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Front end vibrations!

2K views 112 replies 49 participants last post by  Bill 
#1 ·
I've got a really bad vibration from 50 MPH +. It gets a little better under braking, but not much better.

Please read what I've done.

1.) Wheels and tires are fine. They were checked twice.

2.) Rotors have been changed out. With new bearings.

3.) Stainless steel caliper sleeves didn't help. (thanks Wayne and Richard for the idea)

4.) Flaming river rack with bump steer kit.

5.) No rag joint.

6.) New ball joints top and bottom.

7.) New tie rod ends.

any ideas????
 
#3 ·
you checked the wheel balance? thats usually the problem. also check to see if the weighs have fallen off (although mine have before with little effect)

be sure to mark the wheel and tire after the mounting and balance. if they havent dried completely after the mount, they can rotate on the rim under braking (or accel).

-james
 
#6 ·
I have a shake at around 60, on mine. Have balanced the wheels a couple of times and it is still there.....

I suspect that my spinners on my wheels may have something to do with it.

Do you have the Halibrand type wheels?
Try driving it without the spinners on the front wheels & see if your shake goes away.
 
#7 ·
Me too! I've had a front end shimmy also. I've had the front end aligned, wheels balanced twice. Never seems to improve. Very smooth up to about 50 or 55, but above that it's pretty anoying. Seems like it may be more common then any of us thought.

[ July 06, 2002, 05:12 PM: Message edited by: Barry N ]
 
#9 ·
As odd as it sounds, I had this issue on my daily driver. After 2 balances and 1 alignment I still had speed shakes between 45 and 60. The rims where balanced on the outside before and I hate that.
I had them balance with the stick on weights in the inside of the rim both times and still the shake was there. On a suggestion from a co-worker I had them rebalance with the weights on the outside. No more shake. I can't imagine why it makes a difference, I have other cars that the rims are balanced on the inside. Why it made a difference in this case I don't know. Go Figure.

[ July 06, 2002, 06:32 PM: Message edited by: Carbon ]
 
#11 ·
What kind of tire wear do you have? are the inside blocks wearing high/low? Speed shakes are a result of something out of balance. bad tire, rim, bearings loose, or balance. It seems you have eliminated a few of these already.
Did this just start? If so it may be tire related.
What parts of the equation were changed prior to this starting? A trip to the track perhaps?
I don't think control arms bushings would cause such a repeatable (only at 50mph) shake condition.

BTW, the site looks great. keep up the good work..
 
#12 ·
Bill,
If you can, put a different pair of wheels/tires on the front, even if you have to barrow a pair from a buddy. If the problem is gone you know it's your wheels/tires. Every now and then you'll get a tire that just isn't round. No amount of balancing will solve the problem.

Greg
 
#16 ·
There are 2 settings on most tire shop balance machines:
1. Static- This balances the up and down force of the tire and one weight is used (inside or outside or stick on in center) This is the setting most shops would use to balance if you do not want weights on the outside.

2. Dynamic or normal (default on most machines) This is both the up and down force (radial) and side to side force (dynamic) This is balanced by weights on the outside and inside offsetting the radial and dynamic unbalance of the tire/wheel combo. This is the best type of balance short of balancing on the car. You can do this without putting weights on the outside, but will require some trial and error and effort by the technician. Put stick on weights inside the wheel as far to the outside as you can get for the outside weight. This will be slightly more weight than the readout shows because the position is inside and at a smaller diameter than the machine expects. After the outside reading is zeroed, put weight on the inside as normal to zero the balance there. I spent many years doing this, so I know it works with wheels with a deep inside like the Mustang and Cobra wheels.

Find a good tire shop and make friends there.

Of course no amount of balancing will cure a vibration from an out of round tire.

Good luck.
 
#19 ·
Bill -

I had a similar problem like this on my BMW 540 with 18" wheels and aftermarket suspension and brakes. Did all the things you have; turns out my wheels were very slightly out of round. I needed to get the tires shaved every 4-5K miles.

I had them checked for lateral runout, but that was OK. Turns out the bolt centers were very slightly off. After slight shaving, everything would be OK for 2-3K miles then it came back. Three tire shops never found it, a race shop I work with finally checked and figured it out. The error is less than 0.1" but multiplies with tire wear.

The wheels are in a box in my sideyard now!

Worth looking into.
 
#23 ·
Me too.

FR 18:1 rack

stock calipers

new rotors/bearings

new upper/lower ball joints

Bought new 15" BFG TA Tires up front

poly offset rack bushings

stock lower CAs

PS GT40 wheels

I've had the wheels balanced three times now and front end aligned twice. Checked the studs and lugs for proper seating. The front end feels good and tight but I still get the 55 mph vibration. I'm taking it to a specialty shop that races vintage mustangs to nail it down.
 
#24 ·
Same problem here.I'm beginning to think that what we are seeing is the road surface being transmitted through the steering gear to the steering wheel.With the manual rack,solid bushings,and solid u-joints all of the vibration dampening is gone from the system and has no where to go but into the wheel.You can feel the vibrations in your regular power steering car,but they are damped out by the time they get to the wheel and feel very faint.To make it worse throw in 17" wheels and a car that weighs nothing.I really hope I'm wrong because it means we'll have to figure out some kind of dampener set up.What we need is a glass smooth road to prove or disprove this idea,but here in the pothole capital of the state if not world I have yet to find said road.Let's keep fighting this thing,there's an answer out there somewhere.Pete.
 
#25 ·
From my service manual:
Shimmy,Shake or Vibration:
1.Out of balance tire or wheel.
2.Excessive wheel stud runout.
3.Excessive brake drum or rotor imbalance.
4.Worn tie rod ends.
5.Wheel trim imbalance.
6.Worn lower ball joints.
7.Excessive wheel runout.
8.Excessive loaded radial runout of tire and wheel assembly.

Does anyone else have any other causes to add to the list?
 
#26 ·
I'm surprised at how common this is. Seems like we're all trying the same thing too, multiple attempts at balancing and alignment with little or no improvement.

Is the common thread here the BF Goodrich Radial T/A tires? Is everyone that's having this problem using the Radial T/A's? Should we be pushing BF Goodrich for a resolution?

Who else makes tires in the sizes we need for 15"?
 
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