Model datasheet
NA4903 Needle Roller Bearing 17×30×13mm
Confirm the model number, dimensions, suffix, and replacement notes before sending a quotation request for repair or MRO sourcing.
Verified directory reference: Specifications have been reviewed, but the complete suffix and current order requirement must still be confirmed before purchase.
NA4903 bearing specifications
| Parameter | Value |
|---|---|
| Model | NA4903 |
| Category | Needle Roller Bearing |
| Series | NA4900 Series |
| Inner Diameter (ID) | 17 mm |
| Outer Diameter (OD) | 30 mm |
| Width | 13 mm |
| Material | Chrome Steel GCr15 |
| Closure | Open |
| Dynamic Load | 9.95 kN |
| Static Load | 10.6 kN |
| Speed Limit | 18000 RPM |
| Precision | P0 (ABEC-1) |
| Clearance | CN (Standard) |
NA4903 brand designation references
Interchange Numbers: NA4903
Catalogue designations reviewed for this model include SKF NA 4903, FAG NA4903, NSK NA4903, NTN NA4903.
These catalogue references have source records, but the complete suffix and operating requirement must still be confirmed.
| Brand | Brand designation | Reference status |
|---|---|---|
| SKF | NA 4903 | Source recorded SKF rolling bearing catalogue — NA 4903 · |
| FAG | NA4903 | Source recorded Schaeffler FAG rolling bearing catalogue — NA4903 · |
| NSK | NA4903 | Source recorded NSK rolling bearing catalogue — NA4903 · |
| NTN | NA4903 | Source recorded NTN rolling bearing catalogue — NA4903 · |
Frequently asked questions about NA4903
What does the open design mean on a NA4903 bearing?
The NA4903 (17mm x 30mm x 13mm) is supplied open — without seals or shields — so lubrication and relubrication come from the surrounding housing or an external system. Compare seal types before deciding on the replacement.
Which part numbers are equivalent to NA4903?
Equivalent designations include NA 4903 . These are brand-specific numbers for the same ISO boundary dimensions as the NA4903 (17mm x 30mm x 13mm). The basic number matching does not confirm the complete specification — compare seal type, clearance, precision, cage, and lubrication suffix before ordering.
Does the NA4903 come with C3 clearance?
This directory lists the NA4903 with CN (Standard). C3 (increased internal clearance) versions are common for higher operating temperatures, higher speeds, or press-fit arrangements — specify the required clearance on your RFQ so the quotation matches the application. Read the clearance guide.
The NA4903 is listed as a 17×30×13mm needle roller bearing in open configuration. Part of the NA4900 series — a compact single-row needle roller bearing family from 10 to 50 mm bore. The directory records chrome steel gcr15 and P0 (ABEC-1) precision grade for RFQ verification.
The NA4903 bearing cross-references to SKF NA 4903, FAG NA4903, NSK NA4903 and NTN NA4903. This means you can replace an SKF equivalent, FAG alternative, NSK cross reference, or NTN interchange part with the same ISO boundary dimensions. Compare the full specification table and designation suffixes before ordering, especially the closure (open vs sealed) and internal clearance (C3 vs CN).
About the NA4900 Series
The NA4900 series is a needle roller bearing with a machined outer ring and a full complement of needle rollers guided by the inner ring. The thin cross-section delivers high radial load capacity for its diameter, which makes the series a common choice where space is limited and radial loads are high.
Common Applications
- Gearboxes
- Automotive
- Compressors
- Pumps
Factory-Direct Supply from China
The NA4903 is available factory-direct from KIHOI, a bearing supplier and manufacturer in China. Quotations confirm the model, suffix, quantity, packing basis, and shipment terms — with low minimum order quantities for MRO and distribution buyers. Send the complete part number and destination country to request a China factory-direct quotation.
Common applications for NA4903
The NA4903 is a common replacement candidate in the following equipment. Open the application guide to confirm the checks that apply to your machine before ordering:
Compare NA4903 with nearby sizes
These models are the closest sizes in the same bearing family. They are not interchangeable — confirm the bore, outside diameter, and width before replacing the existing part.
| Model | Dimensions | Closure | Action |
|---|---|---|---|
| NA4901 | 12mm x 24mm x 13mm | Open | View specifications |
| NA4902 | 15mm x 28mm x 13mm | Open | View specifications |
| NA4904 | 20mm x 37mm x 17mm | Open | View specifications |
| NA4905 | 25mm x 42mm x 17mm | Open | View specifications |
| NA4906 | 30mm x 47mm x 17mm | Open | View specifications |
Fast bearing RFQ
Tell us what bearing you need.
A model number is enough to start. If the marking is unclear, send the dimensions, application, or a shared photo link in the message.
- Small repair quantities and mixed model lists
- Model, suffix, and replacement review
- Price, lead time, packing, and shipping details