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Chassis Setup Guide PDF  | Print |  E-mail
Written by Vic R   

This guide makes it easy to improve kart handling for a typical kart in normal conditions.  Only testing will confirm these recommendations.

 

Oversteering at corner entry or there is too much front end bite.

Reduce jacking effect
  • Reduce scrub radius (remove one wheel spacer from both front spindles)
  • Increase rear track width
  • Reduce castor
  • Reduce Ackermann
Increase rear grip
  • Raise rear tyre pressure by 1 PSI or drop front tyre pressure by 1 PSI
  • Move weight towards rear of the kart
  • Remove 3rd Axle bearing (in low grip conditions)
Reduce front grip
  • Lower the front of the chassis
  • Reduce toe-out (1-2mm is normal toe-out)
  • Remove or loosen front torsion bar and loosen crash bar
Driving
  •  Reduce trail braking


 

Understeering at corner entry (pushing out)

Increase jacking effect
  • Increase scrub radius (add one wheel spacer on both front spindles)
  • Increase castor
  • Increase Ackermann
  • Decrease rear track width
Increase front grip
  • Raise front tyre pressure by 1 PSI or drop rear tyre pressure by 1 PSI
  • Shift weight forward (seat, ballast)
  • Raise the front end of the kart
  • Add or tighten front torsion bar and crash bar
  • Use shorter rear hubs or softer axle
  • Increase toe-out (1-2mm is normal toe-out)
Driving
  •  Soother turn in


 

Oversteering out of the corner

Increase rear grip
  • Raise rear tyre pressure by 1 PSI or drop front tyre pressure by 1 PSI
  • Put longer (or shorter) wheel hubs on the axle
  • Add torsion bar or turn torsion bar to vertical position
  • Raise any ballast to a higher vertical position on the rear of the kart
  • Raise the rear ride height
  • Change to a stiffer (or softer) rear axle
  • Add or tighten 4th rail
  • Add seat stays
  • Raise and or move seat back
  • Use a stiffer seat
  • Reduce (or increase) width of rear track
Reduce jacking effect
  • Increase width of rear track
Reduce front grip
  • Remove or loosen front torsion bar
Driving
  •  Turn later into corner 


 

Understeering out of the corner

Increase front grip
  • Add or tighten front torsion bar and crash bar
  • Move the seat forward
  • Use a softer seat

Driving

  • Reduce acceleration out of corner

 

Understeering all the way through the turn

  • Increase rear track width
  • Turn rear torsion bar to horizontal position or remove it
  • Loosen 4th rail
  • Increase front tyre pressure by 1 PSI


 

Bounce in the rear (too much)

  • Increase rear track width
  • Lower chassis height
  • lower seat height

 

 

Too little grip in all four tyres or there is not enough side bite

  • Decrease front and rear track width
  • Add or tighten 4th rail (normally should be tight)
  • Loosen the side pods
  • Raise the air pressure in all 4 tires by 1 psi
  • Raise (increase outside tyre bite) or lower (if outside tyres not able to cope with friction) centre of gravity
Driving
  •  Reduce steering movements


 

Too much grip in all four tyres (two wheeling around corners)

  • Increase width of front and rear track
  • Remove or loosen 4th rail
  • Lower the rear of the chassis (normally in highest position)
  • Tighten the side pods
  • Lower the air pressure in all 4 tires by 1 psi
  • Lower (decrease outside tyre bite) or increase (outside tyres not able to handle increased friction) centre of gravity

 

 

Lack of top end speed

Power related
  • Engine refresh (every eight hours)
  • Change sprocket
  • Change exhaust flex length
  • Change jetting settings
  • Change spark plug if fouled or select appropriate heat range
  • Check or replace fuel filter(s)
Friction
  • Check that brake pads are not touching brake disks
  • Check that front the wheel bearings are free spinning (should be able to turn with fingers)
  • Too much toe-in or toe-out
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