2009 Mustang GT - Stock rear suspension in action on the streets

This video was shot to show how the stock 2009 Ford Mustang GT live rear axle suspension working while on the streets. Ultimately the goal was to do a voice over with information pertaining to live rear axle suspension geometry, but I decided that listening to some guy babble on and on is just as boring and possibly more confusing.

The stock rear suspension in the 05+ Mustangs is what is called the 3 link rear suspension. It has one upper control arm, two lower control arms, and a pan hard bar. For those counting, that's 4 actual linkages, but the 3-link refers to longitudinal (front/rear) locating devices, which is ONLY the upper control arm and lower control arms.

The panhard bar geometry is superior to the previous generation fox body and SN95 chassis 4 link system in which there where two upper control arms that where mounted such that the axle side was more to the center of the axle than the body side and 2 parallel lower control arms. The Fox Body/SN95 4 link is affectionately called the "quadra-bind" because under cornering loads there is considerable axle bind which can cause loss of traction and severe oversteer conditions mid corner.

Ford addressed this issue in the S197 platform by going to the 3 link + PHB arrangement. The upper control arm and lower control arms work together to perform the fore/aft axle location, while the panhard bar (PHB) laterally locates the rear axle. The control arms also server the dual purpose of holding the pinion angle constant, something it does better than the quadra-bind system but doesn't do it flawlessly (to fix this problem requires a Torque Arm).

The PHB configuration is not without it's own flaws. The PHB's motion inscribes an arc, which can cause the rear axle to feel unsettled in extreme cornering or over bumps. The PHB also changes the roll center of the axle in a diagonal which can cause the car to turn easier in one direction and not the other. The ultimate fix for the live rear axle will always be the Watts linkage which has no turning bias and only has side to side movement at EXTREME suspension travel which allows the rest of the suspension to do it's job better by not flexing side to side during suspension travel.

Category:

Autos & Vehicles

Tags:

• 3linkLRAinaction

[UrPeaceKeeper]

For a live axle set up, the 3 link + PHB is pretty solid, its biggest weak link is the PHBs asymmetric behavior in cornering. In the case of 05+ Mustangs it favors right hand corners (PHB plants left wheel in right hand corners and "lifts" it in left hand corners). The quickest fix is for a Watts link which is symmetric for handling purposes and doesn't favor one direction over the other.

[PeteSwitch]

Awesome, now I have a basis to go off of for the missing components of my lowered S197. Thanks for posting this up!

[UrPeaceKeeper]

@PeteSwitch What components are you "missing" ???? Ideally the S197 (05+ Mustangs) needs a new adjustable Panhard rod (or Watts link) to center the rear axle properly and adjustable Upper Control Arm (and most likely the mount too) to control pinion angle changes, and a set of relocation brackets to drop the lower control arms on the axle side back to level or just below level to get the traction on launch and proper roll steer back to factory specs. Suspension is a system so it all has to go.

[LaCrimsonLey]

Seems like a good system but then again I'm a noob when it comes to suspension.

[xilix]

@UrPeaceKeeper And this is why I hate seeing people lower their own car if they don't know what they're doing. It so unsafe it's not even funny. There are SO many cars around my area that have improperly lowered suspensions, it's ridiculous. You can see them pulling all over the place over the slightest little camber in the road. I just shake my head, switch lanes and get away from them.

[p4ndiamond]

this is sweet even tho im sn95