Sources and method

Every standard, chart and manual page the site uses, where it comes from, and how the numbers are worked out from it.

Sources checked

Bolt strength

  1. Portland Bolt: SAE J429: proof load, yield and tensile strength for Grades 2, 5 and 8 (checked October 14, 2026)
  2. Fastenal: Mechanical properties of inch fasteners, with UNC and UNF tensile stress areas (checked October 14, 2026)
  3. Fastenal: Mechanical properties per ISO 898-1 (externally threaded fasteners): proof stress by property class (checked October 14, 2026)
  4. Engineering Toolbox: Metric bolts: minimum ultimate tensile and proof loads, with ISO 898-1 stress areas (checked October 14, 2026)

Threads and stress areas

  1. Portland Bolt: Thread pitch chart: UNC and UNF threads per inch and tensile stress areas (checked October 14, 2026)
  2. Engineering Toolbox: ISO 724 metric threads: coarse and fine pitches with tensile stress areas (checked October 14, 2026)
  3. Engineering Toolbox: Threaded bolts: tensile stress area formulas for unified and ISO metric threads (checked October 14, 2026)

Torque method and nut factors

  1. Fastenal: Torque–tension relationship for A307 A, Grade 5, 8 and 9 coarse thread bolts (75% of proof load; K 0.15 and 0.20) (checked October 14, 2026)
  2. Fastenal: Torque–tension relationship for metric fasteners, property classes 4.6, 8.8, 10.9 and 12.9 (checked October 14, 2026)
  3. Portland Bolt: Bolt torque chart: T = KDP at 75% of proof load, with K for plain, waxed and galvanized bolts (checked October 14, 2026)
  4. Fastenal: Bolted joint design: nut factor (K) by finish and how much preload varies at a given torque (checked October 14, 2026)

Grade markings and units

  1. Bolt Depot: Bolt grade markings and strength chart (checked October 14, 2026)
  2. NIST: Guide to the SI (SP 811), Appendix B.8: conversion factors for units listed alphabetically (checked October 23, 2026)

Torque wrenches

  1. Tekton: Micrometer Torque Wrenches Product Manual: setting the value, applying torque, storage and off-axis correction (checked October 23, 2026)
  2. ELORA: Calibration service: how often a torque wrench should be checked under DIN EN ISO 6789:2017 (checked October 23, 2026)
  3. Atlas Copco: STpad user guide: ISO 6789-2:2017 parameters for click wrenches (test torques and maximum deviation) (checked October 23, 2026)

Owner’s manual pages quoted in the guides

  1. Honda: 2022 Civic Sedan Owner’s Manual: If a Tire Goes Flat (checked October 14, 2026)
  2. Kia: Telluride 2022 Owner’s Manual: Changing tires (checked October 14, 2026)
  3. Mazda: 2025 Mazda CX-50 Owner’s Manual: Changing a Flat Tire (checked October 14, 2026)
  4. Ford: 2019 Explorer Owner’s Manual: Wheels and Tires, Technical Specifications (checked October 14, 2026)
  5. Mercedes-Benz: GLC Coupe Operator’s Manual (C254 MBUX, built from June 2026): Changing a wheel, PDF pages 692–694 (checked October 23, 2026)
  6. Polestar: 2025 Polestar 2 Owner’s Manual: Wheel bolts (checked October 23, 2026)
  7. Polestar: 2025 Polestar 3 Owner’s Manual: Changing wheels (checked October 23, 2026)
  8. Genesis: 2025 GV80 Owner’s Manual: Changing Tires (checked October 23, 2026)

How the bolt torque is worked out

Each value comes from the short-form torque–tension equation, T = K × D × F. The clamp load F is 75% of the bolt’s proof load: its tensile stress area times the proof stress for its grade. Stress areas use the standard formulas, 0.7854 × (D − 0.9743 ÷ n)² for inch threads and π/4 × (d − 0.9382 × P)² for metric, rounded the way the published tables print them. Proof stresses are SAE J429’s and ISO 898-1’s, including the steps down for larger diameters. The nut factor K is 0.20 for dry steel, 0.15 oiled, 0.10 waxed and 0.25 hot-dip galvanized.

