G D vibration!

[Magicape]

I'm still getting a washboard like front end vibration around 80 M/Hr after new tires, perfect alignment, and three balances--balance is perfect.
Somewhere I read about "pre loading" the steering which solved the problem. Anybody know how this is done or adjusted? Talked to the local dealer and have an appointment next week but I have low expectations from them. Service manager told me that Ford does not warrentee for speeds above the speed limit when I told him it was worse at 80. I'm afaid they'll screw around with the alignment and balance and make things worse! The vibration is harmonic--coming and going every 1-2 seconds or so. Thanks for any input--Hank

[Magicape]

I'm still getting a washboard like front end vibration around 80 M/Hr after new tires, perfect alignment, and three balances--balance is perfect.
Somewhere I read about "pre loading" the steering which solved the problem. Anybody know how this is done or adjusted? Talked to the local dealer and have an appointment next week but I have low expectations from them. Service manager told me that Ford does not warrentee for speeds above the speed limit when I told him it was worse at 80. I'm afaid they'll screw around with the alignment and balance and make things worse! The vibration is harmonic--coming and going every 1-2 seconds or so. Thanks for any input--Hank

Maybe "washboard" is the wrong description--the steering wheel vibrates back and forth--feels just like a front tire out of balance, but not, and it's harmonic--

[Marauderjack]

Mine does the same damn thing!!!! I have never gotten the ride out of the second set of tires that I got from the factory ones!!!

I have had mine balanced twice and on the machine they look fine...at 75-80 MPH the vibration comes and goes about every couple of seconds and sometimes goes away completely for 30 seconds or so???

I think some of the guys have had them "Road Force" balanced which takes into account "hard spots" in the tires and treats them as a heavy spot...makes sense but nobody around here knows what I'm talking about!!!

Marauderjack

[Magicape]

Mine does the same damn thing!!!! I have never gotten the ride out of the second set of tires that I got from the factory ones!!!

I have had mine balanced twice and on the machine they look fine...at 75-80 MPH the vibration comes and goes about every couple of seconds and sometimes goes away completely for 30 seconds or so???

I think some of the guys have had them "Road Force" balanced which takes into account "hard spots" in the tires and treats them as a heavy spot...makes sense but nobody around here knows what I'm talking about!!!

Marauderjack

I've heard about the road force balance. Basically, as I see it, with this suspension set up minor out of balance will be felt--but mine is dead nuts, and the curious thing is the harmonics--this would not happen with a normal balance problem--others have commented on it. Someone wrote about a dealer changing the "pre load" on the steering and the problem went away. I wonder if it has anything to do with the self adjusting steering feel dependent on speed?

[MERCMAN]

Had the same problem at 80 MPH. Got all 4 tires Road-Force balanced, had the alignment preformed to MARAUDER specs,(available here on the site). The vibration disappeared after that. Hope this helps. Be positive that the alignment is Marauder specs, NOT GM.

[Magicape]

Had the same problem at 80 MPH. Got all 4 tires Road-Force balanced, had the alignment preformed to MARAUDER specs,(available here on the site). The vibration disappeared after that. Hope this helps. Be positive that the alignment is Marauder specs, NOT GM.

Could you feel the harmonics--the vibration coming and going? The alignment is Marauder spec.

[MERCMAN]

Could you feel the harmonics--the vibration coming and going? The alignment is Marauder spec.

The best way to describe it would be a vibration around 80, after that speed it would never completely diasappear, but it would "come and go". If that is what you are referring to as harmonics, then yes I felt it. The balance took care of it.

BTW didn't Alvin from the Chipmunks have a harmonics problem??

[Magicape]

The best way to describe it would be a vibration around 80, after that speed it would never completely diasappear, but it would "come and go". If that is what you are referring to as harmonics, then yes I felt it. The balance took care of it.

BTW didn't Alvin from the Chipmunks have a harmonics problem??

OK, I give up. Have an apointment to road force balance Saturday am. I'll report results on Monday. Still can't rationalize why the harmonics and why a balance problem would cause that---???

[SergntMac]

OK, I give up. Have an apointment to road force balance Saturday am. I'll report results on Monday. Still can't rationalize why the harmonics and why a balance problem would cause that---???

Well, this seems to be the way it is with a full frame automobile with the performance profile of our suspension. It's a new design for the Panther beginning in '03, and every design has what somone could call a flaw, or side affect. On our MMs, even a rear tire out of balance will telegraph forward, and up into your hands, mirrors, and so on.

Rack and pinion steering is by far the best design for our cars, yet it's side affect is that while you have a better feel for the road, you get more feedback from the road, and points in between you and the road. If you really come to need to adjust the rack, it's coverd by a '98 TSB on the Mark VIII, your dealer should be able to look it up.

[Pantherman]

[QUOTE=Magicape]I'm still getting a washboard like front end vibration around 80 M/Hr after new tires, perfect alignment, and three balances--balance is perfect.

Are you really sure you have perfect balance, or are you just trusting the techs output from an out of calibration machine. I doubt that low mesh load on your rack and pinion would cause anything as severe as what you describe. To cause the type harmonic interaction you mention, I think you would need multiple vibration sources coming in and out of phase. Assuming you do have perfect balance, one way this could happen would be to have an out of round tire and wheel combination on at least one front and one rear corner. Because of their different diameters, the front and rear wheels turn at different speeds. That means front and rear vibrations in the vertical plane would sometimes be additive and sometimes they would be trying to cancel each other out. If this is the problem, a good road force balance should catch it.

