The SKF 6303-2Z/C3 is a single row deep groove ball bearing with a 17 mm bore, 47 mm outside diameter and 14 mm width, fitted with a non-contact metal shield on both sides (2Z) and C3 radial internal clearance. It belongs to the SKF Explorer performance class and, per SKF, carries a basic dynamic load rating of 14.3 kN and a basic static load rating of 6.55 kN.
The designation can be read directly: 6 = single row deep groove ball bearing, 3 = ISO dimension series 03 (medium), a heavier cross-section with larger balls for higher loads on the same shaft size; 03 = bore code for 17 mm; 2Z = shields on both sides; C3 = radial internal clearance greater than normal.
Shields leave a narrow gap to the inner ring, so friction stays low and SKF lists a limiting speed of 17,000 r/min for this version, compared with 11,000 r/min for the sealed 6303-2RSH/C3. That makes the 2Z design the usual choice for electric motors, fans and other clean, fast-running positions.
Technical data
| SKF designation | 6303-2Z/C3 |
|---|---|
| Bearing type | Single row deep groove ball bearing |
| Dimension series | 63 – ISO dimension series 03 (medium) |
| Bore diameter (d) | 17 mm |
| Outside diameter (D) | 47 mm |
| Width (B) | 14 مم |
| Basic dynamic load rating (C) | 14.3 kN |
| Basic static load rating (C0) | 6.55 kN |
| Reference speed | 34,000 r/min |
| Limiting speed | 17,000 r/min |
| SKF performance class | SKF Explorer |
| Sealing | Shield on both sides (non-contact) |
| Radial internal clearance | C3 (greater than normal) |
| Cage | Sheet metal (pressed steel) |
| Bore type | Cylindrical |
| Lubricant | Grease, no relubrication feature |
| Material | Bearing steel |
| Net weight | 0.112 kg |
| Condition | New, original SKF |
Typical applications
- Small motors, power tools and household appliances
- Compressors and vacuum pumps
- Electric motors and generators (drive-end and non-drive-end positions)
- Machine-tool and woodworking spindles running at moderate speed
- Like-for-like replacement of a worn SKF 6303-2Z/C3
Compatibility and replacement
Every 6303 bearing made to ISO 15 has the same 17 x 47 x 14 mm boundary dimensions, so this bearing fits wherever a 6303 with shields and C3 clearance from another maker was used. Suffixes differ between brands: shields are often marked ZZ or 2Z, contact seals 2RS, 2RS1, DDU or LLU, and the clearance C3 may appear as “C3” or “/C3”. Always match the sealing arrangement and the clearance class shown on the old bearing; if your machine needs the other closure, the 6303-2RSH/C3 is the same size.
Frequently asked questions
What is the difference between 6303-2Z/C3 and 6303-2RSH/C3?
Only the closures. The 6303-2Z has non-contact steel shields; the 2RSH version has contact rubber seals. Per SKF, the limiting speed is 17,000 r/min for 2Z and 11,000 r/min for 2RSH; the load ratings are the same. Choose shields for speed and low friction, seals for dirt and moisture.
What does C3 mean, and can I use a bearing without it?
C3 is a radial internal clearance greater than normal. It leaves room for the inner ring to expand with a tight shaft fit or with heat, which is why electric motors and hot-running machines often specify it. Fit the clearance class the machine maker specifies or that is marked on the old bearing; do not swap C3 for normal clearance without checking.
What do the load ratings mean in practice?
The basic dynamic load rating C (14.3 kN) is used to calculate rating life: under ISO 281, a ball bearing loaded at one tenth of C has a basic rating life of 1,000 million revolutions. The static rating C0 (6.55 kN) is the reference for heavy loads at very low speed or standstill.
Related parts
- SKF 6303-2RSH/C3 (sealed version)
- SKF 6302-2Z/C3 (15 mm bore)
- SKF 6304-2Z/C3 (20 mm bore)
- All SKF 6300 Series Bearings
Part of the SKF 6300 series stocked by RendatSP for electric motors, gearboxes, pumps, fans, conveyors and general industrial machinery, with fast shipping to Iraq, Saudi Arabia, UAE, Egypt, Yemen, Libya and across the Middle East and Africa.
Every part RendatSP supplies is new and original, carries a 1-year warranty and ships worldwide by air in 5 to 7 days once ready (shipping, payment and warranty). Send us the part number and quantity on WhatsApp or through the inquiry form and we will quote the same working day. Agents in Saudi Arabia, Iraq, the UAE, Egypt, Oman, Libya, Morocco, Mauritania, Yemen, Algeria and Jordan.
