Finding the best material for a go-kart frame or chassis can be challenging, as there are many different types of go-karts and also quite a large number of materials to choose from. If you want to read the short answer, the most common and best material for go-kart frames is steel. However, it’s not just any type of steel. In fact the type of steel depends on the type of go-kart.
There are also other types of materials that can be used for go-karts and in this article we will be exploring and understanding them in a little more detail. It’s important to identify the right material for the right type of go-kart. However, there are also several suitable materials that can be used for each go-kart type and each has certain advantages over the other. If you’re interested to understand the logic behind each of these materials, please read on.
Frames for Racing Go-Karts
As you know, racing go-karts are performance vehicles with the sole purpose of winning races. Therefore, it’s in their nature to be as lightweight as possible, in order to benefit from higher top speeds and quick acceleration. Go-karts also have a tendency to be equipped with heavier engines and components.
For those reasons the material used for a racing go-kart frame cannot be too heavy and too flimsy. That’s why professional go-karts have frames that are tubular in design. CIK-FIA homologation dictates that go-kart chassis must be made from ‘magnetic steel’ and the most common materials used are either AISI 4130 or AISI 1018 steel alloy. Let’s take a closer look at both of them.
|Cost Per Meter
AISI 4130 (chromoly) is a low-alloy steel that contains 1% chromium and 0.2% molybdenum, which act as strengthening agents. This steel alloy is known to be the best material for go-kart frames, due to its high yield strength, tensile strength and hardness. As go-kart frames are tubular, they need to ensure the high amounts of structural integrity throughout the entire frame.
The AISI 4130 steel has an unmatched yield strength of 460 MPa and a tensile strength of 560 MPa. Hardness and strength are also important on areas of the frame that are bent, to ensure that the frame stays in fact. However, it also needs to be noted that AISI 4130 is about 2 times more expensive than AISI 1018.
AISI 1018 is a medium low-carbon steel that is also used for building go-kart frames. It has similar properties like AISI 4130 but to a lesser degree. Having a tensile strength of 440 MPa and a yield strength of 317 MPa, it can easily be used in a tubular form to create a stable and robust go-kart frame.
Although it isn’t as strong and sturdy as AISI 4130 and is slightly heavier, it can provide great properties to ensure the structural integrity of a go-kart frame. However, this also means that the cross sections would be slightly thicker than AISI 4130. The main benefit of the AISI 1018 is that it’s less than half the price of AISI 4130.
Frames for Homemade Go-Karts
It can get a little tricky when it comes to homemade go-karts, as there many different types of go-karts and materials to choose from. Generally speaking, you would want to ensure that your custom go-kart has enough structural integrity to be safe, but you also don’t want to over-engineer it, as it may affect its overall weight and cause your go-kart to underperform.
There are three types of frame materials that you can consider for your homemade go-kart, which are steel, aluminium and wood. Steel and aluminium are mostly used, whereas wood is only recommended for mechanical go-karts or go-karts that are meant for kids.
|304 Stainless Steel
Of course you could go with AISI 4130 or AISI 1018 alloy steels, as they’re used for professional go-kart racing. This is the preferred material but it’s also relatively expensive and you may not even require such a material for your go-kart frame with that high of a tensile and yield strength. Instead, you could go for stainless steel. Stainless steels such as 304 have a good tensile strength and yield strength that are suitable go-kart frame materials.
Ideally, you should be going for round or rectangle tubular designs and use proper welding techniques to build your frame. Although 304 steel is heavier than AISI 4130 or AISI 1018, it is much cheaper and easier to weld. If you’re a hobby builder and are looking for a material for your go-kart frame with great properties for an affordable price, you should definitely consider 304 stainless steel.
The advantage of aluminium is that it is lighter in weight than stainless steel. This means that if you construct a light go-kart frame, the overall weight of your go-kart is reduced, meaning you can opt for a smaller engine with the same overall output. However, you’ll need to also consider the fact that aluminium is also not as strong as stainless steel having a tensile strength of 310 MPa, compared to 505 MPa.
Due to its higher thermal conductivity, aluminium also requires higher heat input in order to weld. Therefore aluminium is only recommended as a go-kart frame material if the kart you plan to build is not meant for heavy loads or high speeds. This also means that a tubular go-kart frame may not be suitable, unless the weight distribution and welding is on point. Consider this carefully and when in doubt, it’s best to use 304 stainless steel, instead.
Wooden go-karts are not very common for many reasons and wooden go-kart frames are only used in very specific applications. As you can see in the chart, wood has an average tensile strength of 2 MPa and a yield strength of 40 MPa. Compared to any form of steel, wood doesn’t seem to stand a chance. However, there are certain scenarios where wooden go-kart chassis make sense.
If you’re building an homemade pedal go-kart, a wooden frame can be suitable. If there are no extreme forces exerted on the frame and it’s mainly carrying the weight of the driver at low speeds, a wooden frame will be able to support it. A case can also be made for very low-powered electric go-karts that are either low-speed or that are meant for kids. For obvious reasons, it’s not recommended to install any standard sized go-kart engine or motor on a wooden-framed go-kart as it can break at higher speeds and upon colliding with an object.
The main benefits of using wood as a go-kart frame material is that you can easily construct it using planks, in combination with screws or bolts. Wood is also extremely light in weight, is very inexpensive and can be easily sourced. However, it’s biggest downside as a go-kart frame is it’s lack of durability and sturdiness compared to aluminium and stainless steel. Therefore, you should only consider this under certain circumstances.
Frames for Off-Road Go-Karts
Off-road go-karts require a strong frame, due to the fact that they are generally heavier and need to withstand a higher degree of impact. Therefore, the frame material should have a relatively high tensile and yield strength. It must not only be able to carry more than one person, but also the load of an increased engine size.
Most off-road go-karts use a steel frame due to its high yield strength, tensile strength and affordability. These types of go-kart chassis do not need to be built to CIK-FIA homologation, as they are not aimed towards competitive racing. Instead, these are hobby go-karts that are driven on off-road terrain.
Therefore, any type of steel alloy such as stainless steel is a suitable frame material for an off-road go-kart. Anything with a lower tensile and yield strength of steel will increase the risk of frame damage while riding. Due to this, aluminium is not recommended for off-road go-karts.
Off-road go-karts also require more material as they are bigger than racing go-karts and need to account for the additional weight of the increased engine and other parts. Using AISI 4130 or AISI 1018 steel will also work, however it will also increase the cost of the go-kart frame significantly. Therefore, 304 stainless steel is perfectly fine, unless you have a larger budget.