Difference between revisions of "Geo Setups"

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Line 9: Line 9:
 
   <td class=xl25 width=125 style='width:94pt'>340R Road</td>
 
   <td class=xl25 width=125 style='width:94pt'>340R Road</td>
 
   <td class=xl25 width=125 style='width:94pt'>340R Track</td>
 
   <td class=xl25 width=125 style='width:94pt'>340R Track</td>
 +
  <td class=xl25 width=125 style='width:94pt'>Exige S1</td>
 
  </tr>
 
  </tr>
 
  <tr height=17 style='height:12.75pt'>
 
  <tr height=17 style='height:12.75pt'>
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   <td class=xl27>100/110mm</td>
 
   <td class=xl27>100/110mm</td>
 
   <td class=xl27>100/110mm</td>
 
   <td class=xl27>100/110mm</td>
 +
  <td class=xl27>112/122mm</td>
 
  </tr>
 
  </tr>
 
  <tr height=17 style='height:12.75pt'>
 
  <tr height=17 style='height:12.75pt'>
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   <td class=xl27>12°</td>
 
   <td class=xl27>12°</td>
 
   <td class=xl27>12°</td>
 
   <td class=xl27>12°</td>
 +
  <td class=x127>12°</td>
 
  </tr>
 
  </tr>
 
  <tr height=17 style='height:12.75pt'>
 
  <tr height=17 style='height:12.75pt'>
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   <td class=xl27 x:str="'+3.8°">+3.8°</td>
 
   <td class=xl27 x:str="'+3.8°">+3.8°</td>
 
   <td class=xl27 x:str="'+3.7°">+3.7°</td>
 
   <td class=xl27 x:str="'+3.7°">+3.7°</td>
 +
  <td class=xl27 x:str="'+3.8°">+3.8°</td>
 
   <td class=xl27 x:str="'+3.8°">+3.8°</td>
 
   <td class=xl27 x:str="'+3.8°">+3.8°</td>
 
   <td class=xl27 x:str="'+3.8°">+3.8°</td>
 
   <td class=xl27 x:str="'+3.8°">+3.8°</td>
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   <td class=xl27>0°</td>
 
   <td class=xl27>0°</td>
 
   <td class=xl27 x:str="-0.5° "><span lang=EN-GB>-0.5°<span
 
   <td class=xl27 x:str="-0.5° "><span lang=EN-GB>-0.5°<span
   style='mso-spacerun:yes'> </span></span></td>
+
   style='mso-spacerun:yes'> </span></span></td>
 
   <td class=xl27 x:str="'-1.8° "><span lang=EN-GB>-1.8°<span
 
   <td class=xl27 x:str="'-1.8° "><span lang=EN-GB>-1.8°<span
   style='mso-spacerun:yes'> </span></span></td>
+
   style='mso-spacerun:yes'> </span></span></td>
 +
  <td class=xl27 x:str="'-0.5°">-0.1°</td>
 
  </tr>
 
  </tr>
 
  <tr height=17 style='height:12.75pt'>
 
  <tr height=17 style='height:12.75pt'>
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   <td class=xl27>0.2mm OUT overall</td>
 
   <td class=xl27>0.2mm OUT overall</td>
 
   <td class=xl27>0.5mm OUT overall</td>
 
   <td class=xl27>0.5mm OUT overall</td>
 +
  <td class=xl27>0.1mm OUT overall</td>
 
  </tr>
 
  </tr>
 
  <tr height=17 style='height:12.75pt'>
 
  <tr height=17 style='height:12.75pt'>
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   <td class=xl27 x:str="'-1.8°">-1.8°</td>
 
   <td class=xl27 x:str="'-1.8°">-1.8°</td>
 
   <td class=xl27 x:str="'-2.0° "><span lang=EN-GB>-2.0°<span
 
   <td class=xl27 x:str="'-2.0° "><span lang=EN-GB>-2.0°<span
   style='mso-spacerun:yes'> </span></span></td>
+
   style='mso-spacerun:yes'> </span></span></td>
 
   <td class=xl27 x:str="'-2.7° "><span lang=EN-GB>-2.7°<span
 
   <td class=xl27 x:str="'-2.7° "><span lang=EN-GB>-2.7°<span
   style='mso-spacerun:yes'> </span></span></td>
+
   style='mso-spacerun:yes'> </span></span></td>
 +
  <td class=xl27 x:str="'-2.4° "><span lang=EN-GB>-2.7°<span
 +
  style='mso-spacerun:yes'> </span></span></td>
 
  </tr>
 
  </tr>
 
  <tr height=17 style='height:12.75pt'>
 
  <tr height=17 style='height:12.75pt'>
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   <td class=xl27>1.5mm IN each side</td>
 
   <td class=xl27>1.5mm IN each side</td>
 
   <td class=xl27>2.5mm IN each side</td>
 
   <td class=xl27>2.5mm IN each side</td>
 +
  <td class=xl27>1.2mm IN each side</td>
 
  </tr>
 
  </tr>
 
  <tr height=17 style='height:12.75pt'>
 
  <tr height=17 style='height:12.75pt'>

Revision as of 08:40, 5 September 2006

Some standard Geo settings

Geometry Standard S1 & S2 S2 135R 340R Road 340R Track Exige S1
Ride Height F/R 130/130mm 120/120mm 100/110mm 100/110mm 112/122mm
Steering axis inclination 12° 12° 12° 12° 12°
Front Castor +3.8° +3.7° +3.8° +3.8° +3.8°
Front Camber -0.1° -0.5° -1.8° -0.1°
Front alignment/toe 0.2mm OUT Overall 0 mm 0.2mm OUT overall 0.5mm OUT overall 0.1mm OUT overall
Rear Camber -1.8° -1.8° -2.0° -2.7° -2.7°
Rear alignment/toe 1.2mm IN each side 1.2mm IN each side 1.5mm IN each side 2.5mm IN each side 1.2mm IN each side
Bump Steer 2.0° to 2.5° toe in

converting from mm to degrees; divide the toe in mm by the wheel rim diameter in mm then ARC SIN the answer

Geo setting X does Y

Some guidlines although its dependent on many, many other factors

Increasing front camber from the default -0.1° to -0.5° each side will dramatically improve the understeer although the inside edges of the tyres will wear slightly faster.

Increasing rear camber from the default -1.8° to -2.0° (or higher) makes the car more neutral after you've removed the understeer.

Increasing front toe helps with the sharpness of the turn-in

Increasing rear toe cancells out the rear suspension flex when the tyre is loaded which leads to toe out - so running more toe in compensates for that - you don't want toe out at the rear.

Setting your own geo

Whilst a race prep specialist can charge £200 for a Geo you can DIY castor, camber and toe settings.

1. To baseline your current setup www.alignmycar.co.uk will find a local place with a Hunter alignment system who will provide a setup sheet showing castor, camber and toe for £15

2. If you dont have the S1 or S2 service manual suspension sections you really should get them as this is only a small part; http://www.sandsmuseum.com/cars/elise/experience/maintenance/alignment/alignment.html

3. Set the front castor by "shuffeling washers" on the top wishbone pivots.

4. Set the front and rear camber by adding & removing shims (removing a 1mm shim plate will alter camber by approximately -0.25° at the front and -0.30° at the rear).

5. You could set the toe yourself, but since a quarter turn of the track rod alters toe by 2mm its a damned delicate affair without a real time readout.

6. Back to the alignment centre to check your config for another £15 and set your front and rear toe for another £30. You can now alter the camber without materially affecting toe.

MEMO: Someone else can explain how to create a DIY geo rig and set bump steer !