The Rope Itself · STRETCH
Rope Stretch — Why New Ropes Grow
Every new rope settles in — plan for it, don’t fight it.
New wire ropes lengthen in service. Constructional stretch — the strands and core bedding down under load — permanently removes the manufacturing “looseness” in the rope over its first weeks and months; elastic stretch remains for life, spring-like and load-dependent. Managed properly with re-tensioning and shortening visits, stretch is routine; ignored, it becomes buffer clearances and levelling faults.
The explainer
Watch how it works.
Schematic · loops automatically
1A new rope holds hidden slack
Strands and core sit proud of their final geometry — manufacturing looseness waiting to bed down.
2Load beds the construction in
Early cycles seat the strands and compress the core; the rope permanently lengthens.
3The curve flattens
Constructional stretch is front-loaded — steep in early service, settling toward a stable length.
4Elastic stretch stays forever
Rope remains a spring: length varies with load, recovering each time — this part is normal, designed-for behaviour.
5Shorten, re-tension, done
A planned visit takes the growth back out at the terminations and equalises tensions — stretch managed, margins restored.
How it works, plainly
A freshly closed rope contains geometric slack: strands not fully seated, core not fully compressed. Early load cycles squeeze this out — the helices tighten, the core beds, and the rope permanently lengthens by a small percentage of its length. On a tall installation, a small percentage is a large number of millimetres arriving at the hitch plates.
Constructional stretch is front-loaded: fastest in the first days of duty, tapering as the construction settles. Fibre-core ropes generally settle more than steel-core; high-performance compacted constructions settle less than conventional ones. Manufacturers publish expected ranges — good installers plan the follow-up visit before the ropes are even fitted.
Elastic stretch never leaves: rope is a very long spring, extending with load and recovering when unloaded. Designers account for it; what service must manage is the permanent constructional component — by re-checking tensions after bedding-in, and shortening ropes at the terminations (wedge sockets make this quick) so the counterweight keeps its designed runby and the car keeps its levelling.
Where this matters
On the job
- Planning post-installation shortening visits
- Explaining early levelling changes after re-roping
- High-travel installations where percentages become metres
Standards & references
| Reference | Covers |
|---|---|
| ISO 4344:2022 context | Rope properties including elongation behaviour |
| Manufacturer data | Expected constructional stretch ranges per construction |
Re-Ropes builds the stretch visit into supply-and-fit programmes: tensions equalised at fit, then re-checked and ropes shortened once bedding-in has done its work.
How much will new lift ropes stretch?
Constructional stretch is typically a fraction of a percent up to around one percent of rope length depending on construction — fibre-core conventional ropes at the higher end, compacted high-performance ropes lower. On a 100 m rope, even 0.5% is half a metre: this is why shortening visits exist.
When should ropes be shortened after a re-rope?
Once the front-loaded settling has substantially completed — commonly some weeks into normal service, sooner on heavily used installations. The trigger is measured: runby and levelling tell you when the growth needs taking out.
Is stretch a defect?
No — constructional stretch is inherent behaviour, not a fault. The defect is unmanaged stretch: uneven tensions, lost runby and levelling faults that were entirely predictable at installation time.
Lift Industry Specialists
Questions about stretch on your installation?
Describe the lift and the symptom — an engineer who has seen it before will tell you what it means and what it costs to fix.