bouncing ride

My '97 Miata with 80K miles has an annoying ride. Even on smooth
roads, if I hit a normal street manhole cover, the car bounces around.
I know it is supposed to have a firm ride, but this seems dangerous...
going around a curve and hitting a small bump results in a little side
skid.

I checked the shocks by pushing down on each corner of the car - no
bouncing on the rebound, but it is very firm.

Is it possible that the shocks are worn out, yet still do the job of
eliminating rebound? Will replacing with a softer set help?

Pushing down on the car to check the shocks on a Miata will not work !
Your shocks were all done at about 30K. Time to change. Buy some GOOD
ones that will last and you will be happy. :-)

Bruce RED '91

Thanks Bruce - Can you recommend a particular brand that will give a
good ride?

I think that you should go to, "Miata.net" and look on Marketplace. The
price and kind of ride is so open that you should look at all makes.

"KYB AGX"or "KYB AGN" are good. "Koni" has an adjustable height
setting. "Tokico" is another one.
The adjustable kind will let you pick the right feel that you want and
are about the same price as the "stock" shocks.
I have "Koni Yellow" on my '91 and when set on a low setting, the ride
is about like "stock". I crank mine tighter when I Autocross. (Never
run them "full soft" on the settings! The valves do not work properly.
1/4 turn off full soft works well.)

Hope this helps :-)

Bruce RED '91

On 10 May 2005 18:51:11 -0700, "bokuglen" > wrote:

>My '97 Miata with 80K miles has an annoying ride. Even on smooth
>roads, if I hit a normal street manhole cover, the car bounces around.
>I know it is supposed to have a firm ride, but this seems dangerous...
>going around a curve and hitting a small bump results in a little side
>skid.
>
>I checked the shocks by pushing down on each corner of the car - no
>bouncing on the rebound, but it is very firm.
>
>Is it possible that the shocks are worn out, yet still do the job of
>eliminating rebound? Will replacing with a softer set help?
Just a thought - have you checked your tire pressure? When I bought my
Miata, the tires were exactly 38 psi. Changing them to a more
realistic 30 psi did wonders for the ride.

Natman wrote:
> On 10 May 2005 18:51:11 -0700, "bokuglen" > wrote:
>
> >My '97 Miata with 80K miles has an annoying ride. Even on smooth
> >roads, if I hit a normal street manhole cover, the car bounces
around.
> >I know it is supposed to have a firm ride, but this seems
dangerous...
> >going around a curve and hitting a small bump results in a little
side
> >skid.
> >
> >I checked the shocks by pushing down on each corner of the car - no
> >bouncing on the rebound, but it is very firm.
> >
> >Is it possible that the shocks are worn out, yet still do the job of
> >eliminating rebound? Will replacing with a softer set help?
> Just a thought - have you checked your tire pressure? When I bought
my
> Miata, the tires were exactly 38 psi. Changing them to a more
> realistic 30 psi did wonders for the ride.

Even so, if he hasn't changed his shocks at 80k, he should. Adjusting
tire pressure now would be putting a bandaid on the problem. My '91
has 77k miles and shocks are on the to-do list for the summer. I'm
going with KYB AGX from Ebay. A set of four runs you just under $300
that way, and many other members report getting good shocks this way.
They are new, just way cheaper than if bought anywhere else.

Sorry Guys, but I have to rant about this one.

I think unless you are going to offer good advice, then do not offer any
advice.

To say that the shocks are knackered after 30k is absolute rubbish.

First of all mileage has nothing at all to do with shock wear, 80k on good
roads will affect the shocks far less than 80k on bad roads,
Mileage is an extremely rough gauge and only a gauge, a car with 80k may
well have worn shocks, but I have had Miatas coming into the shop that have
done 100k+ and drive better than they did new, my 94 only had its shocks
changed last year, after over 130k and 10 years.

Secondly a visual check of the shock will give you far more information than
looking at the milometer, granted access is very tricky, but you need to
carefully peel back the shock boot and check if any of the shocks are
leaking.

Correct tire pressure a Band-Aid!!!!!
Your tire pressures are not a band aid mate they are a SAFTY ISSUE, and the
cheapest ever handling fix you will ever get.

If you are running a Miata at 38psi its going to handle like a Hippo on ice,
only with less grace.
If there are any suspicions about handling 9 out of 10 times its down to
tires, if you put 10 people in a car with worn shocks, then replace them and
give them another drive 9 out of the 10 won't even notice!!!!
We once had a guy come to us for a service, we did the full service
including adjusting his tire pressures, after he picked it up he came back
in total amazement, he asked if we had fitted new suspension!!!

This is the order I would tackle any handling problems.
1/ Tire pressure and wear, and doubts about wear change the tires, you will
only ever usually have 1 high speed blow out in your life.

2/ Check the shocks for wear, leaking fluid on the stanchions is a big give
away, also bouncing the car can give a very rough gauge, you need to bounce
the car up and down about 3 times, when you are as far down as you can go,
then let go, what you are looking for is the car to settle within the return
bounce, if the car keeps bouncing up and down then it means you really need
to have the shocks checked.

