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Front end shake

Posted By: floridian

Front end shake - 06/04/14 06:22 PM

Have had this since my car got back on the road after its rotisserie resto.. Front end shakes from 37-41 mph. Kinda of oscillates for a second or two, smooths out, then does it again.. 4500 miles.. Have had the front tire/wheels balanced 3 times by different places.. Everything new, did use poly graphite for front end, including lower..

Smooths out after 41 mph and runs great up to 100..

Only thing not new were used front tires ( age unknown) that had 15 miles on them.. All three rebalancers checked the tires and called em good...

Any thoughts here?

Attached picture 8165413-5554552-vertbaseball2.jpg
Posted By: dynorad

Re: Front end shake - 06/04/14 07:48 PM

Do you feel it in the steering wheel trying to shake the wheel side to side or is it the front end sheetmetal that is shaking?
Posted By: RapidRobert

Re: Front end shake - 06/04/14 08:42 PM

Quote:

Have had this since my car got back on the road after its rotisserie resto.. not new were used front tires ( age unknown) that had 15 miles on them.. Any thoughts here?

toss another set of spare tires on the front & take it out for a trial. Still bad then jack up the front end & check everything till you find what is loose
Posted By: 340SHORTY

Re: Front end shake - 06/04/14 09:20 PM

Replace the lower Poly bushings with factory style rubber 1s. The polys allow the lowers to move in and out a little.
Posted By: RapidRobert

Re: Front end shake - 06/04/14 09:33 PM

Quote:

Replace the lower Poly bushings with factory style rubber 1s. The polys allow the lowers to move in and out a little.

Ding ding ding we may have a winna I thought the descrip sounded different from anything that I had ever heard of regarding that type of deal
Posted By: floridian

Re: Front end shake - 06/04/14 09:57 PM

Quote:

Do you feel it in the steering wheel trying to shake the wheel side to side or is it the front end sheetmetal that is shaking?



Both, but not real bad and like I said only at that speed and it varies and comes and goes...

Seems more like you can see the front hood and fenders kinda shake a little besides just feeling it..

My 85 year old dad went for a ride last weekend and he even asked what the shake was....
Posted By: floridian

Re: Front end shake - 06/04/14 10:03 PM

Quote:

Quote:

Replace the lower Poly bushings with factory style rubber 1s. The polys allow the lowers to move in and out a little.

Ding ding ding we may have a winna I thought the descrip sounded different from anything that I had ever heard of regarding that type of deal



Trust me, it is a very unique shake that comes and goes every few seconds and only at that speed.. wish I had an extra set of wheels and tires to try out, that would be the first step..

Will possibly change out the lower bushings eventually. Just not ready to chase after it by changing out parts at this point..

Attached picture 8165680-5554552-vertbaseball2.jpg
Posted By: RapidRobert

Re: Front end shake - 06/05/14 12:42 AM

Quote:

wish I had an extra set of wheels and tires to try out, that would be the first step..

I agree shotgunning parts ain't the way to go about it. What about swapping the front wheels/tires for the rears & retrying it and when you had em balanced did you balance all 4 and did they go back on the same corners they came off of
Posted By: mopar_man

Re: Front end shake - 06/05/14 03:40 AM

The tires could be in balance but still be out or round. balance is static , out of roundness is dynamic ..........or is it the other way around? Jeez, getting too old to figure it out any more lol . anyway try another set of tires on the front before you start throwing parts at it
Posted By: floridian

Re: Front end shake - 06/05/14 01:50 PM

Quote:

The tires could be in balance but still be out or round. balance is static , out of roundness is dynamic ..........or is it the other way around? Jeez, getting too old to figure it out any more lol . anyway try another set of tires on the front before you start throwing parts at it



This is actually what it feels like, out of round tires, but why only between 37 - 41 MPH?? I purchased the front tires out of a persons attic, they did not fit on the front of his Nova....

Rear wheels and tires will not fit up front, too wide.....
Posted By: 69topless

Re: Front end shake - 06/05/14 10:32 PM

Do you have a front drums or disc brakes? I was dealing with shaking, but during breaking. It turned out the aftermarket Magnum 500 wheels does not fit properly on heavy duty drum, which had the air vent fins. Simple but took me a while to discover the issue, also were checking tires few times with no result.
Posted By: mopar_man

Re: Front end shake - 06/05/14 10:33 PM

Quote:

Quote:

The tires could be in balance but still be out or round. balance is static , out of roundness is dynamic ..........or is it the other way around? Jeez, getting too old to figure it out any more lol . anyway try another set of tires on the front before you start throwing parts at it



This is actually what it feels like, out of round tires, but why only between 37 - 41 MPH?? I purchased the front tires out of a persons attic, they did not fit on the front of his Nova....

Rear wheels and tires will not fit up front, too wide.....








because That speed is the "Goldylocks zone" where the harmonic balance of the car and tire match up and then you have a vibration . Much like a drive shaft , lets say you have a very minor bend in the drive shaft , you won't feel the vibes until your in or near "the zone". Get tires and wheels and give it a try .
Posted By: Dcuda69

Re: Front end shake - 06/05/14 10:44 PM

Did any of the balancers use a "road force" type balancer. They actually put a load on the tire and measure sidewall stiffness as well as loaded diameter and more. Great machine for finding odd tire related vibrations. A good tire store should have one(they are pricey..about 20-25K )
Posted By: Magnum

Re: Front end shake - 06/06/14 06:03 AM

Out of round is pretty easy to check too.

Jack up the car and spin the wheels. Look at the runout on the tread surface. The bead area of the rim should be almost zero.
Posted By: floridian

Re: Front end shake - 06/06/14 01:40 PM

11" front drums, no fins.. Wheels/tires checked by multiple tire people.. Balanced on coats type balancers..

Yes, the "zone" comment on here makes sense.. It is a speed the car seems to "settle" into..

IF they were out of Round would they not get worse as speed increased?? As said above 41 ( and under 37) car rides great..
Tires are radial TA's....

Again, not a constant shimmy...comes and goes within a couple of seconds....

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Posted By: Magnum

Re: Front end shake - 06/06/14 07:36 PM

Quote:


IF they were out of Round would they not get worse as speed increased??



You can drive out of the vibration IF it's indeed out of round. In fact out of round is more obvious at slow speed. You will attract alot of attention with my next test but stick your head out the window during bumper to bumper traffic on the highway. Watch the tire. If the UP/DOWN = one complete revolution of the wheel, then it's out of round. Not necessarily the one you are looking at either.
Posted By: RSNOMO

Re: Front end shake - 06/06/14 08:10 PM

LCA bushings would be WAY down on the list...

I've run urethane for a lot of years(and miles)...

No issues...


Were the front wheels and tires spun on the car???
Posted By: floridian

Re: Front end shake - 06/10/14 01:54 PM

No, machine balanced off the car...
Posted By: Ply72rr

Re: Front end shake - 06/10/14 11:40 PM

Are your front tires a different diameter then the rear? You seldom have a tire perfectly balanced and with different diameter tires the heavy spots will match up briefly and then go out of phase as the car travels down the road giving you the couple of seconds of vibration and then smoothness you mentioned. I think this was refered to as the rollong drum effect in the text books when I was in high scool. Maybe adding some balancing beads to the tires would help. Trying a different set of tires/wheels if available would be a good idea to narrow down possible causes.
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