Caster Bearings: Ball vs Roller vs Plain Bore — How to Choose

When buyers spec a caster, they fixate on the wheel diameter and the load rating. Fair enough. But the part that decides whether the trolley pushes like it is on ice or pushes like it has concrete boots on is not the wheel size — it is the bearing inside the wheel hub. A cheap caster with the same diameter and same load rating can take twice the push force of a good one, and nine times out of ten the difference is the bearing.

This guide walks through the bearing types you will actually find on industrial casters — ball bearings, roller bearings, plain bores and bronze bushings — what each one feels like on the floor, and which one belongs on your trolley.

What Is a Caster Bearing, Exactly?

A caster bearing sits between the wheel hub and the axle. It lets the wheel spin freely around a fixed bolt. Without it, the wheel would slide on the axle instead of rolling — that is how hard a trolley feels with a seized bearing. The bearing also handles the load: the weight of the cart presses down through the wheel, through the bearing, onto the axle. A bearing that is too small for the load will either lock up instantly or wear out in months.

There are two bearing locations on every swivel caster: one in the wheel hub (the wheel bearing) and one in the swivel raceway (the bearing between the bracket legs). This page is about the wheel bearing — the one that decides push effort.

The Four Main Caster Bearing Types — Side by Side

Bearing Deep Dive

1. Ball Bearing — The Default for Push Carts

Ball bearings are exactly what they sound like: steel balls sandwiched between two races, rolling with almost no friction. This is the bearing you want on any trolley that a human pushes by hand. The push effort stays low even when the cart is loaded, and the wheel starts rolling with barely any force. Our EH08 heavy-duty line uses sealed ball bearings on the 125 mm PU wheels, which is why a 250 kg-per-wheel caster still rolls easily on a flat floor.

Watch out: Cheap ball bearings are unsealed and pick up dust and water. Sealed bearings cost a little more but last far longer in dirty warehouses.

2. Roller Bearing — For Heavier, Longer Runs

Roller bearings use cylindrical rollers instead of balls. They spread the load over a longer contact surface, so they carry more weight than a ball bearing of the same size. The tradeoff: roller bearings feel slightly stiffer at the very start of a push (the rollers need to “line up” before they roll smoothly). They are the right pick for motorized carts, long conveyor-style runs, and loads where ball bearings would be undersized.

3. Plain Bore / Hole — No Bearing At All

A plain bore is literally a hole through the wheel, with a bolt sliding through it. There is no rolling element — the wheel rubs directly on the axle. It is cheap, it is simple, and it feels terrible under load. Plain bores belong on light furniture casters and occasional-use equipment. On an industrial trolley pushed four hours a day, a plain bore wheel will seize, wear oval, and get noisy within months. If you are building anything that runs more than once a week, do not spec a plain bore.

4. Bronze / Oil-Impregnated Bushing — For Dirty or Hot Places

A bronze bushing is a sleeve pressed into the wheel hub. Oil-impregnated bronze holds lubricant inside its pores, so it keeps working in environments where a ball bearing would fail — wet washdown areas, high-temperature ovens, or dusty foundries. It does not roll as freely as a ball bearing, but it survives where sealed bearings rust or seize.

Why the Swivel Raceway Matters Too

Remember: on a swivel caster there are two bearing systems. The wheel bearing decides how hard the cart is to push forward. The swivel raceway bearing decides how easily the caster turns when you steer. A caster with a great wheel bearing but a cheap swivel raceway will still feel stiff when you try to corner — the wheel rolls fine, but the whole caster fights the turn.

On our EH08 series, both the wheel hub and the swivel raceway use ball bearings, and the swivel raceway is packed with grease at the factory. That is why a loaded trolley steers easily, not just rolls easily.

Five Common Mistakes Buyers Make

1. Ignoring the bearing on the spec sheet. Two casters with the same diameter and same load rating can use completely different bearings. Ask what is in the hub.
2. Specifying a ball bearing where a roller is better. Ball bearings feel great at low load but can brinell (dent) under very heavy static loads. For loads over 500 kg per wheel, rollers are safer.
3. Using plain bore on an industrial trolley. It saves money on day one and costs you in push effort and replacement wheels within a year.
4. Forgetting sealed vs unsealed. In a wet or dusty warehouse, an unsealed ball bearing dies fast. Pay for sealed bearings.
5. Specifying the same bearing for all four wheels. It is fine to use a cheaper bearing on the rigid (fixed) wheels and a better one on the swivel wheels — the swivel wheels do most of the steering work.

How to Choose — A Quick Decision Flow

1. Is a human pushing the cart by hand? Yes → ball bearing. That is the whole answer for 80% of indoor trolleys.
2. Is the load over 500 kg per wheel, or is the cart motorized? Yes → roller bearing.
3. Is the environment wet, dusty, or hot? Yes → sealed ball bearing if it is moderately dirty, bronze bushing if it is really hostile.
4. Is the cart light-duty and used once a week? Yes → plain bore is fine and cheap.

Worked Example

A 600 kg platform trolley, pushed by one warehouse worker 6 km a day on sealed concrete. Four wheels → 600 ÷ 4 = 150 kg per wheel. Add 30% safety margin → 195 kg per wheel. The load is well within ball-bearing range, and the worker pushes it by hand all day. Pick a 5 inch (125 mm) iron-core PU wheel with sealed ball bearing — exactly the EH08-11-125S-402 we spec on our product page. A plain bore would feel like pushing a brick. A roller bearing would be overkill. Ball bearing is the sweet spot.

How Globe Caster Helps

Globe Caster — Foshan Global Caster Co., Ltd, Guangdong, China — has been making casters and castors since 1988. Our 156,000 m² facility runs in-house stamping, injection molding and PU pouring, and we assemble and pack every caster under one roof. We stock 600+ standard SKUs across ball-bearing, roller-bearing and plain-bore configurations, and can mix bearing types in one container if your rigid and swivel wheels need different specs. Typical lead time 30 days, 12-month warranty, ISO 9001 and ISO 14001 certified.

Not sure which bearing fits your cart? Send us the load per wheel, the push method (manual or motorized), and the environment. We will recommend the bearing type and send samples so you can feel the difference on your own floor.