At 25x62x17 mm and a unit weight of 0.24 kg, the installation envelope is fixed; further technical details are held in the specification table. This variant features increased radial clearance (C3). The shields do not touch the rings and therefore exert no influence on the clearance; what they change is the path by which heat leaves the bearing.
The combination of shields on both sides with increased clearance (C3) describes a position that is closed and nevertheless runs warm. Because no lubricant is routed through the rolling chamber, the frictional heat leaves the bearing through the inner and outer ring, and the ring with the better thermal connection — as a rule the outer ring in the housing — stays cooler than the inner ring on the shaft.
It is precisely this difference that consumes clearance: the warmer inner ring expands further and, together with the share the interference fit has already taken, the remaining clearance can fall below the intended range. Increased clearance (C3) holds an allowance ready for that, so that a residual clearance establishes itself in the warm running state at which the rolling contact is not preloaded.
The second effect of the same temperature concerns the lubricant: the grease charge is enclosed by the shields and dimensioned for the service life, so that its ageing at elevated temperature — rather than material fatigue — frequently becomes the limiting quantity. The operating temperature of the position is therefore to be checked against the data for the grease charge; where it lies above, a version with a different filling or a relubricatable solution is to be selected rather than adjusting the clearance class alone.
Since the shields do not touch the rings, they contribute neither a frictional torque nor a heat source of their own; the permissible speed follows from the cage and the lubricant. Through-hardened standard bearing steel sets the frame for hardness and dimensional accuracy within which this interplay holds.
ManufacturerNTN
Bearing typeDeep-groove ball bearings
Bore d25 mm
Outer Ø D62 mm
Width B17 mm
Dyn. load C23.5 kN(Catalogue value, not verified)
Stat. load C₀10.9 kN(Catalogue value, not verified)
Limiting speed14,000 min⁻¹(Catalogue value, not verified)
Reference speed12,000 min⁻¹(Catalogue value, not verified)
Weight0.24 kg
Sealsshields on both sides
Clearanceradial internal clearance greater than normal
Cagepressed steel cage
Materialstandard bearing steel
Tolerancetolerance class P0/PN (ABEC 1)
Bore typecylindrical bore
€6.85/ pc
incl. VAT, plus shipping · price drops with quantity
In stock
Typically ready to ship in 1–2 days
In stock · ships via DPD, UPS or Deutsche Post
QtyUnit priceDisc.
1 – 4€6.85—
5 – 9€6.65−3 %
10 – 24€6.52−5 %
25 – 49€6.31−8 %
50 – 99€6.17−10 %
4 more for −3% volume discount
From 100 pcs: price and lead time on request – subject to review.
Total (1 pc)€6.85
NTN 6305 ZZC3/5K Kugellager (25x62x17)
— 25 x 62 x 17 mm
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✓Free shipping over €100 · 14-day returns
✓Purchase on invoice – first order paid before dispatch, then 14-day terms for approved business customers
Same dimensions means the same bearing type and matching main dimensions (d × D × B). Sealing, cage, internal clearance and execution (e.g. material, precision, grease fill) are encoded in the suffix and may differ — please check before ordering. Equivalent additionally means the same sealing, internal clearance and tolerance class; the cage and other suffix features (e.g. lubrication groove) may differ.
