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Bower779/774D/X1STwo-Row TDO Tapered Roller Bearing Set, 4 Pieces – 3.875 in Bore, 7.125 in OD, 4.125 in Overall Width, Double Cup with Cone Spacer

Condition: New – Open box
Condition Note: Made In USA, (2) 779 (1) 774-D (1) X1S-779, New Old Stock

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1 in stock

Two-row TDO tapered roller bearing set, 3.875 x 7.125 x 4.125 in. One double cup, two cones and a cone spacer, four pieces, factory-set.

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$390.12

1 in stock

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Specifications

Key Specifications

MFR / BrandBower
MPN779/774D/X1S
Model779 / 774D / X1S-779
Bearing TypeTapered Roller Bearing Cone
ID3.875 in (98.425 mm)
OD7.125 in (180.975 mm)
Width4.125 in (104.775 mm)

Technical Specifications

MaterialSteel
ConditionNew – Open box
Base Number779/774D
Industry TermsTDO bearing; tapered double outer; double cup tapered roller bearing; two-row taper bearing set; cone spacer set; matched taper assembly; Bower double cup taper
Total Width4.125 in (104.775 mm) overall; cone inner ring width B 1.875 in each row
Condition NoteMade In USA, (2) 779 (1) 774-D (1) X1S-779, New Old Stock
Bore Shaft Size3.875 in (98.425 mm)
Mpn Variants779/774D/X1S; 779-774D-X1S; 779 774D X1S; 779/774D; 779-774-D; 774-D; 774D; X1S-779; X1S779; 779
Compatible With ReplacesPiece list: 2 x cone 779, 1 x double cup 774-D, 1 x cone spacer X1S-779. Timken catalogue designation for the two-row assembly: 779/774D.
Arrangement ConfigurationTDO (Tapered Double Outer) - two cones back to back in one double cup, separated by a ground cone spacer
Precision ClassNot specified
Series774
Cage MaterialSteel
Number Of Rows2
Bore TypeStraight
Harmonization Code8482.20.00
Design UnitsInch
Bearing MaterialSteel
Part Number779/774D/X1S-779
Cage TypeStamped

Cross-References

Cross Reference 1Timken 779/774D (same two-row TDO assembly, Timken catalogue designation)
Cross Reference 2Timken 779 (cone component of this set)
Cross Reference 3Timken 774-D (double cup component of this set)
Cross Reference 4Timken X1S-779 (cone spacer component of this set)
Cross Reference 6Timken 779/772 (related size, single cup, one row, 1.875 in width)
Cross Reference 7Timken 777/774D, 778/774D, 782/774D, 783/774D (related sizes, same double cup, different bore)
Seller Part Number: BI4#JRINGY

Product Description

What this part is

Bower 779/774D/X1S is a two-row inch-series tapered roller bearing set in the TDO configuration — Tapered Double Outer. Bore: 3.875 in (98.425 mm). Outside diameter: 7.125 in (180.975 mm). Overall assembly width: 4.125 in (104.775 mm). Cone inner ring width (B), each row: 1.875 in (47.625 mm). Series: 774.

Decoding the designation

779 is the cone. 774-D is the double cup: the D on a cup designates a one-piece double outer ring with two raceways, and it takes two cones. X1S-779 is the cone spacer, which sets the axial distance between the two cones and therefore fixes the internal setting of the pair. Design units: inch.

Quantity and configuration

Four pieces in one set: two 779 cones, one 774-D double cup, and one X1S-779 cone spacer. Two rows. Rolling elements: tapered rollers. Cage: stamped steel. Bearing material: steel. Open, unsealed.

What these specs mean in practice

A TDO carries thrust in both directions and takes overturning moment, because the two rows sit back to back with their effective load lines diverging outward. That wide effective spread gives a TDO high moment stiffness in a short axial envelope, which is why the type is used in wheel hubs, sheave blocks, crane travel wheels and idler positions where one bearing has to locate the shaft completely. The X1S-779 spacer is ground to length, so the set arrives with its internal clearance or preload already established rather than being set on assembly.

Fitting notes

The double cup mounts in a single straight housing bore and locates against one housing shoulder. Each 779 cone presses onto the shaft with the spacer between their backfaces. Lubrication: oil or grease. The set is matched: the two cones, the double cup and the spacer are ground as a unit and are kept together.

Interchange guidance

Searchable forms of the designation: 779/774D/X1S, 779-774D-X1S, 779 774D X1S, 774-D, 774D, X1S-779, X1S779, 779. Bower is a legacy tapered roller brand now within Timken, and the Timken catalogue designation for this two-row assembly is 779/774D. Related sizes on the same 774-D double cup and the same 7.125 in outside diameter take different cones: 777/774D at 3.75 in bore, 778/774D at 3.625 in bore, 782/774D at 4.125 in bore and 783/774D at 3.937 in bore. The 779/772 is a related size using a single cup, giving one row at 1.875 in width rather than two rows at 4.125 in.

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