SKF NNU 4956 B/SPC3W33 cylindrical roller bearing
- Brand
- SKF
- Category
- Bearings
- Subcategory
- Cylindrical roller bearings
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Decoding SKF NNU 4956 B/SPC3W33
- NNU 49Series
- Cylindrical roller bearings, NNU 49 series. Series differ in outside diameter and width even when the bore is the same.
- 56Bore
- Bore 280 mm (56 × 5).
- B/SPC3W33Suffix
- SKF suffix: identifies the variant, such as seals or shields, cage, internal clearance or other features.
NNU 4956 is the standard ISO basic designation, which sets the bearing type, series and bore.
Description
SKF NNU 4956 B/SPC3W33 belongs to cylindrical roller bearing, part of our Bearings range. Tell us how many you need by WhatsApp or email and we'll get back to you promptly with a quote for NNU 4956 B/SPC3W33 and any equivalents.
Double row cylindrical roller bearings in the SKF NNU range are built for machinery where radial forces are heavy and speeds stay high. The bronze cage and the two-row layout suit tough duty in production equipment. MR Industrial Accessories LLC supplies this line to maintenance and purchasing teams in the United States and Latin America.
Reading the code tells you what you are holding. NNU means a double row bearing whose inner ring carries no flanges while the outer ring does. A B in the designation points to a machined bronze cage. SPC marks special precision tolerance, and W33 means the outer ring has a lubrication groove plus holes. So NNU 4930 B/SPC3W33 packs all of that into a 150 mm bore unit, and NNU 4932 B/SPC3W33 and NNU 4956 B/SPC3W33 step up to bigger sizes. Decoding the string makes replacement straightforward.
Where do these bearings earn their place? Gearboxes, machine tool spindles, rolling mills, industrial pumps and mining equipment all call for high radial capacity and stiffness. Cement, paper, metallurgical and heavy machinery plants rely on them for the same reason. The two rows also let the bearing take combined loads and moments, though radial load remains its primary job.
Selection starts with the radial load, the running speed and the environment around the shaft. Fit matters: alignment has to be precise, and lubrication - grease or oil, depending on the case - has to be right. The W33 groove and holes make relubrication possible while the bearing stays in place. Check internal clearance before mounting and use the correct tools so rollers and raceways are not marked during installation.
Interchange is possible with bearings from other makers that share the same dimensional and design designation. Tolerances and cage style can differ from one manufacturer to another, so confirm the specifications and make sure the replacement meets the load and speed demands of your equipment. Send the complete part number by WhatsApp or email and our team will quote it and suggest equivalents where needed.
Dimensions
- Bore
- 280mm
Frequently asked questions
- What does the W33 suffix mean in an NNU bearing?
- It means the outer ring is fitted with a lubrication groove and three lubrication holes, so the bearing can be relubricated without being dismounted.
- How does an NNU bearing differ from an NU bearing?
- The NNU has two rows of rollers and an inner ring without flanges; the NU is single row with a flangeless inner ring. The NNU handles higher radial loads.
- How do I pick the right NNU bearing for my machine?
- Look at radial load, speed, space available and lubrication conditions. Check your equipment manual, or send us the current part number and we will advise.