Fixed bracket with PP hub and PUR tread, 70 kg

Caster in a fixed bracket with PUR tread and PP hub

This is a caster in a fixed bracket with a running surface in PUR and a hub in PP, built for straight transport where you want controlled travel without the wheel turning sideways. The tread is a cast polyurethane with a hardness of 98 degrees Shore A, a fairly firm surface. The fixed bracket holds the wheel in the direction of travel, which makes it easy to push a cart straight ahead or guide it along a set path.

The polyurethane gives a good balance between wear strength and care for the floor. It is firmer than a soft rubber, so it gets rolling with little force and keeps rolling resistance down on an even floor. At the same time PUR is softer than hard plastic and is gentler on painted concrete and tile than a wheel in plain nylon. The material takes wear well and stands up to most of the oils and greases found in a workshop.

A little about starting and rolling resistance. A firmer polyurethane like this one barely flattens under load, so the wheel gets going easily and rolls with little resistance once it is moving. Compared with a soft elastic wheel you get less cushioning but clearly lower rolling resistance; compared with a hard plastic wheel you get more care for the floor and less noise. That places PUR in between, which suits light carts that roll a lot.

The PP hub makes the wheel light and corrosion-free. The plastic is unaffected by moisture or mild chemicals and holds its shape at normal indoor temperature. Inside the hub sits a plain bearing that is simple and maintenance-free; it takes dust and splashes and needs no lubrication. A plain bearing gives slightly higher rolling resistance than a ball bearing, but with these lighter loads you barely notice it and the construction ends up tough against dirt.

The wheels come in diameters from 50 to 100 mm and carry up to 55 kg per wheel. A larger diameter rolls more easily over joints and small thresholds and lowers rolling resistance, while a smaller one keeps the overall height down where it is tight under a machine or a table. The bracket is mounted with a top plate, a square mounting plate with four screw holes, which gives a stable fastening against a flat underframe.

Where does it fit? A fixed caster in PUR with a PP hub often sits under lighter transport carts, shelf carts, appliance racks and assembly tables that have to roll straight and be steered by a separate swivel caster at the other end. It works well in workshop, warehouse, assembly and in rooms with ground or painted floors. The straight running makes it easy to keep a cart on track along a work line.

Think about the operating environment. Polyurethane and PP are happy in dry to slightly damp indoor environments and at normal room temperature. The fixed caster is not intended for swiveling, so combine it with a swivel caster when the cart has to be maneuvered in tight spaces. If the wheel stands still for a long time under full load, the tread can pick up a small flat spot, but it rolls out after a while and is normal for polyurethane.

Are you unsure which diameter suits your cart or how best to combine fixed casters with swivel casters? Get in touch and we will go through the load and the floor together.