The same inputs give the same numbers as Fastenal’s published torque charts, and the site’s automated tests check a sample of their rows, inch and metric, on every change. Unit conversions use the exact definitions of the pound-force, foot and inch.

How lug nut values are collected

Every lug nut value was read on the automaker’s own site, in the online owner’s manual or its PDF for that model and model year. Nothing comes from forums, tire shops or other lists, and nothing is carried over from a neighboring year, trim or sister model. Where a manual names no model year, as Tesla’s online manuals don’t, the page says “current owner’s manual”. Mercedes-Benz lists its manuals by the date the car was built (“2026 October”, or just “2013” for older ones) rather than by model year, so each Mercedes value is listed under that build date.

Each value is stored as printed, in every unit the manual gives, with the page’s address and the date it was read. Where a manual leaves a unit out or prints it wrongly (a few Hyundai tables give only kgf·m, or print 107~127 N·m as “07~127”), the page shows the units it prints and works the missing one out from them, labeled converted. The build checks that the units agree with each other and that every vehicle page links each manual page it quotes. Every one of the 3995 pages was read a second time and compared with the stored value before it went on the site. PDF manuals are linked to the exact page, so the link opens where the value is printed.

443 models in all. Each model’s page lists the manual pages it comes from, year by year.

Corrections log

  • : Three more makes: 50 owner’s manual pages from Toyota, Lexus and Subaru, each read twice on its page. Toyota and Lexus: the 2022–2026 RAV4, Highlander, Grand Highlander, Corolla, Corolla Cross, Tacoma, Tundra and 4Runner and the Lexus RX, ES, GX and TX, from the HTML editions of their owner’s manuals on toyota.com and lexus.com (Toyota’s PDFs refuse requests from outside the US, so the years and models with no HTML edition aren’t listed yet). The Tacoma, Tundra and 4Runner manuals give one value for steel wheels and one for aluminum, and the pages list both; the RX moved from wheel nuts to wheel bolts and to a higher torque in 2023. Subaru: the 2022–2026 Outback, Forester, Crosstrek, Ascent and WRX, from the manual PDFs subaru.com lists for each model year. No earlier value changed.
  • : Honda and Acura back to 2000: 159 more owner’s manual pages, from the 2000–2009 manual PDFs mygarage.honda.com lists, read on techinfo.honda.com, each read twice on its page. New models: the Acura CL, NSX and RSX and the Honda Accord Hybrid; the Acura 3.2 TL and 3.5 RL join the TL and RL, the older Passport and Integra join their models, and the Civic Si hatchbacks are the Civic’s hatchback version. Every manual prints a value: 80 lb-ft (108 N·m) in most, 94 lb-ft (127 N·m) in some Odyssey, Pilot, Ridgeline, MDX, RL and TL manuals, and 87 lb-ft (118 N·m) in the Isuzu-built Passport. No earlier value changed.
  • : Ford 2007 to 2012: 94 more owner’s manual pages, from the newest printing of each owner guide ford.com lists for the rest of 2007 and for 2008–2012, each read twice on its page. New models: the Taurus X, Fusion Hybrid and Focus Electric. The E-Series guides give one value for conical and one for two-piece lug nuts, and the pages list both; the Super Duty goes from 150 lb-ft (200 N·m) in 2008 to 165 lb-ft (224 N·m) from 2009, and the 2010 Transit Connect guide prints 66 lb-ft (90 N·m) where 2011 and 2012 print 100 lb-ft (135 N·m). No earlier value changed.
