Throughout the last 30 years spindles for Sprint Cup cars have undergone very little change from a design standpoint.

Even today the spindle most widely used is a facsimile of an OEM streetcar component that Detroit produced in the early 1960's.

Probably the most significant change in the lifespan of this design was the mid to late 1980's trend of converting the stock cars over from rear steer to front steer.

This meant moving the steering arm axis from behind the vertical upper and lower ball joint centerline to a position in front of the upper and lower ball joint centerline. In the earliest versions, even this change did not create a large paradigm shift in design or manufacture.

Since it is a two piece assembly, with the lower ball joint mount contained on the "steering arm", and the upright or "upper" section conveniently symmetrical in the suspension side view, most early conversions were simply accomplished by moving the right side part to the left position on the car, and vice versa. This was seen as a more stable, easier to install and maintain system for all involved. It allowed for better packaging of the center link so that the engines could be lowered further, and got the steering box out of the way of the left side of the engine, creating more clearance for exhause headers and the like.

Since then the basic geometry of the spindle has remained virtually unchanged.