Suspension means are the last thing between the car and gravity, and the easiest thing to inspect badly: a glance at the visible section in the machine room tells you almost nothing about the part that spends its life bending over the sheave.
What to examine, and where
| Check | Where | What it indicates |
|---|---|---|
| Broken wires / belt damage | Full length, especially over sheaves and at terminations | Localised damage = mechanical cause; widespread = age or fatigue |
| Wear pattern (oval, flat, ridged) | Rope crown over the sheave path | Misalignment of sheave or diverter, wrong groove profile |
| Tension equalisation | At the termination / equaliser | Uneven load sharing, which accelerates the worst rope |
| Corrosion and lubrication | Hoistway environment | Dry or corroded ropes wear the sheave and each other |
| Rope diameter / belt thickness | Representative samples | Measured against the maker’s retirement value, not a remembered number |
| Terminations and shackles | Car and counterweight | Correct hardware, no field-modified terminations |
Reading the wear pattern
- Wear concentrated in one band of the rope: the sheave groove and the rope are not aligned through the travel – check sheave alignment and the guide system.
- One rope worn far more than its neighbours: tension imbalance or a groove cut differently in the sheave.
- Uniform light wear with correct diameter: normal service – keep monitoring the trend.
- Belt with visible rib damage or cracking: treat as a maker-defined retirement condition, not a “monitor it” condition.
Retirement criteria
Retirement values depend on construction: steel rope criteria (broken wire counts over a stated length, diameter reduction, corrosion, distortion) differ from coated flat belt criteria, and both are set out by the equipment maker and the applicable code. Two rules keep you out of trouble:
- Use the maker’s criteria for the specific product – do not apply a general steel-rope rule to a belt.
- Retire the whole set when the criteria call for it. Replacing one rope of a matched set creates a tension and stretch mismatch that damages the new rope too.
Safety: rope and belt work is done above the car, in the pit, or at the machine. Apply lockout and confirm zero energy, and never work under an unsupported car. Unequal rope tension can move the car when the load is transferred.
Related: drives and motors, maintenance program, and forum threads on rope wear.