Kart Setup & Handling
Basic Recommendations for adjusting Kart Handling
“Understeer is when you hit the wall with the front of the car
and oversteer is when you hit the wall with the rear of the car.
Horsepower is how fast you hit the wall,
torque is how far you take the wall with you.”
|UNDERSTEER (PUSH) ALL THROUGH TURN|
1. Remove rear torsion bar
2. Increase castor in front spindles
3. Widen front track-narrow rear track
4. Loosen adjustable seat strut
5. Move seat forward
|UNDERSTEER ON TURN-IN|
1. Front track too narrow, widen track by adding 6 mm spacer to each spindle. Do this one spacer at a time.
2. Narrow rear track
3. Increase castor in front spindles
4. Raise rear of seat
|UNDERSTEER APEX OUT|
1. Raise rear ride height
2. Move seat forward 12 mm
|OVERSTEER ON TURN-IN|
1. Decrease castor in front spindles. Remove the castor pills and go to standard setting or remove 10 pill and replace with 6.5
2. Narrow front track by removing spacers from spindle
3. Widen rear track
4. If no torsion bar is installed, put in torsion bar with blade flat. If torsion bar is in and in flat position, then turn torsion bar to vertical
5. Tighten adjustable seat strut
|LACK OF TRACTION (LOOSE) OFF THE TURN|
1. Add rear torsion bar or if installed move to vertical position
2. Lower ride height
3. Widen rear track or narrow front track
4. Lower rear of seat
|REAR OF KART IS LOOSE ON TURN-IN|
1. See oversteer on turn-in
2. Increase rear width
|KART PREPARATION PRIOR TO DRIVING ON TRACK|
1. The placement of the seat will be the most important factor in how the kart behaves (handles) and responds to adjustments. Place the seat so the bottom is in line with the bottom of the frame rail. The back edge of the seat should be 10″ from the top of the rear axle, with the axle in the bottom position. All measurements are for Tillet seats. The right front edge of the seat should be 23.5″ from the back edge of the frame’s front tube. The left front edge of the seat should be 23″ from the back of the front tube.
2. Set the wheel alignment with any of the commonly available tools made for this job. The toe setting should be 1/16″ out. Now inflate the tires and make sure that the circumference of the tires matches right rear to left rear and right front to left front.
3. Once the seat is mounted and all systems (engine, pipe, chain, fluids, etc.) are installed you are then ready to proceed with checking the kart for proper weight distribution. Find a flat level area (cement or firm asphalt) and place four identical bathroom scales on the ground with each scale in position to be below each tire. Weigh yourself on each scale and adjust so every scale registers your weight equally. Now place the kart on the scales, put your helmet and driving shoes on and sit on the kart in your normal driving position, holding the steering wheel with your driving grip and point the wheels straight ahead. Have your girlfriend, or, if you are unlucky, your buddy, check each corner weight. No corner should differ more than 5lbs of its opposite side. If the corner weights don’t meet the 5lb rule, then you must move the seat or weights, if any are installed, until you get the corners within 5lbs. The next step is to check front to rear weight distribution.The beginning settings for weight distribution should be 42% front, 58% rear. Move seat or weights to get this setting, but when moving things around make sure that your left to right weights stay within 5lbs. Sounds like a lot of work, but it really is not and it will pay huge dividends in setting up the kart at the track. We used bathroom scales for our example because not everyone has the money to buy the electronic scales sold by a number of different companies. Trust us, if you follow our directions and the bathroom scales are not hammered, your weights should be OK.
4. On karts with adjustable wheelbase we recommend that you start with the wheelbase set at the center position. For tight short tracks the short wheelbase position may be better because the kart will have faster response to steering input. Long wheelbase is preferable in long sprint tracks with a preponderance of fast sweeping corners. Road racing normally is done with the wheelbase set in the long position.
5. Ride height adjustment determines the side bite of the kart, mostly at the rear wheels. Setting the kart with high ride height increases side bite. The opposite effect is achieved when the kart is set-up with low ride height.