The SKF 6304-2RSH/C3 is a single row deep groove ball bearing with a 20 mm bore, 52 mm outside diameter and 15 mm width, fitted with a contact rubber seal on both sides (2RSH) and C3 radial internal clearance. It belongs to the SKF Explorer performance class and, per SKF, carries a basic dynamic load rating of 16.8 kN and a basic static load rating of 7.8 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; 04 = bore code for 20 mm (04 x 5); 2RSH = contact seals on both sides; C3 = radial internal clearance greater than normal.
The contact seals rub lightly on the inner ring, which keeps grease in and dust, water and washdown spray out better than a shield. The price of that protection is speed: SKF lists a limiting speed of 9,500 r/min for this sealed version, against 15,000 r/min for the shielded 6304-2Z/C3.
Technical data
| SKF designation | 6304-2RSH/C3 |
|---|---|
| Bearing type | Single row deep groove ball bearing |
| Dimension series | 63 – ISO dimension series 03 (medium) |
| Bore diameter (d) | 20 mm |
| Outside diameter (D) | 52 mm |
| Width (B) | 15 mm |
| Basic dynamic load rating (C) | 16.8 kN |
| Basic static load rating (C0) | 7.8 kN |
| Reference speed | 30,000 r/min |
| Limiting speed | 9,500 r/min |
| SKF performance class | SKF Explorer |
| Sealing | Seal on both sides (low-friction) |
| 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 | 0.144 kg |
| Condition | New, original SKF |
Typical applications
- Industrial gearboxes and drive trains
- Belt and roller conveyors exposed to dust
- Pumps and mixers in damp or dusty plant rooms
- Idlers, pulleys and tensioners
- Like-for-like replacement of a worn SKF 6304-2RSH/C3
Compatibility and replacement
Every 6304 bearing made to ISO 15 has the same 20 x 52 x 15 mm boundary dimensions, so this bearing fits wherever a 6304 with contact seals 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 6304-2Z/C3 is the same size.
Frequently asked questions
What is the difference between 6304-2RSH/C3 and 6304-2Z/C3?
Only the closures. The 6304-2Z has non-contact steel shields; the 2RSH version has contact rubber seals. Per SKF, the limiting speed is 15,000 r/min for 2Z and 9,500 r/min for 2RSH; the load ratings are the same. Choose shields for speed and low friction, seals for dirt and moisture.
What do the load ratings mean in practice?
The basic dynamic load rating C (16.8 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 (7.8 kN) is the reference for heavy loads at very low speed or standstill.
Is it the same as a 6304ZZ or 6304-2RS from another brand?
Dimensionally yes: all 6304 bearings share 20 x 52 x 15 mm under ISO 15. A ZZ marking corresponds to the 2Z shielded design and 2RS to this sealed design; load ratings and speeds differ between makers, and the figures on this page are the SKF values.
Related parts
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.
