Chain Drive Differential

A chain drive differential is a component of a chain drive system used to deliver power to the rear axle of a vehicle.

Once common on a wide range of vehicles, chain drives and chain drive differentials are now used mostly on certain racing cars, mainly racing karts, Formula Student (FSAE) cars, and even some sports cars.

Here’s everything you need to know about chain drive differentials. 

What is a Chain Drive Differential?

A chain drive differential is a gear train with three shafts paired with a chain drive power transmission system to supply power to the rear wheels of a vehicle. 

The key benefit is the ability of each tire to rotate on its own. For example, the outer tire can rotate faster on turns than the inside tire to prevent skidding, slipping, or drifting. 

The inner workings of a chain drive differential (particularly the three shafts) enable a proper balance in the speed of the two tires. When the speed of one tire increases, the speed of the other tire decreases. 

Because of their advantages in racing applications, chain drive differentials are popular on a wide range of racing and other vehicles that require precise maneuverability at high speeds.

It’s possible to install a chain drive differential in a vehicle built from scratch or to include one in the conversion of many old vehicles.  

How Does a Chain Drive Differential Work?

A chain drive differential works much like a standard automotive differential. Think of a chain drive differential go kart. 

In fact, there are limited differences in the function and application between the two, aside from the lack of a driveshaft in a chain drive differential. 

The exact way a chain drive differential works depends on the type. Open differentials, limited-slip differentials, and automatic torque biasing differentials are the main types, although several other, less popular types are available. 

All of these chain drive differentials work in much the same way. The motor supplies power to the differential through a gear or sprocket. It then goes to the wheels via the differential. The three-shaft design enables the wheels to rotate at different speeds without overwhelming the system.

The most basic chain drive differentials are great for on-road use, although a specific type, usually a limited-slip differential, is required for most off-road applications. 

Benefits of a Chain Drive Differential 

As stated above, the main benefit of a chain drive differential is the ability for both rear wheels to rotate at different speeds without reducing power.

A chain drive differential is also great for maintaining power over uneven terrain. Because a chain drive system allows for greater vertical axle movement, these differentials are often used on off-road vehicles, such as dune buggies.

First and foremost, a chain drive differential provides highly efficient power. But these systems are also easier and cheaper to maintain. They’re relatively easy to make, install, repair, and replace on your own with basic mechanical knowledge and simple tools.

DIY Chain Drive Differential 

Are you interested in installing a chain drive differential in your vehicle?

Luckily, making this a DIY project isn’t extraordinarily difficult for mechanically minded individuals with a few simple tools. 

A chain drive differential can even be purchased online. Several manufacturers sell them. From there, it’s as simple as installing on your vehicle of choice.

That said, it’s also possible to make a chain drive differential for scratch. Such a project is best suited for hobby vehicles like go-karts and dune buggies, however. 

This video by What’s Going On In Doug’s Shed and this video by Homemade Madness break down the process of building a simple DIY chain drive differential from scratch. 

Chain Drive Differential for Go-Karts

Go-karts are among the most common recipients of chain drive differentials.

The best chain drive differentials for go-karts are highly power-efficient. They supply power directly from the chain drive to the rear tires with great efficiency. 

These differentials are so popular for karts of all types, both on-road and off-road models, because of their ability to allow both wheels to rotate at different speeds. This is essential for keeping traction at high speeds on corners. It also allows for more power over uneven terrain. 

This video from Gas Pedal Garage describes the benefits and how to build a chain drive differential for go-karts in more detail. 

Chain Drive vs. Belt Drive System

Both chain drive and belt drive systems use differentials to supply balanced power to the wheels. 

That said, each system has its pros and cons. Although chain drives are very effective at certain applications, there are many applications where belt drives have the upper hand.

Belt drives require very little maintenance compared to chain drives, which, in comparison, require regular tightening, cleaning, and maintenance. 

On the other hand, the maintenance required for chain drives is very cheap. They’re also far easier to replace and install than belt drives when the time comes.

Another advantage belt drives have over chain drives is a smoother ride. Chain drives tend to be jerkier than belt drives, which are known to operate very smoothly. 

Finally, chain drives provide much better power efficiency than belt drives. Although it depends on the exact setup, belt drives lose around 10% power while chain drives are around 99% power efficient. 

Because both of these drive systems have their pros and cons, the right choice for you depends on the type of vehicle you have as well as your planned application.

Final Thoughts 

A chain drive differential has many applications for a range of different vehicles. They are notable for their minimal maintenance, ease of installation, and high power efficiency. A few models are commercially available, although installing a chain drive differential is a popular DIY project.