The ropes or belts on a traction elevator are the single component holding the car up, and yet most building owners never think about them until a service report shows up recommending replacement. Knowing what actually triggers that recommendation, how the correct rope specification is chosen, and what factors change the scope of the job puts you in a much stronger position than simply having whatever contractor hands you signed off on.

What Actually Triggers Replacement
Rope replacement in a traction elevator is not a judgment call left up to a technician’s opinion, it follows specific discard criteria written into the ASME A17.1 code. On winding drum machines and traction systems alike, ropes have to be replaced once the number of broken wires in the worst section of the rope crosses a defined threshold, generally somewhere between 12 and 18 broken wires per rope lay when they are spread evenly across the strands, or as few as 6 to 12 when the breaks are concentrated in one or two strands. More than one valley break in a single rope lay is also an automatic replacement trigger on its own. Diameter reduction is the other major factor. Once a rope’s actual diameter has worn down by roughly 6 percent from its original nominal size, it is considered past the point of safe use, regardless of how the wires themselves look. Corrosion, waviness, and localized damage from contact with metal edges or deformed sheave grooves round out the rest of what a qualified inspector is checking for during a rope or belt inspection.

Choosing the Correct Wire Rope Specification

Selecting the right replacement rope is a full engineering decision, not just a matter of matching diameter. ASME A17.1 sets a minimum factor of safety for suspension ropes that scales directly with rope speed, running from roughly 7.6 at the slowest passenger elevator speeds up to nearly 11.9 at the highest, with slightly lower minimums permitted for freight service. That safety factor, combined with the weight of the car and counterweight and the elevator’s rated load, is what determines how many ropes are needed and what breaking strength each one has to carry. Code sets a floor of three ropes for a traction elevator and two for a drum type machine, with at least two ropes required on the counterweight side whenever a counterweight is used.

Rope construction matters just as much as the safety factor calculation. Traditional elevator hoist ropes are most commonly built to an 8×19 class, meaning eight strands of roughly nineteen wires each, paired with a fiber core rather than a steel core. That combination gives the flexibility needed to wrap repeatedly around a relatively small traction sheave without fatiguing, while the eight strand cross-section increases the rope’s contact area with the groove and improves traction compared to a stiffer construction. Independent wire rope core versions trade some of that flexibility for added strength and heat resistance, which has its place in specific high load applications, but a steel core rope is not automatically an upgrade for every building.

The detail that catches building owners off guard is that a new rope has to be compatible with the sheave it will run on, not just with the elevator’s rated load. Code requires the sheave’s pitch diameter to be at least 40 times the rope’s diameter for suspension ropes, and at least 32 times the rope’s diameter for compensation ropes. This ratio between sheave and rope diameter protects the rope from bending fatigue every time it travels around the sheave. If a replacement rope is a different diameter or construction than what was originally installed, that ratio and the groove profile both need to be rechecked before the new ropes go in, not after. Installing the wrong rope specification on a mismatched sheave is one of the more common and costly mistakes in a rope replacement job, since it can quietly shorten the new rope’s service life long before anyone notices a problem.

Equal Tensioning and Rotation Prevention at the Terminations

Selecting the right rope is only half the job, getting it tensioned correctly is just as important. ASME A17.1 requires equal tension to be maintained across every rope in a set, and it defines equal in specific terms, the lowest tension measured across the ropes has to fall within 10 percent of the highest tension measured. When the ropes are unevenly tensioned, the car’s weight is not shared as designed, which means that more than the intended load is carried by one or two ropes while the others are left under loaded. That imbalance causes wear to be accelerated unevenly across the set, uneven wear patterns to be created in the sheave grooves, and the service life of the entire rope set to be shortened rather than just that of the overloaded rope. Best practice is to check tension at installation, again after four to six weeks of operation, again at six months, and then annually going forward, since ropes continue to seat and stretch during that initial break in period.

Rotation prevention at the terminations is the other half of that same equation. When rope tension is checked or adjusted, the wedge sockets or other terminations at the top of the hoistway have to be secured against rotating during operation. A termination that is free to spin will let the rope itself begin to untwist under its own working tension, which throws off the tension balance that was just corrected and weakens the rope’s construction over time. The code specifically recognizes antirotation devices for this purpose, and they should be incorporated into the suspension system in any competent installation rather than having the sockets kept in place by friction alone. This is a detail that is easy to overlook on a rope replacement job that otherwise looks complete, and it is worth confirming directly with whichever contractor performs the work.

Wire Rope Versus Coated Steel Belt

Traditional steel wire rope has been the standard for traction elevators for well over a century, and it remains the stronger choice for heavy duty and high load applications. Coated steel belts, a newer technology built from multiple high strength steel cords embedded in a polyurethane coating and formed into a flat profile, have become increasingly common in machine room less and mid to high speed installations. The flat design gives the belt a larger contact area with the traction sheave, which spreads friction and stress more evenly, runs quieter with less vibration, and does not require the ongoing lubrication that wire rope needs. Over the long run, that more even stress distribution tends to give belts better fatigue resistance and a longer service life in typical mid rise and high rise applications, though wire rope still has the edge in raw load capacity for the heaviest duty systems. If your building is weighing a full modernization rather than a like for like rope swap, this is a decision point worth discussing directly with your contractor rather than assuming one option is simply the upgrade.

