This Resource Centre provides general guidance only. Always follow the equipment manufacturer’s instructions, the product technical data sheet and your site’s safe system of work. Isolate stored energy before maintenance. For safety-critical, regulated or uncertain applications, ask a competent engineer or the product manufacturer to confirm the specification.
The quickest route to a replacement is usually the designation marked on the bearing ring or seal. If the marking is missing or unreadable, accurate dimensions and construction details can normally narrow the search.
1. Record every visible marking
Clean only enough of the outer ring, inner ring or seal to reveal the code. Copy the complete designation, including spaces, slashes and suffixes. A suffix may describe a seal, shield, internal clearance, cage, accuracy class or other feature, so it can be just as important as the basic number.
Do not assume that two bearings with the same main number are identical. Their suffixes may indicate different operating characteristics.
2. Measure the three main dimensions
Use a vernier calliper or micrometer to measure:
- Inside diameter (d): the bore that fits over the shaft.
- Outside diameter (D): the diameter that fits into the housing.
- Width (B): the overall width of the bearing.
Measure in millimetres and check at more than one point if the bearing is worn or damaged. For tapered roller bearings, record the markings on both the cone and cup because they may be supplied as a matched set.
3. Identify the bearing construction
Look at the shape and arrangement of the rolling elements:
- Deep-groove ball bearing: versatile and commonly used for radial load with some axial load in either direction.
- Angular-contact ball bearing: designed for combined load and usually installed with a defined orientation or as a pair.
- Self-aligning ball bearing: accommodates a degree of angular misalignment.
- Cylindrical roller bearing: offers high radial load capacity; some designs allow axial displacement.
- Spherical roller bearing: suited to heavy radial load, some axial load and misalignment.
- Tapered roller bearing: carries combined radial and axial load and normally requires correct adjustment.
- Needle roller bearing: high radial capacity in a small radial space.
- Thrust bearing: primarily designed for axial load.
4. Check seals, shields and special features
A metal shield, contact seal and non-contact seal behave differently. Record whether the closure appears on one side or both sides. Also note snap-ring grooves, flanges, extended inner rings, tapered bores, eccentric locking collars or adapter sleeves.
5. Confirm the application
Before ordering, note:
- shaft and housing dimensions;
- radial and axial load;
- operating speed;
- normal and maximum temperature;
- exposure to water, dust or chemicals;
- lubrication method;
- required internal clearance;
- any need for electrical insulation, corrosion resistance or food-grade compliance.
If the old bearing failed prematurely, replacing it like for like without identifying the cause may repeat the failure.
What to send us
Send clear photographs of both faces, all markings and the application, together with the inside diameter, outside diameter and width. Include the machine make and model where available.
Need help sourcing the item?
Send the manufacturer, reference, photographs and operating details.