JCus07GT

Hello I'm new to the forums sonaturally I'll introduce you to my girl Lexi. I've had a vibration for a while that developed a month after I put my aftermarket rims. This vibration caused a shimmy in my steering at 50 mph and got worse from there on. After changing tie rods, multiple Road Force balances, changing my sway bar end links, did only one of my wheel bearings and alignment, I figured the rims or tires are bad so I bought a new set wheels and tires after I noticed the back right was 1) more worn than the left and 2) unevenly worn as in some spots were bald and some still had tread. They were in commission for a year. The steering shimmy is gone with the new set of wheels/tires (I suspect the tires) but I notice another type of vibration now. I'm not mad about dishing for new wheels because the new ones still give me chills. This vibration feels as if the road is bumpy or as if I'm moving up and down slightly. My issue is that this vibration may have existed since the old wheels so I am ruling out my new wheels being the problem. (Mounting tech said they hardly needed balancing) This bumpy vibration is worse around 40 but if I'm going 80 it's silky smooth. It basically feels as its bouncing very slightly or moving slightly up and down but I can feel it from the rear. Any help? Sorry I'm desperate this is why I'm on the boards now.

JCus07GT

Pictures with old/new rims

Nuke

First, many vibration issues with aftermarket wheels are due to not removing the star washers on the studs used on the assembly line to hold the rotors in place; unecessary after assembly and cause some wheels to not sit flush on the rotor. Secondly, I've had my share of out-of-round tires as well as tires with defective belts that cause a "bounce", even though they seem to balance ok. Best bet for that is to have a shop do a RoadForce balance which can identify defective tires and wheels.

09GT/CS

Also how many miles? I didn't notice it till I started changing parts but my upper strut mounts were completely shot. The bearings completely fell apart when disassembled. After putting in the gt500 upgrades it took care of play and vibrations I never really noticed before till they were gone. Worn suspension parts can cause vibrations and uneven tire wear as you described.

JCus07GT

I think the upper strut mounts were replaced when I got a local shop to do my front struts and inner tie rods

evillela2001

This sounds like the same issues I've been having. I replaced everything you did and then some. I recently upgraded the driveshaft and it rides a lot smoother now. I haven't replaced the tires since I replaced the driveshaft but I think that will get rid of the last bit of shaking. (very very little shake now). This might be your issue but no way to know for sure. Good luck.

09GT/CS

Agreed these cars have a LOT of bushings in the suspension parts. May be a good idea to check u joints the carrier bearing and all the bushings in the rear control arms. These cars have wheel hop pretty bad in good condition. Having lots of extra play can cause weird things vibrations included. I'm still hung up on your uneven tire wear though bad shocks loose mounts bad bushings bad ball joints Ora combination of these things can cause havoc. Also replacing some parts while others in the system were borderline can cause failures. Ford has some pretty bad ball joints slop there or in the lower control arm bushings can cause issues up front and the myriad of bushings in the rear along with driveshaft play can cause lots of vibration. You've ruled out wheels and tires and some suspension components. The only thing left would be grab a pry bar and start moving things looking for excessive play. Also wheel bearings are good to check they often make roaring noise but not always when they go bad any of these can cause vibrations. Seems like your at the point of digging a bit deeper.

evillela2001

Just for reference here is what I've changed in my car to try to get rid of this issue. (although all of these parts were upgraded with aftermarket units) Sway bars, sway bar endlinks, k-member with motor mounts, control arms with new ball joints, inner tie rods and out tie rods (bump steer kit), springs, shocks and struts, upper strut mounts (camber plates), front brake rotors and calipers, upper and lower rear control arms, driveshaft and wheel bearings. Seems like a lot but like I said I upgraded everything with aftermarket parts so the car would handle better. It's not until the driveshaft was replaced that I finally noticed the issue be corrected. Could have been a bad carrier bearing this whole time. My mustang is high mileage by the way at 141K.

JCus07GT

I will have to say I considered this. Did your car make any noises from the driveline when shifting into 2nd per se and accelerating immediately? Like a clunk? I love this car but this one vibration issue really has me in a ****ty situation because I'm getting embarrassed with how much money I've thrown into it.

evillela2001

Yeah it was clunking a bit. The new shaft definitely helped a lot. It's too bad the price for a shaft is a lot so you can't just throw money around. This issue definitely has me up the wall too