Fire Protection and Sunlight Exposure Requirements for Coated Belts

If your building is considering a coated steel belt, two code-driven questions need to be answered before that belt is specified, and both come from outside ASME A17.1 itself. The first is a fire protection question. Under NFPA 13, sprinklers are required at the top and bottom of an elevator hoistway where a combustible suspension means is used, with noncircular elastomeric-coated or polyurethane-coated steel belts being specifically identified as that type of combustible suspension. The code carves out an exception, though: that sprinkler requirement does not apply if the belt itself has been tested and carries not less than an FT-1 rating under the UL 62 vertical flame test, now succeeded by UL 2556. In practical terms, that means a hoistway without a sprinkler is only code-compliant with a coated steel belt installed if the belt’s FT-1 rating is documented in writing by the manufacturer and confirmed in the submittal, not simply assumed because the belt looks similar to one used elsewhere. This is a coordination point between the elevator contractor and the fire protection engineer of record, and it belongs on the table before the belt is ordered, not discovered during inspection.

The second question involves sunlight and heat, and it becomes relevant whenever a hoistway includes glass, which is increasingly common in scenic and observation elevator installations across Las Vegas hotel and resort properties. ASME A17.6 Part 3, which governs noncircular elastomeric-coated steel suspension members, requires under Section 3.4.1.3 that the durability, flexibility, and traction requirements established by the belt manufacturer or user be met by the elastomeric coating. Unlike the requirements for aramid fiber ropes under Part 2, no specific temperature or ultraviolet exposure limit is specified for these coatings, while protection from weather and ultraviolet light and functional performance up to 121 degrees Celsius are explicitly required for aramid fiber ropes. Because Part 3 leaves that durability specification to the manufacturer rather than fixing a number in the code itself, the responsibility falls on the specifier to confirm, in writing, that the coating selected for a glass hoistway or any hoistway with direct sun exposure carries documented ultraviolet and heat resistance suited to that condition. Design guidance in the vertical transportation industry treats this as a real and recurring issue, not a theoretical one: polyurethane jackets exposed to sustained direct sunlight are prone to surface crazing over time, which lets moisture reach the steel cords underneath, and sustained hoistway temperatures well above normal ambient conditions accelerate that breakdown. A glass hoistway is a legitimate design choice, permitted under ASME A17.1 when the glazing itself is laminated and meets the applicable glazing standard, but the belt specification for that hoistway needs to match the exposure it will actually see.

What Affects the Scope of the Job

The scope of a rope or belt replacement varies quite a bit from building to building, and it is shaped by several concrete factors. A rope only replacement, covering labor, the new ropes, and the several weeks of re-stretching and tension adjustment that follow installation, is a smaller undertaking than a job where the sheaves also need to be replaced, since worn sheaves with grooves that have gone too deep or uneven will destroy new ropes within months if they are not addressed at the same time. Hydraulic elevators are a different story altogether, since hydraulic ropes do not carry the full weight of the car the way traction ropes do, which keeps that scope of work considerably smaller. Beyond the basic rope versus rope-and-sheave decision, taller buildings need longer ropes and more labor time to run and terminate them correctly, and buildings with limited rooftop or machine room access sometimes require additional rigging to get the job done safely, which is a real consideration for many Las Vegas Strip and downtown high rise properties. Whether the governor rope is included in the scope matters too, since it is a separate rope with its own inspection criteria and is easy to overlook if it is not called out explicitly in a proposal. The elevator is fully out of service for the duration of the work, so scheduling around building occupancy, and in a single elevator building arranging temporary access accommodations, is part of the real scope of the project even when it does not show up as a line item on the invoice.

It is also worth knowing that under Nevada’s elevator regulations, replacing ropes or belts with parts of equivalent material, strength, and design to the originals is treated as routine maintenance and generally does not require a separate permit. That changes, however, the moment the replacement involves a different design, such as switching from conventional wire rope to a coated steel belt system, since that kind of change is treated as an alteration and does require a permit filed with the Mechanical Compliance Section by a licensed elevator contractor, along with a satisfactory inspection before the change is finalized.

What to Ask Before You Approve the Work
Before signing off on a rope or belt replacement proposal, ask for the most recent rope inspection report along with the actual caliper measurements showing diameter reduction, not just a general recommendation. Confirm explicitly whether sheave replacement is included in the scope and, if it is not, ask why, since installing new ropes on worn sheaves is a short term fix that costs more in the long run. Ask what rope construction and diameter is being proposed and whether it matches the sheave’s pitch diameter and groove profile, and confirm that the contractor will verify equal tension across the full set and install proper antirotation devices at the terminations rather than treating those steps as an afterthought. Get proposals from at least two qualified contractors so you have a real basis for comparison, and check your maintenance contract to see whether rope or belt replacement is already covered under your existing agreement before treating it as a separate project.

Partner With AR Elevator USA
Rope and belt replacement is one of the more significant repairs a traction elevator will need over its service life, and getting the specification, tensioning, and termination details right the first time protects both your budget and your building’s uptime. AR Elevator USA provides thorough rope and belt inspections, correctly specified replacements, and full code compliant installation for buildings across the Greater Las Vegas Area.

Ready to find out whether your elevator’s ropes or belts need attention?
Contact AR Elevator USA today for a professional rope and belt inspection and detailed proposal.

Phone: 702-810-2757 | 702-463-6430
Written By Eng. Houssam Zammam
An Elevator Portfolio Manager