Heavy vibration at speeds about 50 mph. What could the problem be?

[BSTANGGED]

Hey gentlemen,

It's Bstangged here with a question. I have noticed lately that when I drive my 96 gt, when I get above 50 miles per hour, the car begins to vibrate heavily. I have 245/40R18 Nankang tires on 18" Saleen rims. I very positive that neither any of the rims are bent, but I was told by a body shop that had done some extensive repairs to my car that it may be the tie rod, or maybe the tires should be speed balanced. I tried the speed balancing, and no success, what is you guys take on the possible problem. Thank you for your time, and I did try the search forum with no success. Please help, its kind of scary when it occurs, feels almost like all the tires will blow out. Thanks again, and God bless.

 

[merc123]

Mine seems to get a vibration in them above 75 MPH. I'm thinking the tires could be out of balance though. Above 80 it's unreal.

 

[BSTANGGED]

ok....

Yea man, when I get to 70 and 80 mph range its horrific...But one thing I have noticed is that on asphalt highways and streets its rough, but on concrete type roads or highway its significantly smoother. If that helps explain my case any. Thanks for your help again guys.

 

[Trav4011]

Check your driveshaft.. make sure you didn't loose a weight..

 

[BSTANGGED]

driveshaft ok....thanks Trav4011

 

[soctty7676]

I've got a '98. I've replaced all tires, balanced twice, replaced one wheel cause the tire shop said it was bent, driveshaft, struts/shocks, all bushings in the front end (a-arms, springs, etc..). Over $1000 and more of my time than I care to think about. And wouldn't you know it, the f*&^% 50mph+ shimmy is still there. And you are right, it is worse on rougher roads, almost like the bumps cause something to start going out of balance.

Here's something else weird....the temperature outside effects when it happens also! I've taken it in to the shop twice and of course, didn't do it at all for them. I give up, I'm tired of wasting money and time trying to figure out what it is.

Sorry to rant, I know this doesn't help you any.

 

[BSTANGGED]

thanks anyway

well hey man that sucks. I feel your pain, i had a ongoing problem with my last car(92 honda accord) that put me through so much grief. Thanks though at least now I know that even after trying the driveshaft, that it can be a problem that I may not be able to fix. thanks for your input bro. Sorry about that. Thanks again

 

[merc123]

Mine's just the opposite with the roads. Asphalt is a little smoother but not by much. It could just be the condition of the roads. I was messing with it last night thought to see if it were the driveshaft. My logic is that if it's vibrating bad enough for me to feel it in the seat and it is in fact the driveshaft, if I downshift it should be the same or worse. Problem was it would go away or only be slight. I'm thinking it has something to do with my wheels because it's just so bad. Also, it could be my 275 tires

 

[BSTANGGED]

Thanks

Thanks a bunch guys. I am going to go to my personal mechanic today to check that out with him. I appreciate the input, and yes the vibration I can feel in the seat and its very disorienting. Thanks a milllion again and take care gentlemen.

 

[Barrier]

Mine's just the opposite with the roads. Asphalt is a little smoother but not by much. It could just be the condition of the roads. I was messing with it last night thought to see if it were the driveshaft. My logic is that if it's vibrating bad enough for me to feel it in the seat and it is in fact the driveshaft, if I downshift it should be the same or worse. Problem was it would go away or only be slight. I'm thinking it has something to do with my wheels because it's just so bad. Also, it could be my 275 tires

It'd be the same either way... driveshaft is rotating at the same speed at 55 mph no matter what gear you're in

 

[COramprat]

If it is RPM related it could be a bad u-joint. Mine would begin to vibrate at the speed you are talking about in 5th but gradually got worse. needle bearings in the DS were shot.

 

[Kurgan]

Some possibilities:

-Bent wheel
-Tire not balanced properly on wheel
-Wheel hub and/or bearing on spindle failure or mounted improperly
-Improper alignment
-Bad universal joint on driveshaft
-Driveshaft out of balance
-Bent rear axle
-Bad motor mounts
-Bad or misaligned transmission crossmember mount

 

[MBDiagMan]

I will not so much as LOOK under ANY car to inspect the driveshaft for a road vibration complaint until I have checked the tires. The tires are THE most common cause of vibrations at speed, and I mean probably something like 99 times out of 100.

Good luck with it.

 

[BooWFO]

Things I've had give bad vibes before.
Loose lugnuts
driveshaft loose
bent driveshaft
driveshaft unbalanced
spun bearing on Tloc
tires outta balance
tires flatspotted
broken belt in tire
wheels bent
wheels outta balance
broken control arm
broken torque box
bushings shot in control arms
mud in tire
ds angles messed up

 

[Yellow2002GT]

Besides tires....which usually starts around 40-50 mph vibrations......the brakes are also a huge culprit! They may feel fine when you stop but it you don't turn them and repalce the pads regularly it will cause bad vibrations! Also the front rotors have a tendacy to drag on the GT's......this can cause vibration and warp your rotors and scorch your brake pads. When I replace my stock D/S with the FRPP Aluminum one it made all the difference in the world........car was much smoother! But the bent axel is a probability too! If you run DR's and launch hard. Check the brakes......jack your front end up and spin the front tires to see if the brakes drag!

"ED"

 

[BSTANGGED]

Wow....

Thank you so much everyone, I will seriously look into all your advice...Man i love this forum, saves so much time and money. Once again thanks everyone and God Bless.


P.S - Man I drove my uncles F-350 Turbo Diesel today(aftermarket turbo installed)......All I can say is WOW...lol Take care everyone

 

[derek02gt]

vibration..

hey whats up, I am going crazy trying to figure out the vibration in my car, I live in boca raton..are you a mechanic? ive taken the car to two tireshops and they cant seem to figure out the problem..the tire place in west palm where I bought my tires keeps saying " We balanced it, its your car" but I seem to find that not true, would be great if you could take my car out for a testdrive to see if you could pinpoint anything, mustang guys usually know better then these ditzy mechanics:/

oh yea, the rims are BRAND NEW, I just got them after my previous saleen wheels had bends in them from a nasty pothole I hit in tampa, well let me know thanks.

Derrick

 

[Kilgore Trout]

It is wheel related.

 

[hvcobra99]

can any one have a step by step

Can anyone here give me a step by step on installing the Eibach pro springs and tokico adj struts and shocks

and show me a picture of your car before the eibachs and after

I would really appreciate it

99 cobra conv here with saleen body kit

 

[merc123]

I just got my Cougar's wheels re-balanced... Fixed me right up for the vibration. Now I can hear the right front wheel bearing is bad...doh!