Difference between revisions of "Geo Setups"

From TechWiki
Jump to navigation Jump to search
Line 92: Line 92:
  
 
== Setting your own geo ==
 
== Setting your own geo ==
Whilst a race prep specialist can charge £200 for a Geo you can DIY Castor, camber and toe settings.
+
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 privide a setup sheet showing Castor, camber and toe for £15
+
1. To baseline your current setup www.alignmycar.co.uk will find a local place with a Hunter alignment system who will privide a setup sheet showing castor, camber and toe for £15
  
If you dont have the S1 or S2 service manaual 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  
+
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  
  
2. Set the front castor by "counting washers"   
+
3. Set the front castor by "shuffeling washers"   
  
3. 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).
+
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).
  
4. 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.
+
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 set bump steer !

Revision as of 19:58, 24 August 2006

Some standard Geo settings

Geometry Standard S1 & S2 S2 135R 340R Road 340R Track
Ride Height F/R 130/130mm 120/120mm 100/110mm 100/110mm
Steering axis inclination 12° 12° 12° 12°
Front Castor +3.8° +3.7° +3.8° +3.8°
Front Camber -0.1° -0.5°  -1.8° 
Front alignment/toe 0.2mm OUT Overall 0 mm 0.2mm OUT overall 0.5mm OUT overall
Rear Camber -1.8° -1.8° -2.0°  -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
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 privide 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"

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 set bump steer !