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Product Series of Automation-Related Precision Ball Screws and Linear Rails – High-Precision Ball Screws

NSK Bearings Spherical Roller Bearings 21308K

Product Overview

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Spherical Roller Bearings/Bearings

21308K

Spherical Roller Bearing

NSK Distributor Taiwan

Bore d40 mm
Width B23 mm

Product Features

NSK spherical roller bearing (21308 series), model 21308K: 40 mm bore, 90 mm OD, 23 mm width, tapered bore (K, 1:12 taper)
Basic dynamic load rating Cr 118 kN, basic static load rating C0r 111 kN (NSK official catalog; current-generation equivalent 21308EAKE4, Cr/C0r figures above are taken from that higher-capacity current design)
Thermal speed rating approx. 6700 min⁻¹, limiting speed (grease) approx. 6000 min⁻¹
Double-row rollers on a spherical outer raceway self-align for misalignment and shaft deflection — suited to long shafts and heavy-duty drives
Nahshon is NSK's distributor in Taiwan — add the part number to your inquiry list

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Product Description

The 21308K is an NSK spherical roller bearing from the 21308 series: 40 mm bore, 90 mm outer diameter, 23 mm width, tapered bore (K, 1:12 taper). Basic dynamic load rating Cr is 118 kN and basic static load rating C0r is 111 kN (NSK official catalog CAT. No. E1103d; current-generation equivalent 21308EAKE4, Cr/C0r figures above are taken from that higher-capacity current design). Spherical roller bearings use double-row rollers on a spherical outer raceway that self-aligns for misalignment and shaft deflection while carrying heavy radial and bidirectional axial loads — common in gear reducers, conveyor rollers, paper machinery and wind-turbine main shafts.

Inquiries & customization

Add this part number to your inquiry list — Nahshon is NSK's distributor in Taiwan and works directly with the factory to confirm specifications, stock and pricing.

Product Specifications

Specification	Unit	21308K
Series	-	21308 series
Bore d	mm	40
Outer diameter D	mm	90
Width B	mm	23
Min. chamfer r	mm	1.5
Bore type	-	tapered bore (K, 1:12 taper)
Basic dynamic load rating Cr	kN	118
Basic static load rating C0r	kN	111
Thermal speed rating	min⁻¹	6700
Limiting speed (grease)	min⁻¹	6000

FAQ

What's the difference between the Z, ZZ and DDU suffixes?

Z means a single-side steel shield, ZZ means steel shields on both sides, and DDU means contact rubber seals on both sides. Shields suit general environments and high speeds; rubber seals give better dust and water protection with slightly higher friction torque — choose based on your dust exposure and lubrication method.

When should I choose C3 clearance instead of standard clearance?

For motors or other applications with noticeable temperature rise, or high-speed operation, the inner ring expands from heat and reduces the clearance — choose C3 in that case. Standard clearance is fine for general room-temperature, low-speed use. See Nahshon's technical resources for a clearance selection guide.

Is 21308K in stock in Taiwan? What is the lead time?

Nahshon is the NSK distributor in Taiwan and keeps stock of some commonly used items. Add 21308K to your inquiry list or give us a call, and we'll confirm stock, lead time and quote.

Series Models

Spherical Roller Bearings・21308 series

21304 21305 21306 21306K 21307 21307K 2130821308K（This page）21309 21309K 21310 21310K 21311 21311K 21312 21312K 21313 21313K

View All Spherical Roller Bearings Models →