Dalton Hill
Member
When i go about 80mph or around 75mph. My st vibrates, is this normal. If it is not what should i do. i have had the tires rotated and balanced.
Vibrating at 80mph?
- Thread starter Dalton Hill
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Richard Toms
Well-Known Member
Sounds like a shock problem. I'm sure once you do this upgrade, it won't vibrate at all anymore.
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- V8 engine
- What year is your Sport Trac?
- 2010
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- 2n Gen Owner
could be driveshaft, ball joints, bent axle, a bunch of stuff.....
Common are drive shaft and shocks..
Todd Z
Common are drive shaft and shocks..
Todd Z
I had this same problem after I had new rims/tires put on that were "balanced" (and it only happened between 70mph and 80mph). I took it back to the shop, where oddly enough it was not in balance. I would go back to the place you had it balanced and tell them, they should take off the wheels and rebalance, for no charge (if you just recently had it balanced) and if the problem still occurs, then it may be one of the things listed above by Todd or shvdnlayd.
Brett Wustman
Active Member
I am guessing it's the tires as well, I have had this problem twice with my truck and both times, it was taken care of by new/rebalanced tires.
Brett
Brett
Johnny O
Well-Known Member
Belt shift in tire, out-of-round tire. Also it's a truck, it won't ride like a Cadillac at 80 mph.
Todd is correct.
Wheel and Tire balance issues will show up at speeds below 70 MPH. andy vibration above 70 MPH are cause by drive line harmonics and particularly the Drive shaft.
Ford did a recall on many early model Sport Tracs to replace the old steel drive shaft with an aluminum unit, because of vibrations at speeds above 70 MPH.
...Rich
Wheel and Tire balance issues will show up at speeds below 70 MPH. andy vibration above 70 MPH are cause by drive line harmonics and particularly the Drive shaft.
Ford did a recall on many early model Sport Tracs to replace the old steel drive shaft with an aluminum unit, because of vibrations at speeds above 70 MPH.
...Rich
William Washington
Active Member
Not always so. I just had new tires put on a couple weeks ago and the vibration only occurred above 75 MPH. Drove me nuts on a trip I took to Arizona that week.
When I got back I went to the installer and they rebalanced my wheels and now it rides smooth as glass.
Dingo
Well-Known Member
My new tires caused a vibration between 96 and 118, Until I redid the balance.
wwashing,
Sorry, but I disagree. They may have said they rebalaned the tires, but I don't beleive that was the actual problem. They may have done something stupid like leaving the lug nuts loose on one wheel and did not want to admit to that problem. The other posibility is a defective or out-of-round tire (yes even new ones can be defective).
Vibrations from an out of balance tire will become most noticable at about 35-45 MPH and often disappear by about 60 MPH. Almost any good automotive repair manual will tell you that. Anything that falls outside those parameters would not just be a simple wheel balance issue... There was something else that they didn't tell you or they don't really know what fixed the problem.
The larger the diameter of the item out of balance the lower the rotating speed is necessary to set up the vibration...Thus smaller diameter items like drive shafts will require higher speeds to produce vibrations do to out of balance conditions.
A common problem is getting the heaviest side of the tire mounted on the heaviest side of the wheel. A good tire shop should spot this if they have problems balancing the tire and/or they are stacking more than a few ounces of weight on one side of the wheel. That tire should be remounted about 180-degrees on the wheel.
...Rich
Sorry, but I disagree. They may have said they rebalaned the tires, but I don't beleive that was the actual problem. They may have done something stupid like leaving the lug nuts loose on one wheel and did not want to admit to that problem. The other posibility is a defective or out-of-round tire (yes even new ones can be defective).
Vibrations from an out of balance tire will become most noticable at about 35-45 MPH and often disappear by about 60 MPH. Almost any good automotive repair manual will tell you that. Anything that falls outside those parameters would not just be a simple wheel balance issue... There was something else that they didn't tell you or they don't really know what fixed the problem.
The larger the diameter of the item out of balance the lower the rotating speed is necessary to set up the vibration...Thus smaller diameter items like drive shafts will require higher speeds to produce vibrations do to out of balance conditions.
A common problem is getting the heaviest side of the tire mounted on the heaviest side of the wheel. A good tire shop should spot this if they have problems balancing the tire and/or they are stacking more than a few ounces of weight on one side of the wheel. That tire should be remounted about 180-degrees on the wheel.
...Rich
- Joined
- Sep 21, 2003
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- 22,366
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- Long Island, NY
- What engine do you have?
- V8 engine
- What year is your Sport Trac?
- 2010
- What Generation is your Sport Trac?
- 2n Gen Owner
Hey rich,
Welcome back, good to see you......
I just want to add, are they placing the rim with the most amount of weight on the Right rear and working towards the drivers side ?????
Also are they placing weight on the outside of the rim ??? Sometimes you have to deal with stick on weights or ugly weights on the outside just to make them not vibrate.
And is the "rounding" off on the balancing machine, that ca do it to when the machine rounds up or down to make the weight .25 .50 or .75
Todd Z
Welcome back, good to see you......
I just want to add, are they placing the rim with the most amount of weight on the Right rear and working towards the drivers side ?????
Also are they placing weight on the outside of the rim ??? Sometimes you have to deal with stick on weights or ugly weights on the outside just to make them not vibrate.
And is the "rounding" off on the balancing machine, that ca do it to when the machine rounds up or down to make the weight .25 .50 or .75
Todd Z
Yardsale
Well-Known Member
I think there are no absolutes.
There is a vibration diagnosis chart in the Vibration Chart folder of my library.
There is a vibration diagnosis chart in the Vibration Chart folder of my library.
Kyle Keller
Active Member
my sport trac was vibrating around 70 real bad. good shocks, brand new tires and wheels, aligned. i took out my 4wd driveshaft and it was rusted and little warped and it solved the problem my sport trac does 100 with no shudder haha
David Ponder
Well-Known Member
Dingo.. 118? Wow.. Didnt know a ST would go that fast.. haha Dave
Gerald Pierce
Well-Known Member
My wheels are lug centric and after getting them balanced and rotated, about half the time I get the same indication. If I do, I just jack it up, loosen the lugs and retorque them in the air.
It helps, but I still get a little.... i consider it a "quirk" in my ST and just live with it until I can get different style wheels. Or at least that is my excuse to get new wheels when I tell my wife that I am spending the money
It helps, but I still get a little.... i consider it a "quirk" in my ST and just live with it until I can get different style wheels. Or at least that is my excuse to get new wheels when I tell my wife that I am spending the money
Dingo
Well-Known Member
Dave, mine's not exactly "stock," but a stock V8 ST will easily do that much and more when you remove the governor from the equation.
Dan Long
Well-Known Member
cruzrtwdgt, why don't you add a set of hub rings? They're only about $20 a set and will help keep your wheels seated properly, although if you're using wheel spacers you probably won't be able to use them.
