One Lap with MM: Watts Link Myth Busted by Tire Sidewall Flex

MM’s exclusive undercar video debunks the notion that a Watts Link is better than a Panhard Bar for late-model Mustangs. In the hard cornering situations shown in this video, an MM Panhard Bar on a Fox/SN95 Mustang causes only 0.079” of lateral axle movement relative to the chassis. While that’s more than a Watts Link allows, it’s an order of magnitude less than the movement caused by tire sidewall flex: a whopping 1.75” in this test.

This video shows the tire tread planted firmly on the ground at all times. During cornering, the sideways loading moves the chassis, the axle assembly (because the Panhard Bar connects the two), and the wheel toward the outside of the corner. The tire sidewall flexes uncontrollably when the wheel loads up, allowing significant sideways movement of the wheel/axle/chassis. This lateral shift is many times the movement caused by the Panhard Bar’s arc, and completely overshadows it in terms of functional effect.

In this video the tire sidewall deflection can be seen moving the wheel/axle/chassis as much as 1.75”. At the greatest amount of suspension travel seen in this test (2.5”), there was still only 0.079” of movement from the Panhard Bar arc, which is irrelevant compared to the 1.75” movement caused by sidewall flex.

Fast racers know that a lower roll center provides more cornering grip than does a higher roll center. Since the Maximum Motorsports Panhard Bar provides a lower roll center than any Watts Link available for a late-model Ford Mustang, the Panhard Bar is the winner when it comes to lateral axle location and improved handling for a solid-axle 1979-2004 Mustang. For the 2005-14 S197 Mustang, our undercar video clearly shows no advantage by swapping from a Panhard Bar to a Watts Link--especially since the stock Panhard Bar provides that critical low roll center. The Panhard bar is also much less expensive and easier to install.

Conclusion: Myth busted by actual data gathered from real-world testing.

See the MM website for a fuller explanation of this subject.