G D vibration!

  • Thread starter Thread starter Magicape
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Two things can be responsible for detectable vibration--input and sensitivity. We usually attack input and forget sensitivity. If you are convinced your rotating stuff is round and balanced, you may want to look at sensitivity (loose steering rack/shaft/column, suspension, instrument panel or grounded body mounts).
 
VicsEvilBrother said:
I set everything at 30 or 32 cold. Are you talking about 38 hot, or 38 cold?
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38 cold.

30 or 32 cold is too low. Even Ford realised this and raised the recommended pressure from 32 to 35 for the '04s. It took a while for us to figure out that even 35 was too little for the rears. Those "in the know" normally run 38-40, some even more, but I find the ride becomes unacceptable above 38. I keep the fronts at 35.
 
RF Overlord said:
Those "in the know" normally run 38-40, some even more, but I find the ride becomes unacceptable above 38. I keep the fronts at 35.
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Me too. 35 psi front and 38 psi rear.

Even the Road Force Balance can be botched up. My last set of front tires was mounted about 18 months ago. A day after the new front tires were balanced, I had to take a trip up to Baltimore (about 200 miles round trip). Along the way, I noticed a vibration right at the 75-80 MPH mark.

Upon returning, I called the dealer and told them it wasn't right and took it in for a rebalance. Something wasn't done correctly the first time around or it threw one of the sticky weights because the rim wasn't cleaned properly before applying them. I guess most people don't notice, don't care, or won't say anything about it. I am not one of those people.
 
Yeah I was personally there when the tires were road forced all times, it's not the balance that is a problem. I also personally rechecked them on a machine that I have use of. If a shop won't let me watch the tech, I go somewhere else. These rims are too expensive to leave alone.
 
Vibrations drive me crazy and I do everything I can to track them down and eliminate them. Heres my list of vibrations and what the causes were..

I installed 4.10s and had a vibration 45mph-80mph.
Cause- The rear rotor was frozen onto the axle and I had to use a hammer to remove it, This damaged the rotor. I replaced all 4 rotors and the vibration went away.

I installed new tires and even after balancing I had a subtle vibration at highway speeds
Cause- The yo yo who replaced the tires and balanced them didnt do a great job scraping the adhesive off where the old weights were on the rims. I cleaned the insides of the rims very carefully and had them re-balanced. There was a couple ounce difference on all rims. After the re-balance the vibration went away.

For no reason what so ever a vibration started from 35-50 MPH range
Cause- Balance weight flew off. Had tire rebalanced and vibration went away.

I replaced sway bars and had a vibration around 75-85MPH
Cause- Driver side sway bar end link loosened up. I tightened everything up again and the vibration has gone away.

So far so good.
 
VicsEvilBrother said:
My MM has the front end shimmy too. It's been re aligned several times to my specs, no change. New tires, new wheels ($$$$$$$$$), several road force balances later, still shimmies if you get it at just the right speed. And it's cyclic. The only thing that has stayed constant is the type of tire -- the really super awful KDWs. It's gotta be these horrible tires. Since I have a tuner I am going to break down and buy a matched set of 4 good quality tires at some point. The not-that-old replacement rear KDWs are wearing at an alarming rate w/ highway only driving, no burnouts, no blasting off w/ them. I think they are made out of recycled, compressed, ... well never mind what I think.

G-dammit.
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All the high-speed tire and wheel info has been good. But if you can't get that vibration to go away and you're sure you're tires/wheels are round/balanced don't forget to look for slop in your tie rods and steering rack.

Lifespeed
 
vibrations

I have had the steering wheel vibrations since about 20k miles, just after I realigned to the "carfixer alighment spec", nothing before that. I blamed the somewhat worn original tires, and bought all new tires from the dealer, made no difference. The Ford service tech was brought in from Virginia to diagnose the problem, and he decided to replace three of the four wheels, no change. I had the alignment checked at three different alignment shops, and road force balanced at least six times at four tire shops (in two states), no change. Recently had the dealer try the TB for the rack preload adjustment, no change. By the way, the TB is for a body bushing torgue adjustment, not steering rack preload. That is a diffent type of service notice for MMs built within a certain time period. I have spent hundreds of dollars chasing this problem, and nothing solves it. I called customer service for BFG, but they refused to discuss it, suggested that only a tire dealer could determine if it's the tires, but the reality is that they can't understand the problem either. One time I spoke with Dennis Rinehart about it, and he suggest a lightweight driveshaft - more hundreds of dollars. I am beginning to believe that the BFG tires are absolutely no good, and likely, they are the culprit, but what can we do?
Magicape said:
After reading all of this I just sent a friendly mail to BFG Engineering and Warrentee Departments, suggesting they read this thread--let's see if they reply--
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hbarret, I am (slightly) comforted that I am not the only one who has spent a fortune chasing the minor high speed vibe on this car. The driveshaft is not the issue at 60 mph, w/ the vibration in the steering only and not the body. You will feel a driveshaft vibe (which I've had before w/ balance problems) in the chassis as well as the steering.