  • : Porsche, from its international manuals: 279 owner’s manual pages from manual.porsche.com, every edition of the 718, 911, 918 Spyder, Taycan, Panamera, Macan, Macan Electric, Cayenne and Cayenne Electric it lists in British English (2013 to 2027), each read twice on its page; the older Boxster and Cayman are listed as models of their own. Porsche publishes several editions a model year, each for cars built in a stated period, so each row names its period. Models with central-lock wheels (the GT3, Turbo models and 918 Spyder among them) show the central bolt’s or nut’s torque as its own row. Five 2018–2020 911 manuals and three 2024 Taycan manuals misprint the torque in the check after a wheel change; their rows give the tightening step’s value, and the pages say so. Two editions, the May 2014 911 Turbo’s and the January 2014 Macan’s, wouldn’t open, so they aren’t listed. No earlier value changed.
  • : Honda and Acura back to 2010: 141 more owner’s manual pages, from the 2010–2017 manual PDFs on techinfo.honda.com, each read twice on its page. New models include the Acura RL, TL, TSX and TSX Sport Wagon and the Honda Element, CR-Z, Crosstour and Civic Hybrid; Accord and Civic coupes and sedans join their models as versions. The hybrids, EVs and fuel-cell cars that carry a tire repair kit instead of a spare, the 2017 NSX and 2012 TSX Sport Wagon, and the CNG supplements print no wheel nut torque, so they aren’t listed. No earlier value changed.
  • : Older Ford and Lincoln years: 124 more owner’s manual pages, from the owner guides ford.com lists for 2000–2007 Fords and lincoln.com lists for 2000–2012 Lincolns (the newest printing of each), each read twice on its page. New models include the Crown Victoria, Excursion, Freestar, Five Hundred, Freestyle, Thunderbird, Escape Hybrid, Explorer Sport Trac, Ford GT, Lincoln LS, Town Car, Mark LT, Zephyr and MKZ Hybrid. Most 2000–2003 manuals print no lug nut torque, so those years aren’t listed. Some tables give a range, and some print N·m first; each row quotes its table as printed. No earlier value changed.
  • : Mitsubishi, from Canadian manuals: 38 owner’s manual pages from the Canadian editions on Mitsubishi Motors Canada’s site (the Outlander, Outlander PHEV, Eclipse Cross, RVR, Mirage, Mirage G4, Lancer, Lancer Evolution and Lancer Sportback from 2015, and the 2027 Eclipse Sportback), each read twice on its page. Each Mitsubishi page says the values come from Canadian editions: a car sold in another country comes with that country’s edition. The 2022 Outlander’s, 2023–2025 Outlander PHEV’s and 2016–2017 i-MiEV’s manuals print no wheel nut torque, so those years aren’t listed. No earlier value changed.
  • : One more new make: 3 owner’s manual pages from Lucid’s current manuals for the Air, the Air Sapphire and the Gravity, linked from lucidmotors.com’s “Essentials” pages and each read twice. Like Tesla’s, they name no model year: each applies to every Air or every Gravity. They give the torque in N·m only, so the lb-ft shown is worked out from it and labeled converted. No earlier value changed.
  • : Wheel nuts or wheel bolts: each vehicle page now names the fastener its own manual pages name. The Genesis models other than the G70, the Fiat 500, Dodge Dart and Jeep Renegade said wheel nuts, where their manuals say wheel bolts; 17 models whose manuals print “Lug Nut/Bolt” without saying which now say “nut/bolt”, as the manuals do. No torque value changed.
  • : Two more new makes: 15 more owner’s manual pages from Polestar’s online manuals (the Polestar 1, 2, 3 and 4, 2020 to 2026) and Rivian’s owner’s guides (the R1S and R1T for 2022–2024 and 2025–2027, and the 2027 R2), each read twice on its page. Rivian’s guides give the torque in N·m only: the lb-ft shown is worked out from it and labeled converted. No earlier value changed.
  • : Tenth batch of vehicles, two new makes: 300 more owner’s manual pages from Infiniti and Volvo, 2007 to 2027, each read twice on its page. The 2011–2013 Volvo C30, C70 and S40 and the 2011 V50 manuals give one value for each type of wheel nut, and the pages list them by type. No earlier value changed.
