S550 rear end movement

[Alloy]

When I feel the "wobble" I'm just on the highway doing normal HW speeds and change lanes to pass someone. The quicker I do it, the more wobble there is. I have had an alignment. I'll need to post up the results.

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[Rick B]

If that was my car I'd bring into a collision repair shop thats certified frame repair and have them check your undercarriage. This doesn't ring true. People that do alignments may not see an issue. You could also bring it to dealer other than one you bought it from.

 

[Mustang Mikes Queen Creek]

Yeah that's pretty much when it does it,any time then road changes its a side to side bobble head motion,Comming in and out of a turn the car is solid,It feels like the car is allways on a weak sidewall slick,just a bunch of ass wagging,super noticable when comming onto the freeway going down hill a bit.Is what it is,I'll just live it for now.Rear sub structure bushings sound like the way to go,I'd hate to add anymore weight to an allready heavy pig,other then that the car rides nicely.I have one low speed annoying rattle that I havent found yet comming from the driver's rear,and alot of exterior air noise hitting the drivers side window,Hoping Ford can reset the window and find my rattle.I didn't buy it to wrench on it to much aside from small no brainer Bolton's.Weekend cruiser car.

 

[Guard5.0]

I call it oscillation. Mine was bad stock. With more power and springs only (before coilovers) the car was really unsettling to drive even a little aggressively. It's taken some upgrades but car now handles in a predictable manner even when pushed hard. Coilovers really helped but all of these s550's need to have the rear cradle solidified. There's a reason it's called a "Grand Tourer" and not a sports car. The trade off is NVH increases.

 

[hulk_smash]

I'm on FRPP solid subframe/diff bushing, Cortex Spherical lower control arm F&R bushings, Full Tilt Boogie vertical links + upper control arm spherical bushings, FRPP toe to knuckle bearing and BMR sway bars/end links. The car has every single solid bushing available and it handles so well with stock PP shocks and Swift springs. No more lethargic feeling or midcorner understeer to snap over steer on exit.

Stiffen up the bushings and it is night and day. I had the BMR CB005 (a fantastic product in its own right) which helped immensely but not quite the solid feel I have now. But its a mod that gives you maybe 70% of being full solid, at a much cheaper price point with much easier labor.

Give BMR a call. Their stuff is top notch.

Could be something as simple as an alignment issue? Best of luck.

 

[BmacIL]

I'm on FRPP solid subframe/diff bushing, Cortex Spherical lower control arm F&R bushings, Full Tilt Boogie vertical links + upper control arm spherical bushings, FRPP toe to knuckle bearing and BMR sway bars/end links. The car has every single solid bushing available and it handles so well with stock PP shocks and Swift springs. No more lethargic feeling or midcorner understeer to snap over steer on exit.

Stiffen up the bushings and it is night and day. I had the BMR CB005 (a fantastic product in its own right) which helped immensely but not quite the solid feel I have now. But its a mod that gives you maybe 70% of being full solid, at a much cheaper price point with much easier labor.

Give BMR a call. Their stuff is top notch.

Could be something as simple as an alignment issue? Best of luck.

^^^ :clap2:

For most people the solid or even poly bushing route is too extreme on the NVH side of things, despite being superior in performance. The CB005 is the simplest and least expensive way to get the majority of the benefits without the big NVH downsides.

 

[KyBob]

Yeah that's pretty much when it does it,any time then road changes its a side to side bobble head motion,Comming in and out of a turn the car is solid,It feels like the car is allways on a weak sidewall slick,just a bunch of ass wagging,super noticable when comming onto the freeway going down hill a bit.Is what it is,I'll just live it for now.Rear sub structure bushings sound like the way to go,I'd hate to add anymore weight to an allready heavy pig,other then that the car rides nicely.I have one low speed annoying rattle that I havent found yet comming from the driver's rear,and alot of exterior air noise hitting the drivers side window,Hoping Ford can reset the window and find my rattle.I didn't buy it to wrench on it to much aside from small no brainer Bolton's.Weekend cruiser car.

I had exactly the same problem with my 2015 GT PP, changing lanes became a full contact sport. The back of the car would oscillate wildly, the faster, the larger the amplitude. I was afraid to drive on the highway. I posted sometime back and SteveW filled me in on the problem. The toe link to knuckle bolts (outer) on both sides were not torqued correctly (like about 30 ft/lbs). A torque wrench and 129 ft/lbs later, my problem was solved, like completely different car. Full disclosure, I have also installed BMR springs and cradle lockout, and now it handles like a sports car.

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