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MM Coronavirus Update

We’re changing our phone hours to 9:00 AM to 3:00 PM Pacific Time (Monday-Friday, excluding holidays) so we have more time to process orders and get them out to you.

Please be aware
Our supply chain is suffering major pandemic-related disruptions. Many of our suppliers shut down for a time, and like us are operating with reduced manpower. Meanwhile, demand for MM products has skyrocketed. Thank you! We’re a small company and we regret our website isn’t fancy enough to inform you of back orders when you buy something. Please understand that we’re working as fast as we can to fill your orders.

UPS Shipping Times As of March 24, UPS no longer guarantees the shipping time for any shipment. i.e., expect shipping time to lengthen.

Mustang Rear Lower Control Arm FAQs

Why change from the stock Mustang rear lower control arms?
Because the stock lower control arms were designed for a grocery-getter, not a performance car. One of Ford's main goals when they designed the rear suspension was to avoid complaints about NVH (Noise, Vibration, Harshness) from little old ladies. As performance enthusiasts, we have very different goals.

What do the rear lower control arms do?
Rear lower control arms, along with the upper arms, control axle rotation.

All of the forces that accelerate the car pass through the rear lower control arms: The tires rotate on the pavement, moving the axle forward. The axle pushes on the rear lower control arms, moving the rest of the car forward. The control arms, and their bushings, must withstand those forces.

What's wrong with the stock control arms?
In stock form, the rubber bushings in the control arms allow excessive deflection that prevents the rear axle from maintaining its correct position under the chassis. The axle is allowed to shift forwards, backwards, and sideways under the car. This is the primary cause of wheel hop, and leads to poor traction and poor handling.

The stock arms are made of stamped steel. That style of construction is very cheap for mass production, but it does not make for a rigid control arm. Deflection of the steel arm contributes to wheel hop.

Instead of improving the control arms, Ford's attempted solution to stop wheel hop was to add the quad shocks (the two horizontal shocks mounted behind the rear axle). These shocks damp out oscillation and reduce the axle rotation allowed by deflection of the rubber bushings. That rotation (axle wind-up) leads to wheel hop.

More Tech

Tech about MM rear lower control arms

Specific tech about the MM Heavy Duty control arm series.

Specific tech about the MM Extreme Duty control arm series.

Specific tech about the MM Road Race control arm series.