GMC Sierra 1500 — Bolt Pattern & Wheel Fitment

2019-2024 4th gen (T1XX)

TORQUE CONFIRMED INDEPENDENTLY; FITMENT GEOMETRY STILL UNCONFIRMED, SO verified=false. I did not re-use the first researcher's discovery path: I extracted GM's own manual-search endpoint from the gma-cs-mmy-selector-v2.js widget embedded on gmc.com (solrAPI = contentdelivery.ext.gm.com/bypass/gma-search-api/searchapi/solr), queried GM's index myself, and downloaded the PDFs from GM's CDN. 140 lb-ft (190 N-m) is stated in the Capacities and Specifications table of the GMC-badged 2019 (p.436), 2022 (p.458), 2024 (p.444) and 2025 (p.436) Sierra 1500 owner's manuals that I opened myself. NOT assumed from the Silverado T1 record - GM does publish separate Sierra books with their own GMNA part numbers. NO ALLOY/STEEL OR SPARE SPLIT: I verified this programmatically rather than by eye - across every manual the only lb-ft figures in the entire book are "140 lb ft" (wheel nuts) and "6 lb ft" (the nut on a trailer TPMS sensor stem, nothing to do with the vehicle's wheels). The truck carries a full-size spare, so one torque covers every wheel. lugTorqueSteel is therefore deliberately absent. NOT OEM-SOURCED, DO NOT TREAT AS VERIFIED: boltPattern 6x139.7 / 6x5.5, centerBore 78.1 mm and threadPitch M14x1.5 are aftermarket-consensus candidate values only. Beyond the owner's manuals and the 2020/2022/2023/2024 Electrical Body Builder Manuals, I checked a document class the first researcher missed entirely - GM's Incomplete Vehicle Documents for T1XX, MY2019-2024, GM's FMVSS Part 568 filings - and they contain no bolt circle, bore, offset or thread figure either. A caution about false positives: the only "M14" text in the body builder manuals is the connector name "M14A Pickup Box Endgate Lock Actuator", which must not be mistaken for a stud thread spec. accessories.gmc.com still returns HTTP 403 to automated fetching and remains unchecked. OFFSET DOWNGRADED: I changed oemOffset from the first researcher's "24-28" to the "unverified" sentinel. No GM document states an offset, the range has no OEM basis, and the researcher's own note concedes it does not cover the 2022+ AT4X's AEV-branded 18-inch wheel - publishing a fake-precise range on a fitment site is worse than publishing nothing. Candidate range retained here for reference only: roughly 24-28 mm for common 18/20-inch fitments, with the AT4X explicitly outside it. GENERATION-ADJACENT WARNINGS - one of these CORRECTS the first researcher: (1) It is NOT true that MY2019 was the only year with two different trucks called Sierra 1500. GM also published a separate 2022 GMC Sierra 1500 Limited owner's manual (GMNA-15664242, asset 85116171C) alongside the 2022 Sierra 1500 book; the 2022 Limited is the PRE-REFRESH T1 carried over (engines L3B/L82/L84/L87), not a K2XX. Its torque is also 140 lb-ft, which I verified. (2) The MY2019 "Sierra Limited 1500" IS the K2XX carryover (engines L83/L96/LC8) and is a different generation; I verified its 140 lb-ft myself, so this ambiguity is not dangerous for torque - but its manual is a COMBINED book that also covers the 2500HD/3500HD, which are 8-lug trucks, so nothing in that book may be used to infer 1500 wheel geometry. (3) The 4th gen does not actually end in 2024 - the 2025 book (GMNA-18321580) is the same T1 truck with the same 140 lb-ft; the 2019-2024 range here is a database scoping choice, not a real generation boundary. OEM WHEEL LIST EXPANDED: the first researcher listed only a 17-inch steel wheel. GM's Sierra-1500-specific RPO lists also carry 20x9.0 steel (PXT in MY23, 9C1 in MY24 - fleet/police, with a matching 20x9.0 steel spare) and 22x9.0 steel (RBR, in both MY23 and MY24), plus 18-inch RQ8/ULV/WBP and 20-inch NZQ/WGQ/WBP/CWK. The 22-inch steel entry is unusual and should be treated as fleet/special-order. Finally, GM's own manual text warns that when accessory locking wheel nuts are fitted the owner must "Follow the torque specification supplied by the aftermarket manufacturer" rather than the 140 lb-ft figure.