Needle roller bearing inner rings IR and LRT (IR 12x15x16, IR 20x25x26.5, LRT 5812): bore d, raceway diameter F, width B — dimension sheet Source: Xem Studio, https://xemstudio.com/objects/needle-roller-bearing-inner-rings-ir-lrt/ (sheet CC BY 4.0) Basis: SKF IR designations from the Acorn parts list and Koyo LRT rows, cross-checked on IR 5x8x12 = LRT 5812; numbers only (no chamfer r min published in the lists read) Catalog version: 2026-10-20 Sizes: see table below - An IR (SKF, INA) or LRT (Koyo, IKO) ring is the hardened inner ring that goes with an NK or RNA needle bearing when the shaft itself is not hardened and ground. The bearing designation IR d x F x B reads bore, raceway diameter, width; F equals the Fw of the bearing it pairs with (an IR 12x15x16 runs with a bearing of Fw 15). - Numbers: the SKF IR designations as listed on the Acorn Industrial Services parts list (the designation itself carries d, F and B) and the first LRT rows of Koyo's inner-ring table (d, F, B in separate columns). IR 5x8x12 and LRT 5812 are the same size in the two makers. Partial: this is the set of rings read, not the full catalogue. The chamfer r min of the rings is not in the lists read, so there are no files. - Left out: the full IR range (Acorn lists 143 SKF rings in 8 pages; only the designations read are shown), the ring chamfers, oil-hole versions, LRTZ, JR / EG / ER (INA) numbers, rings above 140 mm. inner ring bore d, mm raceway Ø F (= bearing Fw), mm width B, mm an NK / RNA row with this Fw is on the NK page source IR 5x8x12 5 8 12 yes (NK/RNA page) SKF (Acorn listing) IR 8x12x10.5 8 12 10.5 yes (NK/RNA page) SKF (Acorn listing) IR 10x13x12.5 10 13 12.5 — SKF (Acorn listing) IR 10x14x13 10 14 13 yes (NK/RNA page) SKF (Acorn listing) IR 10x14x20 10 14 20 yes (NK/RNA page) SKF (Acorn listing) IR 12x15x16 12 15 16 yes (NK/RNA page) SKF (Acorn listing) IR 12x15x16.5 12 15 16.5 yes (NK/RNA page) SKF (Acorn listing) IR 12x16x16 12 16 16 yes (NK/RNA page) SKF (Acorn listing) IR 17x20x16 17 20 16 yes (NK/RNA page) SKF (Acorn listing) IR 20x25x20.5 20 25 20.5 yes (NK/RNA page) SKF (Acorn listing) IR 20x25x26.5 20 25 26.5 yes (NK/RNA page) SKF (Acorn listing) IR 20x25x38.5 20 25 38.5 yes (NK/RNA page) SKF (Acorn listing) IR 25x30x26.5 25 30 26.5 yes (NK/RNA page) SKF (Acorn listing) IR 30x35x13 30 35 13 yes (NK/RNA page) SKF (Acorn listing) IR 35x40x17 35 40 17 yes (NK/RNA page) SKF (Acorn listing) IR 35x40x20 35 40 20 yes (NK/RNA page) SKF (Acorn listing) IR 40x45x30 40 45 30 — SKF (Acorn listing) IR 40x50x22 40 50 22 — SKF (Acorn listing) IR 50x55x25 50 55 25 — SKF (Acorn listing) IR 50x55x35 50 55 35 — SKF (Acorn listing) IR 50x60x25 50 60 25 — SKF (Acorn listing) IR 55x65x28 55 65 28 — SKF (Acorn listing) IR 60x68x25 60 68 25 — SKF (Acorn listing) IR 60x70x25 60 70 25 — SKF (Acorn listing) IR 65x75x28 65 75 28 — SKF (Acorn listing) IR 80x90x54 80 90 54 — SKF (Acorn listing) IR 110x120x30 110 120 30 — SKF (Acorn listing) IR 140x160x50 140 160 50 — SKF (Acorn listing) LRT 5710 5 7 10 yes (NK/RNA page) Koyo (LRT) LRT 5812 5 8 12 yes (NK/RNA page) Koyo (LRT) and SKF LRT 5816 5 8 16 yes (NK/RNA page) Koyo (LRT) LRT 6810 6 8 10 yes (NK/RNA page) Koyo (LRT) LRT 6912 6 9 12 yes (NK/RNA page) Koyo (LRT) LRT 6916 6 9 16 yes (NK/RNA page) Koyo (LRT) LRT 61010 6 10 10 yes (NK/RNA page) Koyo (LRT) LRT 7910 7 9 10 yes (NK/RNA page) Koyo (LRT) LRT 71012 7 10 12 yes (NK/RNA page) Koyo (LRT) LRT 71016 7 10 16 yes (NK/RNA page) Koyo (LRT) LRT 81011 8 10 11 yes (NK/RNA page) Koyo (LRT) LRT 91211 9 12 11 yes (NK/RNA page) Koyo (LRT) LRT 91212 9 12 12 yes (NK/RNA page) Koyo (LRT) LRT 91216 9 12 16 yes (NK/RNA page) Koyo (LRT) Files elsewhere (not hosted by Xem Studio; license as stated by the publisher): - Acorn Industrial Services (SKF): SKF inner rings for needle roller bearings IR d x F x B (designations as listed) — web — Publisher's page; dimensions are facts — https://www.acorn-ind.co.uk/skf/bearings/roller-bearings/needle-roller-bearings/needle-roller-bearing-components - Koyo (JTEKT), via AIMS Industrial: Inner rings LRT / LRTZ for needle roller bearings: d, F, B (first rows, shaft 5 to 9 mm) — web — Publisher's page; dimensions are facts — https://aimsindustrial.com.au/cdn/shop/files/IKO-Needle-Roller-Bearing-Inner-Rings-Catalogue-Pages-7-to-12-Selected.pdf - McMaster-Carr: Needle bearings (free STEP/IGES per part, for your own design use; no redistribution) — STEP, IGES, PDF — McMaster-Carr site terms: personal design use, no redistribution [verify license at link] — https://www.mcmaster.com/needle-bearings No true-size file yet: the published figures do not fix the whole shape; a measured scan is planned. API: https://xemstudio.com/api/geometry?object=needle-roller-bearing-inner-rings-ir-lrt