6068 bearing: complete specifications & equivalents

Specification table

Source: catalog reference (NTN Ball and Roller Bearings CAT.No.2203-3/E (2024)) · extracted 2026-09-25

Parameters extracted from the official NTN Ball and Roller Bearings catalogue (NTN Ball and Roller Bearings CAT.No.2203-3/E (2024)); NTN® is a trademark of NTN Corporation, used here for identification only — mpnbase is not an authorized NTN distributor. Boundary dimensions are ISO 15 interchangeable; current production values may differ, verify at ntnglobal.com.

Cross references & equivalents

Interchange levels: full standard interchange · partial verify parameters · verify manual confirmation required. Links resolve to the equivalent model's specification page where available.

How the 6068 model number is decoded

6068 is supplied open, without shields or seals, so the arrangement around it must supply and retain the lubricant. Within the extra-light 60xx section (diameter series 0 of ISO 15), multiplying bore code 68 by five gives the 340 mm bore; the 520 mm outside diameter and 82 mm width follow the same boundary-dimension plan. For a rotating inner ring on a 340 mm shaft under normal load, catalogue practice seats it on a m6 shaft fit with an H7 housing bore — confirm against the actual load direction and magnitude before committing. In the NTN catalogue this open execution carries the bare designation; protected variants are ordered separately with suffixes ZZ (shields), LLB/LLF (non-contact seals), LLH (low-torque contact seal) and LLU (contact seal).

Typical equipment & failure modes

Selection pitfalls — read before you substitute

• Large bores like the 340 mm of 6068 demand clean, burr-free seats; one raised burr under a ring this size cocks the bearing and concentrates load at the raceway edge, cutting life drastically.
• The 60xx extra-light section at 340 mm bore uses a smaller 520 mm OD than a 6268; load ratings are lower, so do not replace a failed 62-series bearing with a 60-series without re-rating the load.
• Storage matters for open bearings: 6068 leaves the factory with rust preventive only, so clean it and apply the service grease at assembly even if the rings look oily from the wrapper.
• Open bearings tolerate the highest speeds in the 6000-series but need a defined regreasing interval; run-to-failure lubrication is the dominant cause of early failure in open 6068 units.
• The housing bore for the 520 mm OD should be round within IT7; an oval bore pinches the outer ring of 6068 and shows up later as two-point loaded raceway wear.
• Deep-groove ball bearings tolerate only minutes of misalignment; if the 520 mm housing cannot be aligned, switch to a self-aligning type rather than shimming 6068.
• The open 6068 has no integral sealing; in the NTN 2203 catalogue the protected variants carry suffixes ZZ (non-contact steel shields), LLB/LLF (non-contact rubber seals), LLU (contact rubber seals) and LLH (a low-torque contact seal with higher speed capability than LLU). A JR or JRX suffix (printed for some thin-section sizes) denotes a pressed-steel cage, not a seal.
• The 340 mm bore places 6068 in NTN's maximum-size range at the lower end; this is a heavy-engineering bearing where centrifugal force and cage inertia dominate the design envelope. NTN supplies a machined brass cage (suffix M) and expects oil lubrication; do not use catalogue grease speed figures for this size without an NTN engineering review.
• NTN lists the grease limiting speed at 1100 r/min for 6068; this is a large-section size where the pressed-steel cage is speed-limited — NTN recommends the machined brass cage (suffix M) and oil lubrication for any continuous operation above this figure.
• At 465 kN dynamic load rating (C) and 610 kN static (C0), 21.9 kN fatigue load limit Cu, 6068 is a very-heavy-load bearing for large industrial gearboxes and steel-mill equipment; NTN supplies a machined brass cage (suffix M) and expects an application review, because catalogue L10 life alone does not capture the shock and misalignment loads at this rating.
• At 61800 g (61.8 kg), 6068 is an extremely heavy bearing at the top of the single-row deep-groove range; NTN mandates induction heating (max 120 °C), a dedicated lifting fixture, and a machined brass cage (suffix M). Consult NTN engineering for the mounting and handling procedure before installation.
• The 340×520×82 mm envelope of 6068 gives a D/d ratio of 1.53 and 90.0 mm radial section height — this thin section saves space but is sensitive to misalignment and shock; confirm the housing stays round within IT7 and the shaft does not deflect past the raceway contact angle under load.
• The 465/610 kN load ratings, 21.9 kN fatigue load limit Cu NTN lists the grease limiting speed at 1100 r/min for this designation; oil-mist or jet lubrication raises the ceiling but requires a sealed-housing review. and 61800 g mass here are NTN Ball and Roller Bearings CAT.No.2203-3/E figures for 6068 on the 340×520×82 mm ISO 15 envelope; internal geometry and ratings legitimately differ between brands, so re-verify before substituting another manufacturer's 6068 in a rated drive.
• Standard catalogue stock of 6068 is the general-purpose execution; for low-noise motor duty NTN offers low-torque seal and special-grease variants in this size class, which are separate order numbers.
• NTN date-codes its packaging; rotate stock first-in-first-out, because the grease inside sealed units ages on the shelf — after three to five years of storage, check the grease condition before putting the bearing into service.