oemntn.com

Gearbox shaft position guide · NTN authorized distributor

Select NTN Gearbox Bearings by Shaft Position, Not Just Size

oemntn.com is an NTN authorized distributor based in Hong Kong, supplying NTN cylindrical, tapered and spherical roller bearings for gearbox and reducer overhaul worldwide. Every quotation follows the shaft position, arrangement and NTN execution specified for the original equipment.

  • Input shaft
  • Intermediate shaft
  • Output shaft
  • Locating / non-locating
  • Paired arrangement
Send Your Shaft Position List → Browse Shaft Positions
Industrial reducer schematic showing input, intermediate and output shaft bearing positions
Reducer layout: each bearing tagged by shaft and locating role

01 · Shaft positions

Gearbox bearing selection by shaft position

The right NTN bearing depends on where it sits: which shaft, which end and whether it works as a pair. Pick a position below to see its load pattern, the bearing types typically used there and what to check before you buy.

Gearbox input shaft with bearing seats at drive end
Scenario 01

Input shaft bearings

The input shaft receives drive from the motor side and usually runs at the highest speed in the reducer, while gear mesh forces load the bearings radially.

Load pattern
Radial gear loads at the higher-speed end of the drive train; combined loads where helical gears add axial force.
Typical NTN types
Cylindrical rollerTapered rollerDeep groove ball (small reducers)
  • Quote the full NTN designation, including clearance and cage suffixes.
  • State which bearing is the locating end on this shaft.
  • Attach a marking photo if the nameplate or ring marking is incomplete.
Reducer intermediate shaft carrying two gear stages
Scenario 02

Intermediate shaft bearings

The intermediate shaft carries one gear in mesh with the input stage and another with the output stage, so its bearings see loads from both meshes at once.

Load pattern
Combined radial and axial loads from two gear stages; the arrangement must take axial force in the right direction.
Typical NTN types
Tapered rollerCylindrical rollerSpherical roller
  • Mark tapered bearings used as a pair as one arrangement, not two single items.
  • Keep the original suffix for every bearing; do not mix base designations.
  • Give the quantity per shaft and per gearbox.
Heavy reducer output shaft and bearing housing
Scenario 03

Output shaft bearings

The output shaft turns slowest and carries the highest torque. Its larger, heavier shaft is often where some misalignment has to be accommodated.

Load pattern
Heavy radial loads, combined loads from the final gear stage, and possible shaft or housing misalignment.
Typical NTN types
Spherical rollerTapered rollerCylindrical roller
  • Confirm clearance and cage suffix against the original specification, not workshop records alone.
  • Note paired or matched arrangements on the output side.
  • Give a required-on-site date so the quote can state availability against it.
Locating and non-locating bearing positions on a gear shaft
Scenario 04

Locating and non-locating ends

On each shaft, one bearing fixes the shaft axially (locating) while the other lets it move to allow for thermal expansion (non-locating). An overhaul list that does not separate the two invites wrong fitting or wrong selection.

Load pattern
Locating end: axial plus radial load. Non-locating end: mainly radial load with axial float.
Typical NTN types
Locating · Angular contact ballLocating · Tapered rollerNon-locating · Cylindrical roller
  • Label every line in the list as locating or non-locating.
  • Check that the cylindrical roller design matches the original (rib configuration is part of the designation).
  • Any change of type at either end needs buyer approval first.
Matched pair of tapered roller bearings prepared for a reducer
Scenario 05

Paired arrangements

Bearings mounted as a pair work as one unit. Quoted as unrelated single pieces, the pairing and arrangement requirement gets lost, and the set that arrives may not be the set the gearbox was built with.

Load pattern
Combined or axial loads in both directions, shared across the pair.
Typical NTN types
Tapered roller pairsAngular contact ball pairs
  • State the arrangement (e.g. back-to-back or face-to-face) as specified for the equipment.
  • Count quantity in sets as well as pieces.
  • Ask for any alternative pair to be quoted and marked separately.

02 · Operating conditions

Operating condition to NTN bearing type

Each load condition in a gearbox points to a bearing type. Use this table as a first check, then confirm against the NTN designation specified for the original equipment.

Operating condition NTN bearing type Typical gearbox position
Radial loadCylindrical rollerGear shafts and radial load positions
Combined loadTapered rollerDrive arrangements carrying radial and axial load together
Heavy shaft and misalignmentSpherical rollerHeavier shafts and conditions with some misalignment
Defined locating positionAngular contact ballClearly defined locating positions
Specific axial loadThrustPositions with a specific axial load requirement
Compact spaceNeedle rollerCompact drive components

Deep groove ball bearings are also supplied for auxiliary drives and small reducers.