[David Morton]

So many misconceptions, so little time. *sigh*

The first law of automotive vibration says that ALL vibrations on cars are caused by things that are spinning. DOH! (Ga-aw-lee, Sargent Carter, I never woulda guessed it!)

Roadforce balancer. Sounds really high tech, right? Well it's not. It's a tire balancer that has a roadforce measuring attachment on it, and programming for the computer to use it. The new machine from Hunter now has a drum for the tire to roll against at slow speed. The tech moves it up against the tire and locks it in place and turns on the machine which then measures the resistance of the slow roll it induces to detect any hard spots in the tire. If there are any, the tire must be discarded! It will never be alright and there is no way to balance out the hard spot. This is a relatively rare condition, especially with these high dollar tires.

Out-of-round tire/wheel assembly. Ususally this is felt at a certain speed, 55-65 mph on most passenger car tires, provided they're properly balanced. Before it, smooth as glass, after it, still nothing. But at that certain speed, a steady continuous vibration (with one out-of-round tire). I've never had the occasion to see this in a low profile tire, but I suppose the speed for this type could be higher.

Vectoring is where the high spot of the tire is matched (aka, vectored) to the low spot of the rim. (If a tire or rim is out of specs, they must be replaced.) The new Hunter machine tells the tech where the high and low spots are, but he must dismount and remount the tire to match them up. More work. I always used to just find the low spot of the rim before I put the tire on and used the blue dot indication for the high spot of the tire (a DOT requirement) to vector mount. If your tires are not vectored properly, a R/F balancer will fix your problem, as well as check for a bad tire.

Harmonic vibration. This happens when something vibrates, perhaps not noticeably, at a frequency that causes some other component, like a steering wheel or column to vibrate noticeably, like a tuning fork. The steering wheel has a harmonic "sound", a specific frequency, that if slighly induced by a matching frequency, like from a tire or the engine, will cause it to "wake up" and vibrate. Adjusting the rack pre-load would change it's frequency as well, but it still would have to be something else (that's spinning) causing the "seed" vibration. That this vibration you have "comes and goes" tells me you have two things, each vibrating a little that converge at times adding up to a lot of vibration that comes and goes. This is called a harmonic convergence.

In the final analysis it sounds to me like you're getting a run-around by a tire shop that either doesn't know what it's doing or is trying to blow you off rather than fix their mistake.

Before you got the tires, no vibrations, right? Then right after you get the tires, this condition you describe all of the sudden appears and somebody's saying what?- the rack is bad? I'm sorry, why do new tires expose a bad rack? Go back to where you bought the tires and demand satisfaction. I cut my mechanics teeth on front-end alignments and tires and I have never seen alignments or steering components cause vibrations of any kind. Vibrations are always caused by round things that spin fast. Duh! Also, a tire balancer that is off it's calibration won't balance the tire, if the guy using it is using it properly. He should put the weights on and spin it again to check it. If the machine is off, it'll tell him that tire needs more weights, ad infinitum, and he'll know something's wrong with the machine. My guess is the tires aren't mounted right, given they've checked the balance and say it's right. Out-of-round wheel assemblies sounds likely.

Anyway the tires are the problem! And don't go to that dealership that says it doesn't warrantee for speeds in excess of the speed limit. A statement like that is just setting you up so they don't have to fix your problem. First off, you don't have to exceed the speed limit to properly install and balance tires designed to go 148 mph. If they vibrate at 80 or higher, they're not right at 65 either. You might not notice it on the car but the equipment they use to do the job ought to. Balancers go to 1/4 oz, some even measure tenths. It takes a lot more than that to shake the tire at 80. Mine goes 120 and is smooth as a baby's ass and I got mine installed at Firestone on a dinosaur of a tire balancer (not a roadforce machine) with the guy eye-balling the placement of the weights!

Secondly, if he says something like that to a Marauder owner, you don't want to do business with him in the first place. Ask him if the initials F.O. mean anything to him.

[David Morton]

[QUOTE=Pantherman]

... To cause the type harmonic interaction you mention, I think you would need multiple vibration sources coming in and out of phase. ...

Very good observation Pantherman. Do you suppose it could be TWO tires not properly mounted and/or balanced?

Too easy.

[TooManyFords]

I've had the same problem with my tires, even after having the fronts road-force balanced. I watched the tech at the machine and when the first tire came up "marginal" (but within specs) I knew I was in trouble. But what can you do? Tire Rack will only take the tire back if it fails. Marginal is ok in their book.

I will NEVER buy BFGs again. Period. So far thay have all failed in one way or another.

Again, this is my humble opinion and please don't flame me for it.

David, great 411 on tire balancing. My next set with the custom rims will be correct in every way.

Cheers

John

[Marauderjack]

Ahem......

I have gone on several tire manufacturer's site and NOBODY makes these damn sizes...especially the rears!!

I have even thought of putting the fronts in the rear and buying a bit smaller tire for the front to keep the TC and ABS happy but cannot find anything that will look good!!

I guess I could go to 17" CV Sport wheels and the options would be more numerous?? I wonder why Ford made this mess?? There had to be other options!! The BFG rears are crappy......end of story!!

Any ideas??

Marauderjack

[MM03MOK]

David - excellent information. Please feel free to copy to the Reviews section for further reference. Also add the correct Marauder alignment specs so we have a place to point folks for answers to these ever-popular questions. Thank you!!