NTNLM603049/LM603011Two-Row 2TS Matched Tapered Roller Bearing Assembly 1.7812″ Bore x 3.0625″ OD – Complete 6-Piece Pre-Set Assembly

Product Description

What this part is

This is a complete two-row (2TS) matched tapered roller bearing assembly built from LM603049 cone and LM603011 cup members, supplied under the assembly number LM603049-90033. It is one pre-configured assembly, factory-selected so that its members work together to produce a specific internal setting, and it is sold and shipped as one item.

Quantity and configuration

Unit Quantity: one assembly comprising six individual bearing pieces. Piece by piece, what is in the box:

2 x LM603049: standard cones, inner rings with tapered rollers and cages.

2 x LM603011: standard cups, outer races.

1 x LM603049XF: special-feature cone.

1 x LM603011EX: special-feature cup.

That is six pieces forming one two-row assembly with special-feature cone and cup members.

Decoding the designation

LM603049 is the cone, the inner ring plus roller and cage assembly. LM603011 is the cup, the outer race. Together LM603049/LM603011 is the standard single-row set designation. The trailing -90033 is an assembly number in the Timken-style convention adopted across the inch tapered roller bearing industry: a dash number in the 90000 range identifies a specific pre-configured matched assembly rather than a loose component. So LM603049-90033 means a defined, catalogued build, which is why the box contains six pieces and not two. A plain LM603049 or a plain LM603049/LM603011 is a bare cone or a single-row set, which is a different item.

On the special-feature suffixes: XF on the cone and EX on the cup denote members that differ from the base part in some controlled respect, typically a modified width, face or raceway feature. In an assembly like this one, those modified members are what set the internal spacing and therefore the endplay or preload of the finished two-row unit.

Published single-row dimensions

Bore d: 1.7812 in / 45.242 mm.

Cup outside diameter D: 3.0625 in / 77.788 mm.

Single-row assembly width T: 0.7812 in / 19.842 mm.

Cup width C: 0.5937 in.

Cone width B: 0.7812 in.

Weight: approximately 0.37 kg per single-row set.

These are the dimensions of one row. The overall width of the assembled two-row unit depends on the special-feature members and on whether a spacer is used.

Why a two-row taper assembly instead of two single-row bearings:
A single-row tapered roller bearing carries radial load and thrust in one direction only. It has to be opposed by a second bearing to handle thrust the other way, and even then the pair has to be set correctly at assembly. A two-row matched assembly does three things a single-row set cannot.

Thrust in both directions: the two rows oppose each other internally, so the unit takes axial load either way without needing a second bearing position to react it.

Moment (overturning) load resistance: because the two rows are axially separated inside one unit, they generate a couple that resists tilting of the shaft. A single-row taper is effectively a point support. This is why two-row assemblies show up in wheel ends, overhung pinions, spindle noses and anywhere a cantilevered load tries to cock the shaft.

Setting comes pre-established: the internal endplay or preload is determined by the assembly’s own members rather than by shims and a mechanic’s dial indicator, which removes the biggest source of variability in a taper installation.

2TS-DM versus 2TS-IM, direct and indirect mounting

Two-row taper assemblies are built in two orientations, and the difference determines how much moment load the unit can take.

2TS-DM (direct mount): the two cups are back to back. The effective load lines converge outside the bearing, which gives a narrower effective spread and therefore lower moment stiffness. This is the arrangement used when the assembly is essentially a compact radial-plus-thrust support.

2TS-IM (indirect mount): the two cones are back to back. The effective load lines diverge, giving a wider effective spread and substantially better resistance to overturning moments and to shaft misalignment under load.

Which orientation is required is set by the machine design: a housing built for a direct-mount unit locates a direct-mount unit.

Why the six pieces belong together

The XF cone and EX cup are the members that establish the internal spacing and therefore the setting of the assembly. The pieces were selected and finished as a group. Split across two separate single-row positions, neither position is at a known setting, and the special-feature members in particular produce an endplay with no published data to interpret it against.

Interchange guidance

Useful search and cross-reference forms for the members and the set:

LM603049 (cone), LM603011 (cup).

LM603049XF, LM603011EX (special-feature members).

LM603049-90033 (this assembly number), LM603049/LM603011, LM603049/11.

Metric envelope: 45.242 x 77.788 x 19.842 mm.

Timken LM603049/LM603011, SKF LM603049/11, Koyo LM603049R.

The LM603049/LM603011 basic numbers are industry-standard inch taper numbers produced to a common envelope by NTN, Timken, SKF, Koyo and others, so the single-row members cross cleanly. The assembly number LM603049-90033 is a specific build, and another manufacturer’s 90033 is a separately defined configuration. Match on the assembly number where you can, and confirm the piece content when you cannot.