The dynamic load rating of 42.3 kN characterises this bearing. The static load rating is 24 kN. The limiting speed is 11000 rpm. This variant features increased radial clearance (C3). Too little and too much residual clearance produce different kinds of damage: the one preloading and additional heat in the rolling contact, the other a narrow load zone with few balls carrying at the same time.
Two losses lie between the clearance as delivered and the clearance in service, and they add up. The interference fit on the shaft expands the inner ring and takes a first share; the sustained temperature difference between the warmer inner ring and the cooler outer ring, coupled to the housing, takes a second. Increased clearance (C3) compensates for exactly these two shares so that a residual clearance within the intended range establishes itself once the arrangement has warmed up — it is a calculated quantity of the bearing position, not a property that would be selected on its own.
The residual clearance acts directly on load distribution: the wider it is, the smaller the circumferential sector in which balls carry and the higher the load on the individual ball; the tighter it is, the sooner the rolling contact is preloaded and generates additional heat, which closes the clearance further. Because this bearing is supplied in the open form, the lubricant carries the frictional heat directly out of the rolling chamber; oil and circulating lubrication are possible, and the temperature difference between the rings therefore develops differently than in a grease-filled, closed version.
Through-hardened standard bearing steel continues to define the temperature and load frame within which the ratings listed in the catalogue apply. At low radial load the wider clearance has to be taken into account: the unloaded part of the ball set is guided only by the cage and, without sufficient minimum load, it can slide instead of rolling.
Whether increased clearance (C3) is the right choice for a specific position therefore follows from the fit, the temperature gradient and the actual load taken together — not from any one of the three on its own.
ManufacturerSKF
Bearing typeDeep-groove ball bearings
Bore d40 mm
Outer Ø D90 mm
Width B23 mm
Dyn. load C42.3 kN
Stat. load C₀24 kN
Limiting speed11,000 min⁻¹
Reference speed17,000 min⁻¹
Weight0.591 kg
Sealsnone (open bearing)
Clearanceradial internal clearance greater than normal
Cagepolyamide cage
Materialstandard bearing steel
Tolerancetolerance class P0/PN (ABEC 1)
Bore typecylindrical bore
€28.32/ pc€38.57−27 %
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Lowest price in the 30 days before the reduction: €38.57
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QtyUnit priceDisc.
1 – 4€28.32—
5 – 9€27.48−3 %
10 – 24€26.91−5 %
25 – 49€26.06−8 %
50 – 99€25.49−10 %
4 more for −3% volume discount
From 100 pcs: price and lead time on request – subject to review.
Total (1 pc)€28.32
SKF 6308 TN9/C3 Kugellager (40x90x23)
— 40 x 90 x 23 mm
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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.
