends “please quote 10 mm rope, blue, 220 m coils” to two suppliers and gets back two prices that differ noticeably. Both confirm the line is “10 mm blue PP rope, 220 m coils”. The buyer assumes one supplier is wrong, or is being opportunistic. Usually neither is true. The two lines are genuinely different products, both honestly described as “10 mm blue PP rope, 220 m coils”, and the difference shows up in fields that diameter alone does not capture.
This article walks through those fields. None of them are exotic; they are the fields that the rope specification checklist recommends for an RFQ in the first place. The point of showing them here is to make the consequence visible: what changes when these fields change, and why two like-named lines can carry different prices.
The fields behind “10 mm”
Material
PP, PE, polyester, nylon, cotton, jute, sisal — each has its own cost band, its own UV behaviour, its own stretch characteristic. PP at the same diameter is cheaper than polyester; PE is similar to PP in cost but different in hand feel; polyester is heavier, more UV-stable and more expensive. A “10 mm PP” line and a “10 mm polyester” line are not the same product at any diameter.
For products where the buyer’s program crosses materials, the material has to be stated explicitly. Two suppliers quoting the same diameter but different materials will return prices that cannot be compared.
Yarn form
Yarn form (split-film, monofilament, multifilament, staple) is invisible on most product photos and changes weight per metre at the same diameter.
- A multifilament 10 mm rope packs more polymer into the cross-section per metre than a monofilament 10 mm rope of the same construction.
- A split-film 10 mm rope weighs less per metre than a multifilament 10 mm rope, because the flat film has more air between the fibres.
- The difference is visible on a 220 m coil: a heavier-per-metre line weighs more on the same reel, takes more container space per kilogram, and arrives at a different freight cost.
The yarn form is identified from a short cut of the sample, not from a photo. Without yarn form on the inquiry, the supplier has to guess — and the guess usually lands on the cheapest yarn form, which is rarely the buyer’s incumbent product.
Construction and density
Construction is the next layer. A “10 mm” rope can be:
- 3-strand twisted (the wholesale standard, generally the lowest-density construction);
- Diamond braided (the retail hardware standard, generally denser than 3-strand at the same diameter);
- Hollow braided (lowest-density braid, soft and flexible);
- Solid braided (denser than diamond, used in marine and industrial);
- Double braided (a braid over a core, the densest construction).
Within each construction, the density of the braid or the tightness of the twist changes the weight per metre at the same diameter. A tight braid weighs more than a loose braid of the same construction. A tight 3-strand twist weighs more than a loose 3-strand twist. A “10 mm 3-strand” rope from one supplier is rarely the same weight per metre as a “10 mm 3-strand” from another supplier.
The practical consequence: a tighter, denser line is heavier on the coil, costs more to ship, and has a different hand feel. A looser, less dense line is lighter and cheaper, but it can feel “thin” at the same diameter. Both are legitimately “10 mm 3-strand” on the spec sheet.
Tolerance
Most rope specifications quote a nominal diameter and a tolerance. The industry convention varies — a common tolerance is ± 5 % of nominal, but tighter and looser tolerances exist. A 10 mm rope with ± 0.3 mm tolerance is different from a 10 mm rope with ± 1.0 mm tolerance. The supplier’s quotation can be matched to the buyer’s own measurement only when the tolerance is on the offer.
A looser tolerance line is cheaper; a tighter tolerance line is more consistent on the buyer’s incoming inspection. The right choice depends on the buyer’s downstream process.
Weight per metre and runlength
For twine and light line, the unit is metres per kilogram (m/kg) — the inverse of weight per metre. Two “10 mm PP ropes” of the same material and same construction can have measurably different m/kg values because of the fields above. The buyer’s program may quote against m/kg (baler twine always does — see baler twine sizes and runlength) or against kg per metre, but rarely against diameter alone.
Colour and pigment
Two blue PP ropes of the same nominal diameter can differ in pigment system (masterbatch vs compounded; one supplier may use higher pigment loading for outdoor UV performance). UV-stabilized pigment costs more than commodity colour. The price difference is real and the colour difference is not always visible to the eye, but the UV performance is.
For an outdoor program the buyer should specify UV-stabilized colour and intended service life; the supplier can then propose the pigment system that matches. See best rope for outdoor use.
Packaging
Packaging is part of the cost. A 220 m shrink-wrapped coil is a different cost from a 200 m reel-served coil with a printed sleeve. A buyer comparing “10 mm rope, 220 m coils” between two suppliers should also confirm reel format, sleeve print and master carton — these are not always itemised on the price line but they are on the total cost.
The comparison table that is honest
The reason a side-by-side comparison table across multiple rope types is not on this page is that it cannot be done honestly without source data on the buyer’s own programs. Industry-typical m/kg values for “10 mm rope” depend on material, yarn form and construction; quoting a generic range would be making up a number to fill a table.
What can be said with confidence:
- Two nominally identical 10 mm PP 3-strand ropes from different suppliers can differ in weight per metre by 10 % or more, depending on construction density and tolerance.
- A 10 mm multifilament PE rope weighs more per metre than a 10 mm split-film PP rope of the same nominal diameter.
- A tighter 3-strand twist at the same diameter weighs more than a looser one.
- A UV-stabilized blue pigment costs more than a commodity blue.
These are general observations about how the fields above interact with weight and price. They are not industry-typical numbers — those have to come from the buyer’s own incoming data.
Making two quotations comparable
The single move that makes two “10 mm” quotations comparable is to ask both suppliers for the same five fields:
- Material (named, not implied).
- Yarn form (split-film / monofilament / multifilament / staple).
- Construction (3-strand / diamond braid / solid braid / etc.) and the construction density where it is variable.
- Weight per metre or runlength (kg/m or m/kg).
- Tolerance on the nominal diameter.
Two quotations on those five fields are comparable. Two quotations on diameter alone are not. The buyer’s structured RFQ form walks through the same fields in the same order, with the additional notes for electric-fence line when the program is fence cordage rather than general rope.
A practical first step
When a buyer is unsure whether two like-named lines are the same product, the fastest check is to ask each supplier for a 1 m cut sample (or to send a cut of the buyer’s own incumbent product). The yarn form, the construction density, the weight per metre and the colour are all visible in a 1 m cut, and the supplier’s quotation can be matched against the actual product instead of against a name. The reverse-sourcing procedure for this case is in how to match an existing rope or twine sample.