Flange Yoke Showdown

Sonnax Flange Yokes vs. Spicer Flange Yokes

Racers and technicians are always on the lookout for stronger, lighter parts to install that will give a performance advantage or upgrade. Often, comparing competing parts can be difficult due to a lack of concrete testing evidence to consult, and limited availability of appropriate product information. This is especially true of seemingly “simple” hard parts such as flange yokes. Recent comparison testing of a Sonnax (aluminum) 1859 flange yoke versus a Spicer (steel) 1859 flange yoke provides valuable insight into some key differences between the two.

Sonnax 1859	Spicer 1859

The yokes were tested at the Sonnax technical center in Vermont using a torsional test machine (Figure 1). Precise torque levels were applied and measured with a torque load transducer (Figure 2). Applied torque was incrementally increased in an attempt to find each yoke’s ultimate failing point.

Figure 1	Figure 2

Test results reveal that the Spicer flange yoke and the Sonnax flange yoke fail at identical maximum torque loads, which demonstrates that the strength-to-yield of these yokes is equal. However, though they have corresponding durability, the yokes display quite different modes of terminal failure.

When the Sonnax yoke reached the failure torque load, its aluminum construction plastically yielded, stretching the U-joint bores into ovals but holding on to the driveshaft (Figure 3).

Figure 3

In contrast, when the Spicer yoke failed it did so catastrophically, shattering like glass and disconnecting from the driveshaft (Figure 4).

Figure 4