{
 "version": "2026-10-20",
 "license": "Dimension sheets: CC BY 4.0. Standard and published-size files: CC BY 4.0. Xem Studio's own designs (files_license = Xem Studio Design License): free to use and sell things from, not to redistribute as files — https://xemstudio.com/license/. Other publishers' files: their own license, linked beside them.",
 "slug": "anti-ackermann",
 "name": "Reverse (anti-) Ackermann",
 "kind": "standard",
 "category": "Car design",
 "group": "Suspension geometry",
 "year": null,
 "question": "Why do some race cars use anti-Ackermann steering?",
 "tags": [
  "vehicle design",
  "suspension geometry",
  "rc design",
  "aerodynamics"
 ],
 "aliases": [
  "anti ackermann",
  "reverse ackermann",
  "parallel steer",
  "anti-ackermann race car",
  "negative ackermann",
  "ackermann percentage",
  "slip angle steering",
  "parallel steering geometry"
 ],
 "overall_mm": {
  "length": null,
  "width": null,
  "height": null
 },
 "official_cad": false,
 "xem_status": "free-files",
 "les": false,
 "free_files": 1,
 "url": "https://xemstudio.com/objects/anti-ackermann/",
 "sheet_txt": "https://xemstudio.com/objects/anti-ackermann/sheet.txt",
 "sheet": {
  "basis": "Design rules and figures from the cited sources; example geometry by Xem Studio",
  "overall_mm": {
   "length": null,
   "width": null,
   "height": null
  },
  "notes": [
   "At high cornering speed the outside front tyre carries more load and wants a larger slip angle, so pure Ackermann is not ideal. Some racing cars use reverse Ackermann to offset the slip-angle difference, which cuts tyre temperatures in fast corners but hurts low-speed performance (Wikipedia).",
   "On RC cars, less Ackermann gives smoother turn-in, more mid-corner stability and more even front tyre wear (CompetitionX).",
   "The file is a reference example built by Xem Studio from the numbers above (Reference 1/10 touring car: wheelbase 260 mm (AARCMCC ISTC 250-270), track 190 mm (EFRA width without body), 50 mm = EFRA rim limit.). Sizes the sources do not fix are illustrative; scale the example to your own vehicle."
  ],
  "table": {
   "columns": [
    "parameter",
    "value or range",
    "source"
   ],
   "rows": [
    [
     "Reverse Ackermann use",
     "high-speed corners; worse at low speed",
     "Wikipedia"
    ],
    [
     "Less Ackermann (RC)",
     "smoother turn-in, more stable, even tyre wear",
     "CompetitionX"
    ]
   ]
  }
 },
 "sheet_text": "Reverse (anti-) Ackermann — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/anti-ackermann/  (sheet CC BY 4.0; files Xem Studio Design License, https://xemstudio.com/license/)\nBasis: Design rules and figures from the cited sources; example geometry by Xem Studio\nCatalog version: 2026-10-20\n\nSizes: see table below\n- At high cornering speed the outside front tyre carries more load and wants a larger slip angle, so pure Ackermann is not ideal. Some racing cars use reverse Ackermann to offset the slip-angle difference, which cuts tyre temperatures in fast corners but hurts low-speed performance (Wikipedia).\n- On RC cars, less Ackermann gives smoother turn-in, more mid-corner stability and more even front tyre wear (CompetitionX).\n- The file is a reference example built by Xem Studio from the numbers above (Reference 1/10 touring car: wheelbase 260 mm (AARCMCC ISTC 250-270), track 190 mm (EFRA width without body), 50 mm = EFRA rim limit.). Sizes the sources do not fix are illustrative; scale the example to your own vehicle.\n\nparameter  value or range  source\nReverse Ackermann use  high-speed corners; worse at low speed  Wikipedia\nLess Ackermann (RC)  smoother turn-in, more stable, even tyre wear  CompetitionX\n\nFiles elsewhere (not hosted by Xem Studio; license as stated by the publisher):\n- Wikipedia: Ackermann steering geometry — web — Publisher's page; dimensions are facts — https://en.wikipedia.org/wiki/Ackermann_steering_geometry\n- CompetitionX: RC Ackermann Steering Explained — web — Publisher's page; dimensions are facts — https://www.competitionx.com/?p=14\n\nFree files (Xem Studio Design License, Xem Studio; STEP + STL, 1 parts): https://xemstudio.com/files/hardware/anti-ackermann/index.json\nAPI: https://xemstudio.com/api/geometry?object=anti-ackermann\n",
 "sources": [
  {
   "publisher": "Wikipedia",
   "title": "Ackermann steering geometry",
   "url": "https://en.wikipedia.org/wiki/Ackermann_steering_geometry",
   "formats": [
    "web"
   ],
   "license": "Publisher's page; dimensions are facts",
   "license_verified": true,
   "hosted": false
  },
  {
   "publisher": "CompetitionX",
   "title": "RC Ackermann Steering Explained",
   "url": "https://www.competitionx.com/?p=14",
   "formats": [
    "web"
   ],
   "license": "Publisher's page; dimensions are facts",
   "license_verified": true,
   "hosted": false
  }
 ],
 "xem": {
  "status": "free-files",
  "sheet_free": true,
  "mesh_price_usd": null,
  "step_price_usd": null,
  "tolerance_mm": null
 },
 "related": [
  "camber",
  "caster",
  "kick-up",
  "toe-front",
  "toe-rear",
  "ackermann"
 ],
 "fits": [],
 "dimensions": "exact (nominal, no printing tolerance)",
 "dimension_rule": "All geometry on Xem Studio is exact (nominal, true size) with no printing tolerance. Where a part meets another part, the object lists its mating features (feature, exact size, what it mates with, fit class: press, slide, run, socket, clamp or designed). Apply your process's allowance to those features only; 'designed' gaps are part of the design and stay as drawn.",
 "mating": [],
 "faq": [
  {
   "q": "Is parallel steer the same as anti-Ackermann?",
   "a": "Parallel steer sits between the two; the sources describe reduced and reverse Ackermann for high-speed cornering."
  }
 ],
 "files_license": {
  "name": "Xem Studio Design License",
  "holder": "Xem Studio",
  "url": "https://xemstudio.com/license/",
  "note": "Xem Studio's own design: free to use, print, modify and sell things made from it; not to be republished or redistributed as files."
 },
 "offers": [
  {
   "file": "anti-ackermann-geometry",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "Xem Studio Design License",
   "step": "https://xemstudio.com/files/hardware/anti-ackermann/anti-ackermann-geometry.step",
   "stl": "https://xemstudio.com/files/hardware/anti-ackermann/anti-ackermann-geometry.stl",
   "note": "Ackermann demo: inner wheel 30°, outer wheel per the Ackermann relation for wheelbase 260, track 190 (illustrative layout)"
  }
 ],
 "markdown": "https://xemstudio.com/objects/anti-ackermann/index.md"
}