Most off-road and racing go-karts use a transmission, unless they have a direct drive configuration. A transmission provides controlled mechanical power from the engine to the rear axle of the go-kart. You’ll most likely come across go-karts that use a torque converter or a clutch, as a transmission.

Torque converters are great for lower end torque, as they have the ability to adjust the gear ratio depending on the engine’s RPM. This makes it ideal for heavier or off-road go-karts. On the other hand, a regular clutch maintains the same gear ratio all the time. This makes it more suitable for lightweight or racing go-karts that are tuned for maximum speed.

In the later parts on this article, we’ll go through a full analysis on how torque converters and clutches operate and how they are different. As a quick guide, you may refer to the summary below.

Comparison: Go-Kart Torque Converter vs Clutch

A torque converter has the same function as a clutch. They’re both different types of go-kart transmissions, but they each have their own distinctive advantages. Before we explore them further, let’s take a look at how both transmissions work on a go-kart.

What Does a Go-Kart Torque Converter Do?

Torque converters are one of the two popular transmissions found on go-karts. A torque converter is a mechanical device that is attached to the side of the engine. As you can see in the image above, it runs on a two-pulley system. The smaller pulley, called the driver pulley, is attached to the engine’s crankshaft. The larger pulley is referred to as the driven pulley.

The driver pulley is connected to the driven pulley via a drive belt. On traditional setups, the crankshaft is directly connected to the rear axle via a sprocket and a chain. However, on a torque converter setup, there is a jackshaft that connects the driven pulley to the rear axle via sprockets and chains.

When idling, torque converters are fully disengaged. This means that even though the engine has started, the go-kart doesn’t move. Once the engine reaches an RPM of about 1,500+ the driver pulley starts to clamp on the belt, which in turn engages the driven pulley. The rotational force is subsequently applied to the jackshaft and rear axle, giving your go-kart motion.

What is interesting here is that as the driver pulley starts clamping on the belt, it decreases the gear ratio. Typically, the gear ratio will start above 2:1 and the higher the RPM the lower it will decrease the ratio to below 1:1. With regards to costs, torque converters are relatively affordable. However they’re a little more expensive than clutches, as they contain more parts.

What Does a Go-Kart Clutch Do?

On the other hand, a go-kart clutch is a non-variable transmission. This means that it has a fixed gear ratio, which is set by the crankshaft sprocket and rear axle sprocket sizes. The gear ratio remains the same across all RPM ranges of the engine.

There are many types of clutches that are used on go-karts, however the most common are dry centrifugal clutches. A centrifugal clutch consists of 4 essential components. An outer drum, which can be seen in the image above, encases the interior components. The drive sprocket is attached to the drum, and connects to the rear axle via a roller chain.

In the interior, you’ll find the friction material, which is held together by an arrestor spring. The internal components do not make contact with the drum, as the arrestor springs hold them together. The entire clutch is mounted on the crankshaft and turns, as the crankshaft spins.

At about 1,400 to 1,600 RPM enough force is exerted onto the spring that the friction material slowly starts to move outward, due to the centrifugal force. As the force is still not enough to make contact with the drum, the clutch is still “slipping”. This is not ideal, as it creates heat and wear on the components, while the kart isn’t really moving. Only at about 1,800 RPM enough force is applied and the friction material presses against the drum and the clutch is fully engaged, spinning the driver sprocket and the rear axle.

Differences: Go-Kart Torque Converter vs Clutch

The way a torque converter operates compared to a clutch is very different. The main difference is that torque converters idle before they engage and they start to engage at around 1,700 RPM. Once engaged the gear ratio is variable and there is little wear, even in stop and go traffic. The same can’t be said for clutches.

While clutches engage earlier, they have a slip range at about 1,400 to 1,600 RPM. Slipping can cause increased heat and wear on the parts. However, once a clutch is fully engaged, it feels much snappier.

This makes clutches more ideal for situations where you’re constantly engaging in higher speeds on the upper torque range. Torque converters on the other hand handle low torque ranges better, due to the variable gear ratio and the ability to easily disengage at lower RPMs.

Summary

• Torque Converters engage at around 1,700 RPM without slipping
• Clutches slip between around 1,400 to 1,600 RPM and fully engage at 1,800 RPM
• Torque converters are slightly more expensive
• Clutches can burn out if it slips too much or too often
• Torque converters work best for low to mid torque ranges
• Clutches work better for mid to high torque ranges

Is a Go-Kart Torque Converter or Clutch Better?

What’s better, a torque converter or a clutch? The answer really depends on its intended use, which is ultimately related to your driving habit. As torque converters handle low torque ranges more easily, they’re most commonly used on off-road go-karts. They perform better at lower speeds and are ideal for stop-and-go situations. This is because off-road go-karts are sometimes required to climb uneven terrain at lower speeds.

Clutches on the other hand are snappier and perform better at high speeds. They’re designed to be constantly engaged, which makes them ideal for racing go-karts. High performance go-karts even have a multi-disc clutch to cater for various torque ranges. So, if you’re comparing a go-kart torque converter vs a clutch, you should make a choice depending on what you’re using it for.