Learn More About Differentials!

A differential, or as it is commonly referred to as, a “diff“, is an aptly named assembly that exists to allow the driven wheels at each end of an axle to rotate at different speeds. This helps (and depending on the type of diff and the circumstances, hinders) in controlling the traction available to the model car as it attempts to divide the torque equally between the two wheels.

After watching the video above, I think you should have some basic understanding on how differential steering works! So now, let me introduces few different kinds of differentials!

Basic parts of differential:


Gear Differential:

Gear differential are comprised of a series of gears that transfer power from the input shaft to the wheels. Gear diffs are inexpensive to produce and can be quite durable, so you will find them in lots of RTR or Monster Truck vehicles. Gear diffs are also not externally adjustable. Adjusting a gear diff means removal from the vehicle and adding different viscosities of fluid to limit slip.

Example of Gear Differential:

xray_xr-304900_2   xray_xr-304900_1

Ball Differential:

Balls differential are more of an upgrade, or competition style diff. They use small balls and rings to limit slip. The more you tighten down the ball diff, the more pressure it takes to slip. Ball diffs do require a bit more maintenance, but can be externally adjusted to help the performance of your vehicle.

Example of Gear Differential:


3racing-SAK-D4833-1  mst-210352r-1


One Way Differential:

The One Way Differential simply removes diff action from the front of the car. You will no longer have a ball style differential in the front of your car. Instead, the ‘OneWay housing’ uses two (sometimes four) ‘OneWay’ roller bearings that spin in one direction. Once your input shafts have been installed, the roller bearings will only allow them to spin in one direction.

Example of One Way Differential:


Solid Axle:

On a solid axle truck, the differential, driveshafts, and hubs are all contained in an axle housing that reaches from wheel to wheel. Links are used to attach the axle to the chassis and allow the axle to move up and down as well as twist to deal with bumps and varied terrain. Typically there are four links, and at least two of the links are triangulated to keep the axle centered beneath the chassis. Since the hubs are fixed to the truck’s axle, you can’t adjust camber so the tires are set at zero degrees.

A solid-axle system offers a few advantages. First and foremost, a solid-axle offers greater ground clearance and terrain-crawling ability. As one wheel lifts over an obstacle, the entire axle lifts with it. A solid axle also allows for sharper approach angles on obstacles than an independent-suspension design. The downside of a solid-axle is high-speed handling. Since there’s a lot more mass for the shocks to control, and each bump is transmitted to the entire axle, a solid-axle truck will not be as stable when going through rough terrain at speed as an independent-suspension design.

Example of Solid Axle:

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Best Setup? 

In order to achieve the best setup for your application, it will take some trial and error in order to match your cars performance with your driving preferences. If you already have an idea for this, it will be easier to achieve the best setup more quickly. In general all choices will be a trade off. You will select a specific weight of oil in order to gain a performance characteristic, however you are always going to be sacrificing something.

Also, it is important to consider that higher weighted oils will generally be more difficult to handle. It may provide excellent acceleration performance, but with a higher power setup and tight turns, experience and skills will be needed to keep it all under control with throttle, brake and steering management.