The SKF 6305-2Z/C3 is a single row deep groove ball bearing with a 25 mm bore, 62 mm outside diameter and 17 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 23.4 kN and a basic static load rating of 11.6 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; 05 = bore code for 25 mm (05 x 5); 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 13,000 r/min for this version, compared with 7,500 r/min for the sealed 6305-2RS1/C3. That makes the 2Z design the usual choice for electric motors, fans and other clean, fast-running positions.
Technical data
| SKF designation | 6305-2Z/C3 |
|---|---|
| Bearing type | Single row deep groove ball bearing |
| Dimension series | 63 – ISO dimension series 03 (medium) |
| Bore diameter (d) | 25 mm |
| Outside diameter (D) | 62 mm |
| Width (B) | 17 mm |
| Basic dynamic load rating (C) | 23.4 kN |
| Basic static load rating (C0) | 11.6 kN |
| Reference speed | 24,000 r/min |
| Limiting speed | 13,000 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 | 0.228 kg |
| Condition | New, original SKF |
Typical applications
- Industrial gearboxes and drive trains
- Gearbox input shafts and speed reducers
- Machine-tool and woodworking spindles running at moderate speed
- Compressors and vacuum pumps
- Like-for-like replacement of a worn SKF 6305-2Z/C3
Compatibility and replacement
Every 6305 bearing made to ISO 15 has the same 25 x 62 x 17 mm boundary dimensions, so this bearing fits wherever a 6305 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 6305-2RS1/C3 is the same size.
Frequently asked questions
What is the difference between 6305-2Z/C3 and 6305-2RS1/C3?
Only the closures. The 6305-2Z has non-contact steel shields; the 2RS1 version has contact rubber seals. Per SKF, the limiting speed is 13,000 r/min for 2Z and 7,500 r/min for 2RS1; the load ratings are the same. Choose shields for speed and low friction, seals for dirt and moisture.
Is it the same as a 6305ZZ or 6305-2RS from another brand?
Dimensionally yes: all 6305 bearings share 25 x 62 x 17 mm under ISO 15. A ZZ marking corresponds to this shielded design and 2RS to the sealed design; load ratings and speeds differ between makers, and the figures on this page are the SKF values.
What do the load ratings mean in practice?
The basic dynamic load rating C (23.4 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 (11.6 kN) is the reference for heavy loads at very low speed or standstill.
Related parts
- SKF 6305-2RS1/C3 (sealed version)
- SKF 6304-2Z/C3 (20 mm bore)
- SKF 6306-2Z/C3 (30 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.
