634-2RS bearing
The 634-2RS is a miniature ball bearing with a 4 mm bore, 16 mm outside diameter and 5 mm width, rubber sealed on both sides.
Size & specs
| Type | Miniature ball bearing |
|---|---|
| Bore (ID) | 4 mm (0.157 in) |
| Outside diameter (OD) | 16 mm (0.63 in) |
| Width | 5 mm (0.197 in) |
| Seals / shields | 2RS: rubber sealed on both sides |
Cross reference: same bearing, other brands
| SKF | 634-2RSH |
|---|---|
| NTN | 634LLU |
| NSK | 634DDU |
| FAG | 634-2RSR |
| Timken | 634-2RS |
| Koyo | 634-2RS |
Budget brands usually sell this as 634-2RS. Add C3 if your old bearing was stamped C3 (looser fit for hot-running motors).
Where to buy
Other versions
Other bearings with a 4 mm bore
Questions
What size is a 634-2RS bearing?
4 × 16 × 5 mm (bore × outside diameter × width).
What does 2RS mean?
2RS means rubber seals on both sides. Seals keep out dirt and water better than metal shields, which makes them a good default for farm, outdoor and wet equipment.
Is 634-2RS the same as 634-2RSH or 634LLU?
Yes. They share the same size and seal type. Brands just use different suffixes: SKF uses 2RSH, NTN uses LLU, NSK uses DDU and FAG uses 2RSR.