Support Roller Bearings

What is a support roller bearing?

A support roller bearing, also called a yoke type track roller, is a ready-to-fit roller bearing with a thick outer ring, designed to roll on a track, cam, or guide rail while supported on a pin or shaft. Unlike a stud type cam follower, a support roller has a bore instead of a stud, so it fits onto a pin that is supported on both sides, like a wheel in a fork. This gives it a higher load capacity and makes it well suited to heavy-duty machinery.

A standard support roller has four main parts:

• A thick-walled outer ring, which rolls on the track
• An inner ring with a bore, which fits onto the pin or shaft
• Needle rollers, cylindrical rollers, or balls between the inner and outer rings
• Washers, ribs, or seals that guide the outer ring and keep dirt out.

The outer ring is designed to take the load directly from the track.

• It is thick and hardened, so it can carry heavy radial loads and shocks without deforming.
• Most support rollers have a crowned outer ring, which reduces edge loading if the roller is tilted against the track. Cylindrical outer rings are also available for accurate tracks.

Outer rings, inner rings, and rolling elements are made from hardened bearing steel. Most support rollers are supplied greased and sealed, ready to fit.

Why are support roller bearings essential?

They give machines a strong, simple way to guide or carry a moving part on a track. Because the pin is supported on both sides, the load is shared between two supports instead of one, so a support roller carries more load than a stud type cam follower of the same size. The thick outer ring takes heavy radial loads and shocks directly from the track, while the bearing inside lets it roll with low friction.

They come in standardised sizes, with or without an inner ring, sealed or open, and with needle, cylindrical roller, or ball bearing designs. This makes it easy to choose the right balance of load capacity, speed, and space for each application.

Typical applications include:

• Conveyors and roller tracks
• Forklift masts and lifting equipment
• Cranes and hoists
• Steel and metal processing lines
• Packaging and bottling machines
• Printing machines
• Linear guides and slides
• Cam mechanisms and indexing drives
• Agricultural and construction machinery
• Sliding doors and gates

The main types of support roller bearings

• Support rollers with axial guidance, caged needle rollers (NATR) - These have washers that guide the outer ring axially and a cage that holds the needles. They run with low friction and suit moderate loads and higher speeds.
• Support rollers with axial guidance, full complement needle rollers (NATV) - These have no cage, so more needles can be fitted, giving higher load capacity for slow or shock-loaded applications.
• Support rollers with full complement cylindrical rollers (NUTR) - These have cylindrical rollers instead of needles and carry very high radial loads, with some ability to take axial loads. The rollers themselves guide the outer ring.
• Heavy-duty support rollers with a central rib (PWTR, NNTR) - These have two rows of full complement cylindrical rollers separated by a central rib, which guides the outer ring. They are designed for the heaviest loads.
• Support rollers without axial guidance (STO) - These have an inner ring but no guide washers, so the surrounding parts must provide axial guidance. They are not self-retaining, so the parts can be fitted separately.
• Support rollers without an inner ring (RSTO, RNA22) - These run directly on a hardened and ground pin or shaft, which saves space and allows a larger pin diameter.
• Ball bearing support rollers (LR) - These have a thick outer ring on a ball bearing, which suits higher speeds and lighter loads, with some ability to take axial loads.

How to choose the right support roller bearing?

• Size and dimensions - Choose the outer diameter to suit the track and space available, and the bore to suit the pin. Check the width fits between the supports.
• Load - Work out the radial load and any shocks. Compare it with the bearing’s basic dynamic load rating and basic static load rating, and with the permissible load on the outer ring, which are published in manufacturers’ catalogues.
• Rolling elements - Caged needle rollers suit moderate loads and higher speeds. Full complement needles or cylindrical rollers suit heavy loads and lower speeds. Ball bearing types suit higher speeds and lighter loads.
• Axial guidance - Choose a type with axial guidance if the outer ring must be located by the bearing itself. Choose a type without axial guidance if the surrounding parts provide it.
• Inner ring - Choose a type without an inner ring if the pin is hardened and ground and space is tight. Otherwise, choose a type with an inner ring.
• Outer ring profile - Use a crowned outer ring where alignment between the roller and track cannot be guaranteed. Use a cylindrical outer ring where alignment is accurate.
• Track and environment - The track must be hard and smooth enough for the load. Use sealed types for dirt and moisture.

Essential references and specialised ranges

How the numbering works:

The letters at the start identify the type:

NATR = with axial guidance, caged needle rollers

NATV = with axial guidance, full complement needle rollers

NUTR = full complement cylindrical rollers

PWTR, NNTR = double-row full complement cylindrical rollers with a central rib

STO = without axial guidance, with inner ring

RSTO = without axial guidance or inner ring

LR = ball bearing support roller

For most types, the number after the letters relates to the bore in mm, so an NATR 20 fits a 20mm pin. On cylindrical roller types such as NUTR, the number gives the bore and outer diameter, so an NUTR 2052 has a 20mm bore and 52mm outer diameter.

Numbering varies between types and manufacturers, so always check the bore, outer diameter, and width before ordering a replacement.

Suffixes:

PP = sealed version with an optimised crowned outer ring profile

X = cylindrical (flat) outer ring instead of crowned

2RS, 2RSR = contact seals on both sides

XL = X-life design with higher load capacity

Suffix codes vary between manufacturers, so check the supplier’s catalogue for the exact meaning.

FAQ - All you need to know about support roller bearings

What is the difference between a support roller and a cam follower?

A cam follower usually has a built-in threaded stud, so it bolts straight into a frame and is held from one side. A support roller has a bore and fits onto a pin supported on both sides. Because the pin is supported at both ends, support rollers carry higher loads.

Do I need a support roller with or without an inner ring?

Use a support roller without an inner ring only if the pin is hardened and ground to act as a raceway. If the pin is not hardened, choose a support roller with an inner ring.

What does axial guidance mean?

Axial guidance means the bearing itself stops the outer ring moving sideways, using washers or ribs. Support rollers without axial guidance rely on the surrounding parts, such as the yoke or side plates, to keep the outer ring in place.

Do support roller bearings need lubrication?

Yes. They are supplied greased, but many applications need regular regreasing, especially with heavy loads, shocks, or dirt. Grease is usually fed through a lubrication hole in the pin and inner ring. Sealed types hold their grease better and need less frequent relubrication.

Click here to learn how to maintain a bearing.

Can I replace a support roller myself?

In most cases, yes. Remove the pin, slide the old roller out of the yoke, and fit the new one. Make sure the inner ring is clamped or located axially as the design requires, and that the yoke faces support the inner ring evenly. Never hammer on the outer ring.

How do I identify a support roller I need to replace?

The reference is usually marked on the side face of the outer or inner ring. If the markings are worn away, measure the outer diameter, bore, and width with callipers. Also note whether there is an inner ring, whether the outer ring is crowned or flat, and whether the roller is sealed.

Click here to learn how to measure a bearing.

How can I tell if a support roller is worn or failing?

Warning signs include:

• Flat spots, pitting, or flaking on the outer ring
• The roller sliding instead of rolling along the track
• Rough or uneven rotation when turned by hand
• Play between the outer ring and the inner ring or pin
• Noise or vibration as the roller passes along the track
• Grease leaking from the seals
• Wear marks or grooves forming on the track

Click here to learn how to recognise a failing bearing and tips on how to extend the life of bearings.