Part 1
6/7/04

Inside today’s drag cars, you’ll find all sorts of rod ends or spherical bearings. Rod ends, or as the Brits sometimes call them, “rose joints,” happen to be one group of components that get little or no respect. They all look the same (sort of), and when they’re buried deep inside of a car, they’re out of sight and out of mind. However, rod ends may be one of the most critical hardware pieces on your drag car. And yes, they see use in places other than the suspension. For example, rod ends are used in the carburetor linkage. Because they’re not a high profile component, they’re very easy to forget about. Until they break.

When a rod end breaks, things can get ugly. Fast. You see, most rod ends are regularly used in places where they’re charged with handling considerable loads. Rod ends are more than important. They’re critical. And there’s something even more acute: Not all rod ends have been created equal. Some are true aerospace quality. Others are nothing more than junk. Where it becomes really confusing is when you look at a rod end. It’s difficult to tell the difference between an extreme quality rod end and one that just fell off the boat from some sweat shop in the Eastern hemisphere.

When shopping for rod ends for a racecar, look for models like this. They’re a three-piece precision design. In rod ends with this construction format, the race is formed around the ball and then the race insert is staked into the body. This type of construction offers a much closer fit along with a much higher degree of precision between the ball and the race. Because of the three-piece design, different materials can be embodied during construction. This process allows the rod end to best match the application (i.e.: strength versus loads).

The Rudiments Of Rod Ends

By design, a rod end basically consists of a spherical ball that is designed to rotate inside a housing. This ball is the bearing and the housing it’s contained in is the race. The spherical ball is machined flat on each side, and this modified “sphere” is bored with a hole through the center.

There’s something you really can’t see here. Rod ends are usually available with left or right hand threads. That means that for an application such as a trailing link, you simply order the appropriate bearing (be careful—some of the part numbers listed in rod end catalogs are at the best, confusing when it comes to thread types). There’s another thing to consider: Be careful when purchasing jam nuts. They’re not all created equal either. Quite frankly, the A-N or aircraft hardware industry is plagued with inferior knock-off components. And like inferior rod ends, some of this stuff is absolute junk.