When choosing caster wheels for a factory, the first question is usually "which tread material is best?", because the tread determines load capacity, service life and the effect on the factory floor. This article compares the 3 most common tread materials — PU (polyurethane) with a cast-iron core, black rubber and nylon/plastic — so you get it right the first time.
Quick Comparison Table
| Property | PU with cast-iron core | Black rubber | Nylon |
|---|---|---|---|
| Load capacity | Very high | Medium | High (but hard) |
| Floor marking | Non-marking | Leaves black marks | Non-marking |
| Oil/chemical resistance | Good | Degrades easily | Good |
| Noise/vibration | Quiet, cushioned | Quiet | Noisy, hard |
| Kind to epoxy floors | Excellent | Fair | Scratches the floor |
Cast-Iron-Core PU Wheels — The Choice for Heavy-Duty Work
A PU wheel is a dense synthetic tread cast onto a steel core. Its strength is "real load capacity", because the cast-iron core (especially the 5.5 mm thick version) won't deform or twist under heavy loads, while the outer PU tread stays soft enough to run quietly without damaging the floor.
- Load capacity up to 350 kg per wheel (1,400 kg per set for the 6-inch model)
- Leaves no black marks on epoxy floors — ideal for food, pharmaceutical and electronics factories
- Resists oil and chemicals better than natural rubber
Black Rubber Wheels — Cheap, but at the Cost of Marks and Lifespan
Black rubber wheels are cheap and roll softly, but their clear weaknesses are that they leave black marks on the floor and degrade when exposed to oil. In clean areas or around chemicals their service life is short, becoming a hidden cost through frequent replacement.
Nylon Wheels — Strong, but Noisy and Hard on Floors
Nylon carries high loads and resists chemicals, but it is very hard, so it is noisy, transmits vibration and easily scratches epoxy floors. It suits rough concrete better than the smooth floors of modern factories.
Summary: Which Should You Choose?
If lowest cost matters most and marking isn't a concern, black rubber will do. But if you need heavy load capacity, floor protection, no marking and a long service life, cast-iron-core PU wheels are better value in the long run, because they need replacing less often and don't create floor repair costs.