Lately my 92 f250 4x4 has been a little funny with my front end suspension getting crazy bouncing from the right side i think. I dont know what it is and it does feel a bit funny when i drive it, suspension wise, and when I approach 40mph it gets crazy . Could someone give me any ideas what it may be and what i could possibly do to fix this demonic front end.

 

i dont know how mechanically inclined you are, but id start be shaking down the front end. (i.e. check ball-joints, tie-rods, wheel bearings) ive had steering components cause some really strange behavior. a lost wheel-weight could also be to blame, but as far as supension, the basic check for a broken shock or spring would be all that i can think of at the time. ill ponder it awhile and get back with more if i can... best of luck

 

After you check the suspension as FordPower suggested, if that results in nothing obviously wrong, have the wheel rebalanced. Sometimes the weights fly off and you can get some serious vibrations that way.

I replaced my front tires last year with decent looking junkyard tires, and took them to a shop to be balanced, and no problem below 55. 56 and higher the front was squirrely and vibrated like crazy. Had it rebalanced (for free at the same shop) four more times.

Turned out the darn wheel wasn't round, and the tire followed the not-so-round shape of the wheel.

Replaced the wheel with the wheel on my useless spare, and viola, perfect balanced was achieved.

There is a lot of force exurted on a tire both in weight, and in rotational force (centrifugal force). Doesn't take much to make things wobble funny.

 

that reminds me of road force variation... i learned about it at tech but i dont remember what the hell it means exactly. i know it has something to do with the driveability and handling of the tire/vehicle

 

Looking at the tread of the tire...
-Static balance is up and down
-Dynamic balance is side to side (camber balance)

Wheel force variation is caused by many things... wheel runout, out of round tire (meaning the sidewall is different measurements around the perimeter of the tire, meaning when mounted, the tire is off-centric to the axle), stiff spots - i.e. the sidewall at point "A" is stiffer than at point "B". Usually not a problem with truck tires because they have larger sidewall dimensions, but usually is painfully obvious on those side-wall free tires people are buying these days with 20" rims.

Tire pressure also affects wheel force variation - more pressure - more vibration if something isn't correct.

Variations in sidewall stiffness can be balanced out by some of the newer, fancier machines that shops have.... but out of round (off-centric) tires were just improperly moulded and I'd return them in a heartbeat as even though some shops can balance them, the end result is you still have an egg-shaped tire on your truck.

Another common problem is how the wheel sits on the backing plate - i.e drum or rotor. I cannot tell you how many times people I know have complained about vibrations, and the shop couldn't figure it out after balancing the wheel several times. A friend of mine was going through this and there was a small piece of stick stuck to the back of the wheel, which got smashed almost flat when mounted on the studs. Almost flat, but not completely flat. Because the balancing machine balances using the center hole, no one noticed this.

 

ill check the front end. Thanks yall i appreciate it and ill get back with the results. But I might have more questions

 

Checked your tire presure lately? In additon to the stuff mentioned above, i've seen low (pretty low) tire pressure alone cause that. Frederic, you mentioned it but it sounded a little more like you were talking about high tire pressure making a different problem worse.
Jerry

 

If the problem is sidewall stiffness variation or sidewall compliance variation, then higher pressures exhaggerate the effect of the variations. In all other causes of wheel wobble lower pressures aggrevate it.

Of course i'm talking extremes here. Minor variances which all tires have due to manufacturing processes can easily be balanced out.