Kyosho IF55 7.8mm Taper Ball 2pcs

A pair of 7.8mm taper pivot balls for Kyosho's Inferno platform.

These are the balls that a linkage ball end snaps onto, used at suspension and steering pivot points across the car. The taper sets the standoff between the ball and the part it threads into, which makes the ball a geometry component rather than just a fastener: where it sits determines the link's pivot point and therefore how the suspension behaves through its travel.

They are genuine wear items. A pivot ball carries substantial load through a very small contact patch, and over time the surface galls and flat-spots. Once that happens the ball end cannot grip it evenly, the joint develops play, and that play shows up at the wheel as camber and toe that shift under load. A car with worn pivot balls will not repeat a setup from one run to the next.

At 7.8mm this is the larger of Kyosho's two common taper ball sizes, used at the higher-load positions; the 6.8mm is a separate part number. Two are supplied. Kyosho lists fitment across the Inferno MP-7.5, MP777, MP9e, ST-R, Inferno GT and GT2, and Inferno NEO.