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Defective kyb = vibration 60-70mph?

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Old 05-14-2010, 09:17 AM
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Default Defective kyb = vibration 60-70mph?

When I bought the car 2 months ago it had dryed out tires and vibrated really bad on the highway but I figured it was just bad tires. I installed new wheels and tires(balanced) and drove the car yesterday to lower it a bit and to an allignment. The car still vibrated and felt very jumpy and i felt a bit of steering play. We tightned the steering box and helped the play. I still feel slight play, but I just figured that is normal for a 20 year old car?

As we began trying to lower the car with the coilovers, we noticed that the (front/pass) side wouldn't drop. We even lowered the perch all the way down on that side and it still wouldn't lower. We ended up raising the front drivers side so the car would be even, and did the allignment. Anyways, I drove the car home and the car is still vibrating.

So my question is, could this all be due to a bad shock? How can I test it?

(rear just for example) we lowerd the front all the way down and it still didn't drop.


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Old 05-14-2010, 09:26 AM
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the shock does not control the ride height...unless it was seized.
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Old 05-14-2010, 09:34 AM
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Defective KY generally results in friction, not vibration.
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Old 05-14-2010, 09:36 AM
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This couldn't possible be the infamous "65mph shimmy" could it?
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Old 05-14-2010, 09:36 AM
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Searching 65mph shimmy now!!!
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Old 05-14-2010, 09:51 AM
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F that shimmidy ****. Just found a a big crack on my dash because of it. I get it at 55 and 80-90.
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Old 05-14-2010, 09:57 AM
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Originally Posted by luiml73
Searching 65mph shimmy now!!!
You'll probably have more luck at miata.net, since it affects almost every miata.

You need a good balance on your tires if you don't want to drive a paint shacker.
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Old 05-14-2010, 10:02 AM
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SHAKE IS NOT SPELLED WITH C. a
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Old 05-14-2010, 10:11 AM
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Thanks fellas. Looks like I'll be looking for a better place to balancing my tires. So should I look for a shop that has one of these hunter machines?
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Old 05-14-2010, 10:25 AM
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Originally Posted by luiml73
Thanks fellas. Looks like I'll be looking for a better place to balancing my tires. So should I look for a shop that has one of these hunter machines?
Yes. You want a Hunter Road Force balance with no more than a road force of 10-12 on the fronts. You can live with a 25 on the rears. The shop may have to dismount the tires, turn them and remount a couple of times. Mine did.

Go to Hunter's site and they have a shop locator that has their equipment on there.
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Old 05-14-2010, 10:49 AM
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Or you can just invest in some decent bracing.

Frame rails, harness bar and a roll bar made mine go away. Now that I've taken those off I'm afraid to see how it rides on the highway. Another stock Miata headache I'd forgotten about...
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Old 05-14-2010, 10:58 AM
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First picture looks strange. I don't remember seeing coilovers installed on top of a perch.
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Old 05-14-2010, 11:04 AM
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is the sleeve taller than the shock body? They must be shortened if so. I have a feeling the body is riding on the sleeve...
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Old 05-14-2010, 11:23 AM
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I get the shimmy at like 35 mph and ~65 mph
Balancing doesnt seem to get rid of it
so idk, Miatas are weird
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Old 05-14-2010, 11:25 AM
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Originally Posted by Braineack
is the sleeve taller than the shock body? They must be shortened if so. I have a feeling the body is riding on the sleeve...
Can't see pics at work, so missed this, but yes, the eBay sleeves ARE longer than AGX shock body. When I did this last year before getting real suspension I had to cut nearly an inch off mine.
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Old 05-14-2010, 11:26 AM
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i had to as well on my konis....
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Old 05-14-2010, 01:52 PM
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Originally Posted by Braineack
is the sleeve taller than the shock body? They must be shortened if so. I have a feeling the body is riding on the sleeve...
I will have to look into the sleeves but how do I measure this? I guess I will need to remove the coilovers first and go from there. If anyone has a link or a pic of hoe to measure this I would appreicate it. Sorry for my ignorance, but this is my first time owning coilovers.
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Old 05-14-2010, 02:20 PM
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I'm still not getting how the car can't be lowered? Did you screw down the collar and then let it sit on the ground?
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Old 05-14-2010, 02:28 PM
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the sleeve must be such that the collar does not extend past the shock body. if it does, the collar with hit the perch once compressed and severely limit your shock travel. there's a chance that the body is resting on the collar and that's why the car cannot lower and rides like ****.
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Old 05-14-2010, 03:33 PM
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well the car lowered just fine on all three sides when screwing down the spring seat. The front passenger side however didn't lower at all when I adjusted seat all the way down.
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