  • : Mercedes-Benz manuals left out of the first Mercedes batch: 9 more owner’s manual pages, each read twice on its page. Eight are manuals that give N·m only (the March 2018 A-Class Sedan, August 2014 C-Class Coupe, March 2020 C-Class Sedan, September 2015 CLA Coupe, August 2015 CLS Coupe, July 2018 GLE SUV, August 2014 GLK SUV and March 2015 SLK Roadster), shown with the lb-ft worked out from the N·m and labeled converted; the ninth is the April 2026 CLA Sedan’s, from the file its page’s “Owner’s Manual PDF” button opens. Three editions now cite that file too, in place of another one mbusa.com keeps for the same edition: the September 2026 CLA Sedan and March 2025 CLE Coupe print the same values, and the July 2025 GLC SUV’s prints 110 lb-ft (150 N·m) where the other file printed 111 lb-ft.
  • : Mercedes-Benz: 554 more owner’s manual pages from mbusa.com, 24 models built 2010 to 2027, each read twice on its page. mbusa.com files each manual under the date the car was built rather than a model year, so the pages list them by build date. No earlier value changed.
  • : Hyundai manuals whose table leaves a unit out or misprints one, left out until now: 25 more owner’s manual pages (the 2019–2025 Nexo, 2017–2019 Ioniq Electric and 2019–2021 Kona Electric, which print the N·m as “07~127”; the 2019–2020 Elantra GT, in kgf·m only; the 2021–2023 Santa Fe Hybrid, 2021–2022 Santa Fe Plug-in Hybrid and 2022–2023 Tucson Plug-in Hybrid, with no lb-ft; the 2022–2023 Santa Cruz and the 2027 Elantra, with no N·m), each read twice on its page. Each shows what the manual prints, and the missing unit worked out from it, labeled converted. No earlier value changed.
  • : Ninth batch of vehicles: 16 more owner’s manual pages from Jeep, Chrysler, Ram, Dodge and Fiat, the model years mopar.com lists that weren’t here yet (ten 2026 manuals, the 2024–2025 Charger, the 2023–2025 ProMaster and the 2023 500X), each read twice on its page. No earlier value changed.
  • : Eighth batch of vehicles: 27 more owner’s manual pages, from the 2027 manuals Chevrolet, GMC, Ford, Hyundai, Mazda, Nissan, Jeep, Ram, Dodge and Chrysler have published for models already here, each read twice on its page. No earlier value changed.
  • : Seventh batch of vehicles: 134 more owner’s manual pages from Mazda, Jeep, Ram, Dodge, Chrysler and Fiat back to the 2010 model year, and from Hyundai’s 2014–2021 manuals on owners.hyundaiusa.com, each read twice on its page (the 2010 and 2012 Challenger and Charger SRT8 manuals, the 2010 Grand Cherokee SRT8 and Viper manuals and the 2017 Tucson Fuel Cell manual print no wheel nut torque). No earlier value changed.
  • : Sixth batch of vehicles: 116 more owner’s manual pages from Honda and Acura, every model year from 2018 on that wasn’t here yet (the Clarity, NSX and 2025 CR-V e:FCEV manuals print no wheel nut torque), each read twice on its page. The instructions listed for the earlier Honda and Acura pages are now quoted as printed. No earlier value changed.
  • : Fifth batch of vehicles: 156 more owner’s manual pages from Genesis, Hyundai, Fiat and Alfa Romeo, reaching back to the 2013 model year for Fiat and 2018 for Hyundai, each read twice on its page. No earlier value changed.
  • : Fourth batch of vehicles: 324 more owner’s manual pages from Kia, Mazda, Jeep, Ram, Dodge and Chrysler, reaching back to the 2013 model year (2014 for Kia), each read twice on its page. No earlier value changed.
  • : Third batch of vehicles: 960 more owner’s manual pages from Chevrolet, GMC, Buick, Cadillac, Ford, Lincoln and Nissan, reaching back to the 2007 model year for GM and 2013 for Ford, Lincoln and Nissan, each read twice on its page. No earlier value changed.
  • : Second batch of vehicles: 383 more owner’s manual pages from Ford, Chevrolet, GMC, Nissan, Hyundai, Jeep, Ram, Dodge and Chrysler, each read twice on its page. No earlier value changed.
  • : Site launched with bolt torque for 28 sizes and lug nut torque from 88 owner’s manual pages, each re-read on its page before launch.

Found a number that doesn’t match its source? Tell us. Sources last checked October 14, 2026.