3878/20

Manufacturer-published tapered-roller dimensions, load ratings, fatigue load limit, and limiting speed.

Bore d36.512 mmOutside diameter D85.725 mmOverall width T30.162 mmDynamic rating Cr135 kNKoyo calculation tool ↗

Live manufacturer specification row

Published specifications

Inch family

Designation: 3878/20
Family: Inch Tapered Roller Bearings
Bore d: 36.512 mm
Outside diameter D: 85.725 mm
Overall width T: 30.162 mm
Inner ring width B: 30.162 mm
Minimum corner radius r: 0.8 mm
Minimum corner radius r1: 3.2 mm
Dynamic load rating Cr: 135 kN
Static load rating C0r: 136 kN
Fatigue load limit Cu: 20.3 kN
Grease limiting speed: 4,800 rpm
Published row text: 3878/20 | 36.512 | 85.725 | 30.162 | 30.162 | 0.8 | 3.2 | 135 | 136 | 20.3 | 4800

Verification boundary

Do not infer interchange

Exact set architectureConfirm metric versus inch family, cone/cup identity, series, and complete designation.

Fits and geometryVerify shaft/housing seats, shoulders, fillets, preload/endplay, and mounting arrangement.

DutyCheck combined radial/axial loading, lubrication, speed, temperature, contamination, and required life.

Current manufacturer dataUse the linked JTEKT/Koyo calculation and CAD tools before ordering.

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