English
PU or Nylon or Rubber or TPR? Choosing the Right Caster Wheel Material
Created on 10.13
The question comes in almost every second enquiry, and it comes in the same shape. The buyer has already settled the size and the load rating, and then asks the last part: PU or nylon?
It's the right question to ask, because the material is what decides how the caster behaves on your floor. Not the load figure. A 200 mm wheel rated at 250 kg will roll beautifully in one plant and be a complaint waiting to happen in the next one, on the same load, with nothing changed except the wheel material.
We make all of them, so we have no favourite to push. Here is how we explain the choice to buyers.
The core carries the load. The tyre does everything else
Most casters are built the same way. A harder material carries the load and holds the bearing, and a softer tyre sits on the outside and touches the floor.
That hard part is usually polypropylene, iron or aluminium. On some wheels there is no separate tyre at all: the whole wheel is one piece of hard material, which is why solid PP and nylon wheels behave so differently from rubber or PU.
Two things follow from that. First, the load rating describes the whole build, the core, the bearing behind it and the rubber compound on it, not the ride. Second, everything the operator notices, the noise, the effort of pushing, the marks on the floor, the wear, comes from the material on the outside.
Our own range shows why you can't judge a wheel by its size. A 200 mm wheel can be rated 210 kg, 330 kg or 500 kg. Between those three the core changes, the rubber compound changes and the bearing changes, all three at once. So don't carry a load figure across from a wheel that merely looks similar. The same diameter does not mean the same job.
Rubber: quiet, grippy, and kind to floors
Rubber on a polypropylene or iron core is the combination we quote most for outdoor and kerbside work, and for good reason. It grips a wet pavement, it runs quietly, and it doesn't mark a floor. Under normal use it wears well.
The one thing to watch is flat spotting. A caster that stands loaded in the same position for months can take a flat spot on the tyre. On a route where the wheel keeps turning, that doesn't happen.
Choose rubber when the floor is smooth or moderately rough, when noise matters, and when grip and quiet running are worth more to you than the lowest possible price.
TPR: the same feel for less money, indoors
TPR behaves much like rubber and costs less, which is why it is popular on light and medium duty casters.
It is not simply a cheaper rubber. Compared with rubber it dislikes sustained heat and concentrated loads. TPR earns its place indoors, on trolleys and light equipment, where the load is moderate and the floor is clean and dry.
PP and nylon (PA): the hard wheels
Polypropylene and nylon are the two hard materials we use most, and they sit at two different price points.
PP is the cheapest of the two. It is light, it doesn't mark floors, and it handles moderate loads indoors. What it doesn't take well is abrasion and impact. On rough ground a PP wheel wears faster, and a heavy drop can crack it. It belongs on light and medium duty equipment used indoors.
Nylon (PA) is harder than PP and far more wear resistant. It carries more load in the same diameter, stands up to oils and chemicals, and rolls with very little resistance on a smooth floor.
MC nylon is a separate grade, not another word for nylon. It is cast rather than extruded, and we only use it on extra heavy duty wheels, where the load and the impact go beyond what a standard nylon wheel will take. For normal duty, standard nylon is the right answer, and the cheaper one.
What nylon does not do is absorb anything. It transmits shock straight into the load and the bracket, it is noisy on hard floors, and on soft flooring it can leave marks that rubber or PU would not.
Cast iron: for heat and the heaviest loads
Cast iron wheels belong to ovens, foundries and kilns. They take heat that would destroy every other material on this page, and they carry enormous loads.
They are also heavy, and they will damage a soft floor. If your application doesn't involve heat or extreme load, cast iron is usually the wrong answer.
PU: the easiest to push, and the most load per diameter
Polyurethane rolls more easily than rubber and TPR, and it carries more weight at the same wheel diameter. That is why it turns up on heavier equipment and on anything that gets pushed a long distance.
It also resists oils, grease and abrasion well, and it doesn't mark most floors. In our experience it produces the fewest complaints on mixed industrial floors.
Two limits are worth knowing. Below roughly -10 °C it stiffens and stops being the easy-rolling option. And in hot, permanently wet conditions, some grades of PU will break down over time, so the grade matters as much as the material name. When a buyer tells us the wheel will live in a wash-down area, we ask about temperature and chemistry before we quote.
The floor is the real specification
When a buyer sends us load and diameter but no floor, we ask for a photo. The floor decides more than the data sheet does.
Where the caster lives | What we usually recommend |
Clean indoor floor, noise matters | Rubber on a polypropylene or iron core |
Outdoor use, wet ground, rough paving | Rubber on a polypropylene or iron core |
Wash-down, food or medical environments | Nylon, or PU with a sealed swivel |
Heavy loads, long pushes, mixed concrete | PU on an aluminium or iron core |
Rough concrete outdoors, noise not important | Nylon |
Cold store below -10 °C | Nylon or cast iron |
Oven, foundry, kiln, hot surfaces | Cast iron |
Light indoor equipment, price driven | PP |
Two sites, one part number
The expensive mistake is not picking the wrong material. It is using one material for two jobs.
A supermarket floor and a construction site look similar on a purchase order, because both lines read 200 mm and both read the same load. Put the same castor on both, and one of the two will be back as a complaint inside a year. On the smooth floor the hard wheel is noisy and marks the tiles. On the gravel the soft wheel is worn through.
If you buy for more than one site, split the line. Two part numbers cost you a little admin. A field complaint costs you the account.
What we check before a batch ships
Material claims are easy to make, so we test rather than describe. Every batch goes through dynamic load testing before it leaves the factory, and the brackets go through salt spray testing in our own chamber. Our 200 mm waste container wheels also carry a GTS compliance certificate that runs to May 2028, and we keep it renewed.
If your market is European and you supply mobile containers, raise EN 840 at the enquiry stage. The castors are part of what gets tested against that standard, and a supplier who knows the standard will bring it up before you do.
What to send us
Send the same 6 numbers we ask every buyer for, and you will get a usable answer first time. Equipment or container size. Weight when loaded. Wheel diameter. Bolt hole spacing or plate size. The surface it runs on. Annual quantity.
For a material question, add one photo of the floor. It tells us more than the data sheet does: smooth tiles, sealed concrete, exposed aggregate, gravel, drains and thresholds. If the environment matters, say so as well, whether that is wash-down, temperature, chemicals or outdoor storage.
With those, we can answer the question you actually asked. Not just which size, but which material and which core.
Zhongshan VIMA Metal Products has made caster wheels for waste containers, industrial equipment, furniture, stainless steel applications and medical equipment in Zhongshan, Guangdong since 2007. Send us the 6 numbers and the floor photo, and we will come back with a specification and a sample.
Contact
Leave your information and we will contact you.
WhatsApp
E-mail