It’s common for auto racing vehicles to have a differential that controls the power transmission to the rear wheels, by allowing them to turn at different speeds when cornering. However, this is not the case for go-karts, as they don’t have a differential.
Go-karts don’t have differentials, because they increase the overall weight and center of gravity of the go-kart, require more maintenance, but most importantly because having differentials go against the technical regulations of the CIK-FIA.
This article will give you an in-depth analysis of why go-karts are not equipped with differentials and also how go-karts compensate for a lack of this additional gear train. Let’s take a closer look!
1. Differentials Go Against FIA Regulations
According to The Commission Internationale de Karting (CIK), go-karts are open-wheeled and open top motorized vehicles that are designed for motor racing. An important characteristic of go-karts is that they are typically stripped of all non-essential components to make them lighter and faster.
In light of this, the CIK-FIA also publishes technical karting regulations which clearly indicate that go-karts must not have a differential. The technical regulations state under Article 1, section 2.8, that go-karts must always transmit power to the rear wheels, whereby any differential (in any type of configuration) is prohibited.
“…any type of differential, whether through the axle, the wheel mounting hub or by any other means, is prohibited.”Article 1, section 2.8 – Technical Regulations.
This is the main reason why go-karts don’t have a differential. So long these rules apply, the transmission delivers power directly to the rear live axle. To compensate for a lack of controlling individual tire rotation speeds, go-karts use jacking and a flexible frame to get around corners effectively. More on this later!
2. Differentials Increase a Go-Kart’s Weight
Another reason why go-karts don’t have differentials is because this additional component would increase its overall weight. Go-karts are designed to be lightweight racing vehicles and are also stripped of almost all non-essential parts.
Mounting a differential to a go-kart would increase its total weight by about 30 – 40 pounds. Given that an average racing go-kart weighs only about 180 pounds, it means that a differential would add about 20% more weight.
This additional weight would also decrease its acceleration potential, which go-karts rely on to get around and out of corners swiftly. There are also other ways that go-karts can make up for this, mainly through jacking.
3. Differentials Increase the Center of Gravity of a Go-Kart
Differentials are typically located towards the back of the vehicle, in between both wheels of the rear axle. As go-karts have a live axle instead, a differential would require them to have a higher ground clearance so that it doesn’t make contact with the track surface.
To ensure that racing go-karts are as low to the ground as possible, they have a live axle with no differential. A low center of gravity allows go-karts to navigate quickly around corners without increasing the risk of flipping over. This is similar to the reason why go-karts have small wheels.
4. Differentials Require Additional Maintenance
Every moving part on a go-kart requires some form of maintenance. Differentials are a set of gears, also referred to as a gear train, that need constant lubrication to work effectively.
Having this in place would increase the maintenance required, through inspections and additional oiling of gears. While this may not be the primary reason for go-karts not having a differential, it’s one reason nevertheless.
How Do Go-Karts Compensate For Not Having a Differential?
It’s apparent that a differential provides vehicles with various benefits. Having the ability to control the individual speed of tire rotation has two main benefits. Firstly, it allows for increased grip around corners by reducing the amount of tire slippage. And secondly, it reduces tire wear as the wheels are rotating according to their distance traveled.
As go-karts don’t have differentials, they need to compensate to ensure they handle corners efficiently. There are two ways that help go-karts turn corners without sacrificing grip and tire wear. They achieve this by jacking, which is enabled through their flexible frames.
Jacking or lifting is a phenomenon in kart racing whereby the inner rear wheel lifts off the ground, in order to apply more pressure on the outer tires. This enables an increased grip to the outer tires and negates the inner rear tire from slipping around the track corner.
This is enabled through the caster angle, when turning the steering wheel into the corner. Additionally, this is also supported through a flexible and tubular frame.
Go-kart frames are typically made of AISI 4130 (chromoly), which is a low-alloy steel. This frame is tubular giving it an adequate amount of flex, particularly around its waist. This flex allows your go-kart to jack more effectively around corners.
As you can see, there is no need for go-karts to have differentials, as they are perfectly capable of applying the required amount of force on the outer tires to minimize tire slippage and increase grip around corners.
Racing go-karts will always have a transmission that transfers power directly to the rear axle that facilitates equal rear tire rotation, as stipulated by the CIK-FIA. Therefore, as long this ruling stands in the technical regulations, go-karts won’t have a differential – and they also shouldn’t need to anyway!