- How do I adjust my Go Kart Caster Angle?
- Why Do I need to adjust Caster on my Go-Kart?
- When should I adjust Caster?
Caster is a front-end geometry adjustment that will have a direct effect on steering effort, steering effectiveness, and overall go kart speed.
Go Kart Caster Angle. What is Caster angle on a go kart? Why does a go kart need caster angle? How and why should I adjust caster angle?
All valid questions!
How do I adjust my Go Kart Caster Angle?
Adjusting caster on your go kart is as simple as leaning the kingpin bolt toward the driver’s seat or away from the driver’s seat… Simple right.
Leaning the kingpin bolt toward the rear of the go kart creates Positive Caster
Leaning the Kingpin bolt toward the front of the go kart creates Negative Caster.
Go Karts in the old days could not adjust caster so easily. The angle of the kingpin bolt was determined when the yoke was welded onto the frame!
Not much adjusting that! Unless you of course cut the yoke off the frame and start fresh.
Today, racing go karts have multiple ways that the angle of the kingpin can be adjusted. In the end they all accomplish the same adjustment.
Pictured is a Kingpin bolt. As you can see the yoke is welded to the frame. Additionally, the bolt does not have an eccentric adjustment, slide, or adjustable Heim joints. Therefore, caster cannot be adjusted.
In the Video you will see an eccentric bolt adjustment. The yoke is still welded but the caster adjustment is made at the eccentric.
When someone refers to the “yoke” on a go kart they are speaking about the area between the arrows.
Why Do I need to adjust Caster on my Go-Kart?
Positive Caster – You need the front wheels to do more mechanical work.
Negative Caster – You want the front wheels to do less mechanical work.
Positive caster angle will create more grip in the front tires.
Positive caster also keeps the front wheel straight. Increasing in a positive caster angle will increase the speed in which the front wheels return to the straight position.
Increased Front Grip
For example, if we turn left in our go kart the LF tire will push into the ground based off the rotational plane (king pin bolt) in which the spindle in mounted.
If the caster angle was 0 degrees, the spindle would not move up or down when rotated. The spindle would rotate on a flat plane.
With the bolt leaned rearward, when turning left the rotation becomes a downward motion.
When turning right the tire will rotate on an upward plane.
When should I adjust Caster?
A Caster adjustment is not going to be the same adjustment for every go kart driver and go kart. What is important to know is how your go kart should react when caster is adjusted. This is something that will take time and practice.
Feel – One of the first feelings a driver will notice is the feel of the steering wheel while turning. A go kart with more caster will have a stiffer or harder to turn steering wheel. Conversely the opposite if caster is reduced.
This is due to the forces of pushing the wheels into the ground as you turn the wheel. As the inside front tire rotates downward your are lifting the gokart frame.
Including the driver, a go kart can weigh close to 400 lbs.! And you are lifting some of that weight just by turning the wheel.
The feel is important to the driver. The driver is the one out there making moves. If the driver is uncomfortable, they will make it known.
Weight Jacking – Weight jacking is a huge factor when adjusting caster. Like mentioned earlier if positive caster is present the inside wheel will travel down into the track. Due to the axis of rotation the tire is forced down into the track.
When the inside front wheel is forced down it raises, the rear wheel on the same side. This assists in the transfer of weight helping the rear wheels release from the track.
Camber Gain – Caster angle when increased or decreased will affect camber gain. Camber gain is the amount of camber gained or lost during steering wheel input.
For a quick test put you go kart on the ground or floor and install your caster camber gauge. Turn the wheel and watch the camber increase or decrease.
A in depth explanation of camber gain can be found in The Dynamics of Speed – Todd Godwin
As you can see there are multiple reasons as to when we should adjust camber. Every go kart and go kart driver will react differently to a caster change.
Go Kart Caster Camber Gauge
When setting up caster you will need the proper tooling.
Setting caster can be tricky to measure it true.
Go kart manufactures will indicate the caster angle by lines or grooves on the frame by the king pin bolt.
If you trust your chassis manufacturer than this should not be a problem. One of the truest ways to check caster is to fix a digital level to the king pin bolt. Or to an area that is parallel with the king pin bolt.
This will tell you exactly what your caster angle is.
Go Kart Racing Caster Angle
Caster angle is the angle in which the kingpin bolt is leaned, forward or rearward.
The angle… of this article is to try and help new racers be Better Karters.
Try adjusting caster angle the next time you’re at the track. See how your go kart reacts. Trial and error are sometimes the best way to learn!
Remember there is not one special adjustment that is perfect for everyone. Find what works for you and make small adjustments from there.
Check out BetterKarting for some more awesome go karting tips and tricks.