YAT-203 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 YAT-203 model number is decoded

Listed in SKF 17000 chapter 2, YAT 203 is a grub-screw insert bearing with the inner ring extended on one side, 17x40x22.1 mm overall, whose convex spherical outer ring pivots in the spherical bore of a Y-pillow, Y-flange or take-up housing. Construction follows the Y-bearing principle: a capped and flinger-protected deep-groove ball insert, inner ring elongated for the screw points, outer ring convex-spherical for the housing seat. YAT is SKF's grub-screw insert design — a single extended inner-ring side housing the two 120 deg set screws. the size code 203 carries the usual bore arithmetic — 17 mm — while the leading 2 marks the ISO 15 diameter series 2 sphered-OD envelope. the bare designation means no factory seal package: unlike the -2F executions this bearing relies on enclosure by the Y-housing and its own re-greasing path, which is why it is normally specified inside well-sealed plummer and flange units. Envelope 17x40x22.1 mm (0.669x1.575x0.87 in), outer ring 12 mm wide, C 9.56 kN, C0 4.75 kN, Pu 0.2 kN. The catalogue publishes a single speed ceiling, the limiting speed: 9,500 r/min; mass 80 g. Load balance for documentation: C0 4.75 kN against C 9.56 kN gives a 0.497 ratio; mounted-unit positions with shock and standstill loading are normally checked on C0, while conveyor and fan duty are evaluated on the L10 figure. Speed ceiling of 9,500 r/min is the catalogue mechanical limit for THIS execution; seal lip and flinger drag, not steel fatigue, are normally what cap it, so real fan duty is planned well below it. Pitch-diameter arithmetic: dm = (17+40)/2 = 28.5 mm; at the 9,500 r/min limiting speed the ball set runs at dn approx 2.71x10^5, reduced from an open bearing mainly by seal lip friction and the life-long grease fill. Envelope arithmetic: the radial section from 17 mm bore to 40 mm OD is 11.5 mm; dividing C 9.56 kN by that section gives 0.831 kN per section millimetre, and the 22.1 mm overall width is 1.922x the section. Outer-vs-overall width: the outer ring is 12 mm wide inside the 22.1 mm total, so the extended inner ring accounts for 0.457 of the overall width (10.1 mm of axial projection on the locking side). Single-extension fitting note: with the inner ring extended only on the locking side, orient the open (non-extended) face toward the shaft step or housing shoulder as the drawing shows — reversed, the set screws end up unsupported by the abutment and the shortened side offers no seal land at all. Set-screw geometry on this size: the two 120 deg screws bear on the 17 mm shaft inside the 22.1 mm total width while the outer ring is only 12 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

• Do not specify the 17 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 15.9 mm s1 dimension is the screw seating geometry inside the 10.1 mm of extended inner ring; a shaft step that crowds that side prevents the screws reaching the shaft squarely.
• Replacement discipline: a one-side YAT 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.
• Catalogue ratings belong to YAT 203 as the grub one open execution; other order numbers of the YAT 203 size are different articles (open vs sealed, plain vs rubberized flinger, stainless vs carbon steel) and may carry different ratings or speeds — always quote the full designation.