It feels as if the shimmy originates from the rear tires..It could be something loose in the rear - a shock mount or suspension bushing..
Even new tires can be a problem as well as the balance job..

Does it matter whether the car is under power or if you're coasting? It's the same regardless of whether you're coasting or under power, suspect wheels and/or tires. If it stops vibrating or if the vibration changes when you go from power to coasting, it could be a CV joint or in the transmission. You might want to look over the tires carefully to see whether you have a bunch of stones stuck in the treads. I drive a fair amount on gravel roads, and my driveway is gravel, and I can definitely tell a difference as far as vibration when the treads are full of gravel. It smoothes out as they work their way out.

When you get up to 70-80 mph, that's a pretty high speed, so even small things can throw off the balance.

Hello,

It makes no difference if I am coasting or underpower. I took the car back and had them re-balance the tires, they were able to get them under 11 on the machine? I am not sure what that was but they told me that under 25 was good. I don't drive on gravel roads at all, but I will take a look after work just to be sure. I was thinking of swapping the front tires with the rear tires and see what happens.

The reason this bugs me so much is that I like to drive at 70 mph to work and back, I get the best mpg that way, but if I want a smooth ride, I have to be doing 80+ or under 70, and if I do under 70 everyone tends to follow too close. So I really need to get a smooth ride at 70.

Static

Well, if they balanced the wheels, I'm sure they removed any debris from the tread. If they didn't, the wheel would be balanced with the junk in there, and that wouldn't be good since it would be out of balance when it falls out.

I hope the balancing solves the problem. Did they mention how far they were out of balance when they first put them on the machine? It could also be a tire defect if the balance doesn't cure it, and as you said, swapping the wheels front to back should help you isolate the problem if it's related to a wheel or tire.

I had them balance them 3 times within a week of buying the tires, at 2 different shops. I have had them for about 2 months now. I watched them the third time, in fact the guy doing the work asked me to come watch them balance them. None of the wheels were over the 25 to start with, they told me that they were ok but they got them down to under 11 (The display on the machine). If I have time after work, I will swap the front with the rear and post the results tomorrow. I will be happy to replace what ever is causing the problem, I just don't want to start throwing parts at it with out knowing what is really causing the problem.

Thanks,

Static

Morning,

I switched the wheels, front to back. The drive in to work was the same, the whole car shakes a bit. If I put my hand on the door I can feel it more then when I just hold the steering wheel.

Static

Static:

It sound like it's definitely a problem with the balance on the tires. How many miles on them, and also on the car? What is the tire brand? I think those are 13 inch tires,?? which seem to be harder to get a good balance than 14 or 15 inch. Another thought would be a tire or tires, that with a small defect that isn't noticeable, such as a belt that has shifted.

I'd take it to another shop and see if they can get this corrected with another balancing. You may have to ask around to find a shop that actually knows what they are doing, or with different equipment. If your previous tires were not causing vibration, it would be most likely that your new set needs attention.

Here's a link for ya.

GG

Here is a link that might be useful: Balancing info

Maybe slow down 80 is against the law anyway and even 70 might be not sure about your state?Let the idiots that follow to closely pass you.If your not on an interstate the speed limit is 55?

Out of balance wheel/tire/rotor assemblies cause vibrations, primarily at the steering wheel,
at 55 to 60 mph (their sour spot).
No one ever seems to balance the rotors anymore..
When I balanced wheels, the entire unit was spun ON THE CAR, this is the way it should be done,IMO..
With the "whole car shaking", the rear rotating assemblies should be checked and balanced - it could be rear bearings(too loose - for instance)

Update:

I jacked up the car yesterday and checked for play on each wheel. I found no side to side play on any wheel and no up and down play on any wheel. The struts are fine and the shocks are new. Tires are balanced.

A friend came by and asked me about the rotors, I told him they need to be replaced but I was waiting until the pads need replacing. They are warped, they shutter when I press on the brakes. Now that I read the post from Earthwarm, it seems that the rotors may be my problem. I am going to get new ones and I will post the results. If this does not do it, then I was thinking of putting the spare tire on and driving it until I find the tire that has to be bad. But hopefully replacing the rotors does the trick.

Static

If your problem is only recent to the install of new tires, I think that's where you'll end up with a solution to this problem.

Even though you mention brake pulsation likely due to warped or defective rotors, a change in balance to this part would only occur if a major amount of material was removed or lost, and that is very unlikely to have happened.

Substituting the spare to find the problem tire may not work if the balance problem is on all the tires. Even switching tires front to back may not work to locate the problem, but I would do that first before trying a spare tire. Another point is, if you have a mini-donut for a spare, that won't work at all, since they are only designed for 50 mph or so, and the balance on those is poor.

GG