YAR-208-109-2F bearing: complete specifications & equivalents

Specification table

Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018)) · extracted 2026-09-28

Parameters extracted from the official SKF Rolling Bearings catalogue (SKF PUB BU/P1 17000/1 EN (Oct 2018)); SKF® and SKF Explorer® are trademarks of AB SKF, used here for identification only — mpnbase is not an authorized SKF distributor. Boundary dimensions are ISO 15 interchangeable; current production values may differ, verify at skf.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 YAR-208-109-2F model number is decoded

YAR 208-109-2F is SKF's 39.6875 mm-bore grub-screw insert bearing with the inner ring extended on both sides in the YAR2 series — a Y-bearing with a spherically ground outside surface for static self-alignment inside a matching SKF Y-housing, boundary dimensions 39.6875x80x49.2 mm. Wide-inner-ring deep-groove ball geometry carries the load: the extended inner ring gives the shaft grip and the seal lands, while the outer ring stays narrow and spherically ground on its outside surface. the YAR prefix names SKF grub-screw Y-bearings: two set screws in the extended inner ring lock the shaft at a 120 deg angle, and the inner ring extends symmetrically on both sides. the three-digit -109 tail codes the bore in inches for inch-shaft bearings: 1 whole inch 9/16 in = 39.688 mm (first digit whole inches, next two sixteenths of an inch). suffix -2F means an NBR rubber contact seal plus a plain pressed-steel flinger on EACH side: the lip rides the extended inner ring while the flinger sheds coarse contamination before it reaches the lip. Envelope 39.6875x80x49.2 mm (1.563x3.15x1.937 in), outer ring 21 mm wide, C 30.7 kN, C0 19 kN, Pu 0.8 kN. The catalogue publishes a single speed ceiling, the limiting speed: 4,800 r/min; mass 610 g. Selection figures for YAR 208-109-2F: C0/C is 0.619, Pu 0.8 kN is 2.606 % of the 30.7 kN dynamic rating, and the 610 g catalogue mass works out to roughly 15.37 g per millimetre of the 39.6875 mm bore. Rating split for the maintenance file: dynamic 30.7 kN (L10), static 19 kN (s0 shock check), fatigue 0.8 kN (adjusted life) — three separate uses for YAR 208-109-2F, none interchangeable with another. Static-first planning: the 0.386 kN of C0 per overall-width millimetre is the figure for belt tension peaks and rotor imbalance standstill loads on the 39.6875 mm shaft, not the 30.7 kN L10 value. Capacity density: 30.7 kN from 0.610 kg of bearing steel is about 50.328 kN per kilogram, and per width millimetre the 49.2 mm unit carries 0.624 kN of dynamic capacity. Grease-life arithmetic is dominated by speed: at dn approx 2.87x10^5 the sealed-for-life fill is planned for the catalogue's grease-life regime, which is why the limiting speed and the relubrication interval move together, and high-temperature mounts shorten both even when load is light. Both-sides sealed order-number note: the two set screws clamp through dimpled recesses in the extended inner ring; tighten alternately to the catalogue procedure and retighten after the first run-in period, because the -2F flingers keep dust out but cannot compensate for a screw that walked loose. Set-screw geometry on this size: the two 120 deg screws bear on the 39.6875 mm shaft inside the 49.2 mm total width while the outer ring is only 21 mm wide, leaving the extended ring to carry the screw points clear of the ball track.

Typical equipment & failure modes

Selection pitfalls — read before you substitute

• Replacement discipline: a YAR insert is not interchangeable with an eccentric-collar unit of the same envelope — the shaft may need spot-facing or collar space that does not exist.
• Do not specify the 39.6875 mm grub-screw insert for a shaft harder than about 45 HRC without dimples: the screw points skate on hard surfaces and the unit creeps regardless of tightening torque.
• The 30.2 mm s1 dimension is the screw seating geometry inside the 28.2 mm of extended inner ring; a shaft step that crowds that side prevents the screws reaching the shaft squarely.
• Ordering discipline for the 39.6875 mm size: the chapter lists several executions side by side (YAR2 locking style x seal package x application variant); a bare-number substitution needs a fresh dimension, speed and rating check rather than a like-for-like assumption.