I will report back once I toss the KDWs for something better
 
Marauderjack said:
BFG tires ARE the problem
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I've had 2 sets of stock BFGs on The Blackbird and no vibrations to speak of.

...or maybe I'm just not hyper-picky.

I did have a steering wheel vibration when Phoebe was first acquired. Turned out the Pirelli Direzionale tires on the front were swapped L/R. I put them so they rotated in the correct direction and the vibration was gone.
 
I thought I might be the only one with this problem too.
My stock tires from the factory were perfectly fine no problems.
But when I replaced them with the same BFG's after they wore out that is when my problem started. Some where around 70 to 80 mph the front end wants to shimmy a little, like a strong wind is trying to blow my car off the road. I had them rebalanced with no real changes.

So from what I am reading here it might be the brand of tires, I guess next time around I will be trying a different brand and go with a 255/50-18 in the rear in place of a 245/50-18, only a minor difference in height.
 
RF Overlord said:
I've had 2 sets of stock BFGs on The Blackbird and no vibrations to speak of.

...or maybe I'm just not hyper-picky.

I did have a steering wheel vibration when Phoebe was first acquired. Turned out the Pirelli Direzionale tires on the front were swapped L/R. I put them so they rotated in the correct direction and the vibration was gone.
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If you spend hours at highway speeds driving on different surfaces.....what you think was surface feedback all of a sudden gets on your nerves and you realize it is the darn pulsing minor vibration!!!:mad2:

I had it with all replacement BFG's and do not have it with the Nittos...so I think it is the BFG's??:confused:

It's funny how these little irritations always seem to manifest themselves at THE SPEED YOU WANT TO GO!!!!:argue:

Marauderjack:cool:
 
I have had the same vibration through the steiring wheel from day one after driveing off the dealers lot. I to chalked it up at the time thinking a wheel weight fell off and needed to be rebalanced. I went through the same as many other marauder owners have in trying to chase the problem and found no satifactory results. Cleaned wheel hubs, rebalanced three times with RF, torque mounted wheels, checked alienment. I to have come to the conclusion in agreement the culprit is the OEM BFG tires. In the spring a will try another brand since the rears are running thin. To bad since the front tires still have some miles left.
 
Yeah when you road force the tires and wheels are measured for out of round, that is not it. I am going to end up taking off a set of front KDWs w/ 2k miles on them but that is life. I am almost tempted to change wheel size because of tire availability. If the stock wheels didn't look so damn good, I would downsize to 17s for better availability.
 
I was considering 17" rims too, if I can't find an all season 255/55-18 (or equal) to replace the BHG's
 
If I could find a bolt on set of 17s that looked close to our wheels, I'd do it in a heartbeat. I know the new body style Mustangs have a bulgy 5 spoke that is "torque thrust" -style, that isn't all that dissimilar to our wheels, in that it's 5 spoke and bright polished / clear coated. I don't know if they are 17s or 18s though. I know going down to a 17 will induce more sidewall flex, but honestly, sidewall flex from a slightly taller tire on a 4200 lb boat with so much body roll from the stock suspension, is not going to be the limiting factor for handling by a long shot.

CRAP, here are the wheels I was thinking of:
3648.JPG


Also 18x8.5s, so that wouldn't help me. Dammit!
 
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Magicape said:
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
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i had a 02 cv p71 and had the same problem check out your front wheel bearings
 
I changed out the front wheel bearings on the MM, which didn't change anything. The first thing dealers seem to change is front wheel bearings for any type of noise/vibration issue. I have yet to see that actually be the problem. Especially for these guys who have had the vibe since "day one". It's not a wear part causing it if the car came from the factory doing the high speed shake. I'd bet anything mine did.

My shaking is minimal and pretty easy to ignore most of the time. What seems to make it worse is if the car has been sitting a long time -- the shaking seems to be worse the first few highway miles. This tells me it's a pretty sure bet the KDWs are the problem.
 
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Darn, I need a new set of fronts on mine. I have had good luck with BFG KDWS in the past, that they were 255/50/17, and mounted on a '97 with recirculating ball steering, not rack and pinion.

I think I'll try a set of the KDWS at my local America's Tire. If they vibrate, I guess one of the other options would be those $200 Goodyear F1s. Anybody try these?
 
I too have the harmonic vibration at 75-80 mph. Thought it was one of my rims being slightly out of round. I have the stock BFG's on.

I have not tried the GY F1's, but would like to hear what others think of them.
 
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