Shaking

Hey I was wondering if this has happened to anyone, or if anyone can tell me what the problem may be. When I am driving at a slower speed (0- 70km) my car is smooth as usual, but right when I get to about

90-100km, the car begins to shake. It has never done this before.
Reply to
tylernagy
Loading thread data ...

just a guess but try ckecking the homokinetic joints. That's what happened to me a few years ago. Do you feel the shaking in the steering wheel? or hopefully maybe the wheels need balancing. try checking the pressure in the tyres, and see how it goes. I wouldn't reccomend high speeds with this shaking anyhow.

Reply to
neutroroberts

A couple-few of things could be happening, some of which may be instantly curable, some of which could be instantly nasty. In no particular order, they are:

Tread separation: check your tires for lumps, bubbles, or strange markings on the visible surface. Early tread separation may not be discernable at low speed. Typically, this happens on one tire, and is most overt if that is a front tire. It can be caused by defective tires, hitting too many potholes, jumping too many curbs, and so forth. If the tire blows, especially at-speed, results could be nasty.

Bad ball-joint, steering damper or other suspension bushing. This could kill you if a joint fails at any speed as you will instantly lose control of the car (the affected wheel pretty much falls off, or steering may jamb).

You lost a wheel-weight or two. Happens quite often if one is driving in bad weather, or runs against a curb, and so forth. In the process of checking your suspension and the tires, consider having the wheels rebalanced. Balance should be done at rotation in any case.

You picked up a heavy nail or screw in your tire, and it is holding the seal. But at speed, it will cause vibration.... and eventually come out with subsequent flattening of the tire... also at speed.

You picked up a chunk of ice or crud frozen into your rim. You would be greatly surprise how often this happens. Check.

One/both of your CV joints is on the verge of seizing. At slow speeds, you may not notice. This may not cause the tire to flatten or the wheel to fall off, but it may cause loss of power.

Your shocks/struts are shot. In this case, the slightest tire imbalance can set up vibrations on that wheel as the shock/strut is no longer damping anything. This can cause loss of control in a critical situation. If there are more than say.... 80,000 miles on this beast, suspect them.

GET IT CHECKED ASAP.

Only two scenario aboves are not potentially instantly deadly. And even the least-dangerous of the rest is VERY expensive if failure actually occurs.

Peter Wieck Wyncote, PA

Reply to
pfjw

It makes perfect sense that you feel the vibration strongly at a certain speed and then it even decreases as you go faster throught that point. I recommend that you stay well below that point though! It sounds as though you have a rotating imbalance -- like a missing wheel weight or road goop stuck inside the wheel rim. Your car is a dynamic system. If you were to take spring with a weight on the end of it, and you began to push the weight at a certain number of repetitions per second, you can see that if you time it right, the oscillation get larger. If you push too fast or to slowly, you will decrease the oscillations of the spring. The particular frequency is called the natural harmonic frequency. When an imbalanced car tire rotates it exerts a force on the suspension system spring. As your speed changes, the frequency of the rotating imbalance changes. When the oscillating tire force matches the natural harmonic frequency of your suspension system, you feel it most.

Sorry I wrote so much. I just wanted to strut my stuff. It took a lot of work to get a degree in mechanical engineering... But the answer is probably to just get your tires checked!

Good luck

Reply to
RepairJunkie

There are other good suggestions, but when you say shaking I presume you checked that it's not something in the engine that is shaking?

For instance is this an rpm-related phenomenon, or is it in fact related to your speed on the road? If you rev the engine while in neutral without moving the car, do you observe the shaking?

Reply to
Jem Berkes

bad tires, bad/bent wheels or bad balancing also check the suspension for worn components, tie rods, ball joints, struts/shocks, control arm bushings etc.

Reply to
dave AKA vwdoc1

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.