Sample gearbox overhaul parts list grouped by input, intermediate and output shaft
Sample overhaul list: bearings grouped by shaft, end and pair

03 · Overhaul lists

Quote the whole reducer as one coordinated list

You can send every bearing for a full gearbox overhaul in one enquiry. Input, intermediate and output shaft bearings, and paired sets, are quoted together as one coordinated parts list, so you deal with one NTN authorized distributor instead of several suppliers.

  1. 01Group lines by shaft: input, intermediate, output.
  2. 02Mark each line as locating or non-locating.
  3. 03Flag paired bearings and their arrangement as one set.
  4. 04Give the full NTN designation with suffix, plus quantity per gearbox.
  5. 05Add destination country, postcode and required-on-site date.

Written quotation includes

Product designation, quantity, price and currency, availability, estimated lead time, quote validity, and applicable shipping or tax terms. Ask which product documents are available for your order.

Send Your Overhaul Parts List →

04 · Who uses this

How each customer type uses shaft-position quoting

Repair shops, heavy drive operators, equipment users and distributors all buy NTN gearbox bearings from oemntn.com the same way: by shaft position and original specification. Scroll to see what each one sends.

  • Gearbox repair workshop with reducer opened for overhaul

    Gearbox and reducer repair shops

    • Repair lead maps each bearing to its shaft.
    • Sends the full overhaul list in one enquiry.
    • Attaches marking photos for unclear designations.
  • Heavy machinery drive train with large reducer

    Heavy machinery drive customers

    • Reliability engineer reviews operating conditions.
    • Approves any deviation from original specification.
    • Focuses on output shaft and paired sets.
  • Plant maintenance team planning reducer bearing replacement

    Industrial equipment users

    • Plans replacements around maintenance schedules.
    • States a required-on-site date in the enquiry.
    • Checks labels and quantity on receipt.
  • Bearing distributor warehouse shelves with boxed bearings

    Bearing distributors

    • Technical buyer checks exact designation and set quantity.
    • Receives alternatives marked separately.
    • Confirms shipping documents needed per order.

05 · Specification fidelity

Size-only quoting vs original NTN execution quoting

A bearing that fits the housing is not necessarily the bearing the gearbox was specified with. oemntn.com quotes the NTN execution, suffixes and arrangement of the original equipment, and never substitutes without your approval.

Generic supplier

Quoting by size only

  • ✕Bore, OD and width matched; suffixes ignored.
  • ✕Paired bearings quoted as unrelated single pieces.
  • ✕Locating and non-locating ends not separated.
  • ✕Technical substitutions made without buyer confirmation.
  • ✕Incomplete designations quoted on a guess.

oemntn.com · NTN authorized distributor

Quoting by original NTN execution

  • ✓Full NTN designation kept, including clearance and cage suffixes.
  • ✓Paired bearings quoted as a set with their arrangement.
  • ✓Each line tied to its shaft and locating role.
  • ✓Technical changes only with buyer approval; alternatives marked separately.
  • ✓Identification gaps closed with you before the quote is accepted.

06 · Bearing categories

NTN bearing categories for gearboxes and reducers

Browse NTN bearing categories by type. oemntn.com currently lists 112 products across 27 categories.

Ball BearingsBall Bearings77 modelsRoller BearingsRoller Bearings35 modelsSpecial BearingsSpecial Bearings32 modelsBearings by IndustryBearings by Industry13 modelsAutomotive Bearings and PartsAutomotive Bearings and Parts1 modelSuper-Precision BearingsSuper-Precision Bearings1 model

07 · Related products

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08 · FAQ

Reducer bearing enquiry questions

A complete, well-labelled list is the fastest route to an accurate written quotation.

What should a complete reducer bearing list include?+

A complete list includes the reducer model, shaft position of each bearing, the full NTN designation with suffixes, paired arrangements, the overhaul parts drawing and quantities. Add the destination country, postcode and required-on-site date. Where a designation is incomplete, attach clear photos of the bearing markings.

How should paired bearings be identified in an enquiry?+

List paired bearings as one set, with the shaft position and the arrangement specified for the equipment. Give the quantity in sets as well as pieces. This keeps the pairing requirement in the quotation instead of breaking it into unrelated single items.

Will you substitute a different bearing if the original is unavailable?+

Not without your approval. Any alternative is quoted and marked separately from the original NTN designation, and any technical change needs buyer approval before the order goes ahead.

09 · Enquiry

Send Your Gearbox Model & Shaft Positions

Send your reducer model and bearing list by shaft position. We close any identification gaps with you first, then issue a written quotation from oemntn.com, NTN authorized distributor in Hong Kong.

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