At 40x80x18 mm and a unit weight of 0.367 kg, the installation envelope is fixed; further technical details are held in the specification table. This variant features increased radial clearance (C3). The open form and increased clearance (C3) meet where the lubricant is routed through the bearing and the position runs warm while doing so.
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.
ManufacturerFAG
Bearing typeDeep-groove ball bearings
Bore d40 mm
Outer Ø D80 mm
Width B18 mm
Dyn. load C31.5 kN(Catalogue value, not verified)
Stat. load C₀17.8 kN(Catalogue value, not verified)
Limiting speed13,600 min⁻¹(Catalogue value, not verified)
Reference speed10,500 min⁻¹(Catalogue value, not verified)
Weight0.367 kg
Sealsnone (open bearing)
Clearanceradial internal clearance greater than normal
Cagepressed steel cage
Materialstandard bearing steel
Tolerancetolerance class P0/PN (ABEC 1)
Bore typecylindrical bore
€6.72/ pc€9.81−31 %
incl. VAT, plus shipping · price drops with quantity
Lowest price in the 30 days before the reduction: €9.81
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QtyUnit priceDisc.
1 – 4€6.72—
5 – 9€6.53−3 %
10 – 24€6.39−5 %
25 – 49€6.19−8 %
50 – 99€6.06−10 %
4 more for −3% volume discount
From 100 pcs: price and lead time on request – subject to review.
Total (1 pc)€6.72
FAG 6208-C-C3 (-C3) Kugellager (40x80x18)
— 40 x 80 x 18 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.
