The Timken 231 Series is an extra-wide cross-section, double-row, self-aligning spherical roller bearing — wider than the standard 230/222/223 but less ultra-wide than the shock-optimized 232. It combines high radial capacity with significant axial thrust tolerance, making it a go-to for heavy gearbox shafts, large centrifugal pumps, paper-machine drive sections, rolling-mill backup rolls, and large conveyor pulleys in continuous service.

• Construction: Double-row self-aligning, extra-wide section — compensates for shaft misalignment up to 1º while carrying sustained heavy radial plus moderate axial load.
• Cage options: Both brass machined finger (“EM” suffix) and steel stamped window (“EJ” suffix) variants — brass machined standard on larger sizes and shock-prone service.
• Bore types: Both cylindrical (straight) and tapered (“K” suffix) bore variants available across nearly the full range.
• Relubrication: W33 feature (oil groove + three holes in outer ring) standard on most variants; specialty W-feature packs on OEM-specific builds.
• Clearance classes: C0, C2, C3, C4 — C3 or C4 for elevated-temperature and interference-fit mounts.
• Bore range: 100 mm – 480 mm (3.94 in – 18.90 in).
• Width range: 52 mm – 248 mm.
• Typical applications: Heavy gearbox input/output shafts, large centrifugal pumps, paper-machine drive sections, rolling-mill backup rolls, large conveyor pulleys, mixer and agitator drives.

Why 231 vs. 230: The 231 has a wider cross-section and higher axial capacity than the 230 — choose 231 when axial thrust is non-trivial; choose 230 for predominantly radial duty at the same bore.