Racing Rearend Build - Building The Ultimate Rearend, Part 2

With the axles in place, the drive flanges are ready to be installed. But first we thought we’d show you a shot of the underside of these billet flanges before they are bolted up. Notice the O-ring which should seal the flange so that no messy silicone is necessary. Often, it’s the little details like this that will make you life as a racer much easier.

Bolt the drive flanges up. With the flange cover off it’s possible to easily and quickly remove the axles for inspection if necessary.

The Joe’s Racing billet aluminum flange covers not only look nice, but they shouldn’t get bent up and start leaking from after a couple of races.

Before sliding the rearend underneath his race car, Hargett takes a moment to bolt up the brackets for the torque arm.

Now we’re ready to begin the process of hanging the rearend underneath the car. This chassis uses a four-bar setup, and the suspension arms bolt to the birdcages with Heim joints.

Harget showed us this trick to keep the Heim joints rotating smoothly. He uses a grinder to roll back the underside of the head of the bolt (right) so that it can’t catch and hang on the shoulder of the Heim joint like a stock bolt (left) potentially can.

In addition to the other components we’re using from Joe’s Racing, we’ve also chosen this billet aluminum J-bar. Keeping all unspring suspension components as light as possible is critical to making the car’s handling as responsive as possible, and the billet aluminum design accomplishes that while also being quite strong and capable of handling abuse.

Here, you can see the J-bar being installed on the car. It works like a Panhard bar to locate the rearend laterally, and the curved design allows it to clear the driveshaft even with the extreme movements a dirt car rearend will make as the driver attacks the racetrack.

Joe’s Racing says it has customers that have found running lightweight gear oil in the hubs versus the more standard practice of packing it with grease can free up 6 to 8 horsepower. Joe’s recommends between 4 to 7 ounces of 85- or 90-weight gear oil. The easily removable seals make it easy to inspect your hubs weekly to get the maximum performance. You can’t see it in this photo, but each hub comes with an easy to reach fill hole. Just spin the hub until it is on top, pour in your gear oil and thread the plug back into place.

Your chassis builder can provide you with measurements for setting up the rearend in the car. Most will give you baseline lengths for all four suspension arms and another measurement to locate the rearend laterally underneath the car.

Finally, the fill tube is attached to the bell. Every gear change drains the rearend of much of the lubrication, and the fill tube allows to quick lube refills from outside the car.