Looking to improve harsh ride from KYB AGX

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I recently purchased a '97 in excellent condition and would like to keep it that way.  I bought it with some auto-x ambitions, but the reality of my schedule and new baby on the way have me searching for a (relatively) more comfortable ride.  Let's say touring more than track.  It came with KYB AGX shocks, Eibach Pro-Kit springs, Racing Beat front and rear sways, 16quot; Kazera Light wheels, Fuzion ZRi tires and an aggressive alignment.  Does anyone have any suggestions on which of these or other components I could change to improve the quality of the ride, particularly over real world bumpy roads?  I thought about going back to stock springs if I can find them, but I am open to other solutions.

Welcome and congrats on the new baby..I have a 3 month old, so get ready if your not used to having a little one around.  Would you mind telling us what size tires you have and if possible what is the height of the ride from edge of the fender to the center of the wheel.  This will help the guys here with their analysis.  Believe me they can tell alot by the way a car sits and what is on it.  You could start trading parts on your car for stock stuff in the classifieds.  If you would like to go back to that particular suspension.

The KYB AGX when set on one are softer than the original Miata shocks.  Unless they are blown, they are not the problem.  The AGX really aren't suiting to anything with a higher rate than the stock springs, so my guess would be that the eibach springs are the primary source of your uncomfortable ride.  The 16quot; wheels are on the large size for the Miata as well, and that short sidewall affects ride quality. I have no personal experience with the Fuzion tires so I don't know if they're known for having a hard sidewall.

I have a similar setup on my 96 with AGX's and Hamp;R race springs on 15 inch oem wheels.  The ride is very harsh and over any dips/bumps, the car shakes really bad.  I have taken it to an alignment shop, my personal mechanic and my buddy who races his miata in spec miata and they all told me they can't find anything wrong with it.  I was told maybe it's the springs rates on the springs, worn bushings, too much air in the tires or dampening setting.  Can anyone tell me what else it may be?

I'd look in Da Dumpster for a set of stock springs then visit Fat Cat Motorsports for a set of modified NB upper mounts and progressive bump stops which will increase the bump travel and vastly improve the ride on bumpy roads or broken freeways.  Keep the RB sways and except that I have Konis you will have the same suspension I enjoy on the street.  Don't lower the car much, if at all.  Look in this forum for lots of archived discussions of lowering Miatas.  
The aggressive alignment should not affect ride quality but could result in a darty car if the front is toed out.  I've gone with Lanny's specs except for 0.5° less negative camber all around than he suggests; ride, handling and tire wear are all very good.  You'll need to realign anyway after you've had the suspension apart.  


Originally Posted by EunoStar
I have a similar setup on my 96 with AGX's and Hamp;R race springs on 15 inch oem wheels.  The ride is very harsh and over any dips/bumps, the car shakes really bad.

What are your heights? Wheel hub centre straight up to fender wall. Don't the Hamp;R springs lower the car 1.5quot;? Maybe you're riding on the bump stops and when you go over a bump you are smashing down on the bumpstops, which if they are stock will give a harsh jarring ride.

Mine was like that once....I put some FCM bumps and fixed it up.
They Rule!


Originally Posted by Rogue Miata
Mine was like that once....I put some FCM bumps and fixed it up.
They Rule!

Here Here! I'm running the KYB AGX's with FM 315/255 springs, added the FCM bump stops and the ride is much less harsh.

Thanks to everyone for the quick reply, this is a great forum.  As for additional info, my Fuzions are 205/45 R16's and the measurements from the fender to the wheel center are 12.25quot; in the front and 12.50quot; in the rear.  I have been running 29psi in my tires.

I believe your AGX's may be cooked at that ride height. If yopu still have the stock springs use them with some non adjustable shocks KYB or Koni's new SRT make sure you have decent bumps and you should have a very comfortable ride that will last for a very long time.
and FleaBay. You should be able to get them cheap.

I have Kyb AGX with FM springs.
Dont find that harsh at all.
You`d be better off with something else than those crappy eibach springs though.
They are way too low and way too soft...
-n

I had Eibachs with KYB AGX shocks (also with stock shocks).  The ride was either bouncy with the shocks turned down or harsh when turned up.  I replaced the springs with FM's old springs and their shock tops.  The ride is much better, though exceptionally rough roads still feel rough.  I run my shocks 5F/4R.
A set of 15quot; or even 14quot; wheels with more compliant tires like Toyo T1-Rs will help with the ride as well.

Tell us your static ride height measured this way:
From wheel centers up towards the fender lip.


Originally Posted by Irish Wildcat
the measurements from the fender to the wheel center are 12.25quot; in the front and 12.50quot; in the rear.

Too low. I think you're riding on the bump stops. You definitely need FCM bump stops.


Originally Posted by Irish Wildcat
Thanks to everyone for the quick reply, this is a great forum.  As for additional info, my Fuzions are 205/45 R16's and the measurements from the fender to the wheel center are 12.25quot; in the front and 12.50quot; in the rear.  I have been running 29psi in my tires.

Bump stops alone will not help anything. At that ride height you need much stiffer springs You should be at least 450# in the Front and 350# in the rear springs as well as shorter bump stops.Your AGX's are most likely shot at that height and there is no way that they could ever handle the spring rates you need to ride that low.At 450 front and 350 rear you will spend a lot of time on the stops at 12.25 and 12.5 By the way I am not criticizing your ride height I am at 12.25 and 12.75

AGX's are ment to be used with stock springs.  Quaility bump stops will mask some of the harshness but the original problem is still there.