3/ go round you suspension with a torque wrench, check all the nuts and
bolts are at the required torque settings, we have seen many rear sway bar
bolts come off, giving the symptom you mentioned.

4/ If all above are ok then get your alignment checked, make sure you get a
good shop though, as getting it set incorrectly is going to mess up
everything.

And come on guys lets not jump to conclusions that can end up costing people
loads of money, think about what you are writing before you press send,
making such sweeping statements doesn't help anyone.


Cheers Mark.



"Anthony" > wrote in message
oups.com...
>
> Natman wrote:
>> On 10 May 2005 18:51:11 -0700, "bokuglen" > wrote:
>>
>> >My '97 Miata with 80K miles has an annoying ride. Even on smooth
>> >roads, if I hit a normal street manhole cover, the car bounces
> around.
>> >I know it is supposed to have a firm ride, but this seems
> dangerous...
>> >going around a curve and hitting a small bump results in a little
> side
>> >skid.
>> >
>> >I checked the shocks by pushing down on each corner of the car - no
>> >bouncing on the rebound, but it is very firm.
>> >
>> >Is it possible that the shocks are worn out, yet still do the job of
>> >eliminating rebound? Will replacing with a softer set help?
>> Just a thought - have you checked your tire pressure? When I bought
> my
>> Miata, the tires were exactly 38 psi. Changing them to a more
>> realistic 30 psi did wonders for the ride.
>
> Even so, if he hasn't changed his shocks at 80k, he should. Adjusting
> tire pressure now would be putting a bandaid on the problem. My '91
> has 77k miles and shocks are on the to-do list for the summer. I'm
> going with KYB AGX from Ebay. A set of four runs you just under $300
> that way, and many other members report getting good shocks this way.
> They are new, just way cheaper than if bought anywhere else.
>

On 11 May 2005 09:13:17 -0700, "Anthony" > wrote:

>
>Natman wrote:
>> On 10 May 2005 18:51:11 -0700, "bokuglen" > wrote:
>>
>> >My '97 Miata with 80K miles has an annoying ride. Even on smooth
>> >roads, if I hit a normal street manhole cover, the car bounces
>around.
>> >I know it is supposed to have a firm ride, but this seems
>dangerous...
>> >going around a curve and hitting a small bump results in a little
>side
>> >skid.
>> >
>> >I checked the shocks by pushing down on each corner of the car - no
>> >bouncing on the rebound, but it is very firm.
>> >
>> >Is it possible that the shocks are worn out, yet still do the job of
>> >eliminating rebound? Will replacing with a softer set help?
>> Just a thought - have you checked your tire pressure? When I bought
>my
>> Miata, the tires were exactly 38 psi. Changing them to a more
>> realistic 30 psi did wonders for the ride.
>
>Even so, if he hasn't changed his shocks at 80k, he should. Adjusting
>tire pressure now would be putting a bandaid on the problem. My '91
>has 77k miles and shocks are on the to-do list for the summer. I'm
>going with KYB AGX from Ebay. A set of four runs you just under $300
>that way, and many other members report getting good shocks this way.
>They are new, just way cheaper than if bought anywhere else.
First the symptoms described (rides too firm) fit too high tire
pressure better than worn shocks.

Second, if the tire pressures are too high, spending hundreds of $ on
new shocks won't fix it. Calling it a "bandaid" is just wrong. If the
pressures are too high the ONLY way to fix it is to lower them.

Third, while it is certainly possible, maybe even likely that his
shocks are worn out, it is hardly the 100% certainty you make it out
to be.

In article >, "gixer" >
wrote:

> my 94 only had its shocks
> changed last year, after over 130k and 10 years.

That doesn't mean they weren't worn out at 30k (or 50k, or whatever). It
just means you waited far too long to replace them. If Greek roads are
as poor as you've described them, I'd think you'd be lucky to get 20k
from OEM shocks.

> Secondly a visual check of the shock will give you far more information than
> looking at the milometer, granted access is very tricky, but you need to
> carefully peel back the shock boot and check if any of the shocks are
> leaking.

A visual check will tell you nothing about internal wear. Leaking is
only one mode of shock failure, and far from the most common. Bouncing
on the bumper of a Miata is pointless. The first sign of failing shocks
on a Miata is usually bottoming in the rear when going through dips.

Of course, a Miata with defunct shocks can still be driven sedately for
years, with only a ride penalty, as long as hard cornering or braking
aren't required. Poise under stress will be absent, though.

---
Lanny Chambers
'94C, St. Louis
http://www.hummingbirds.net/alignment.html

Hi Lanny,

You are right you could drive for many miles with defective suspension, if
the car is driven as you say sedately, then most people would not even
notice the suspension is defective.

My shocks were knackered the rear right in particular was leaking badly,
after I replaced my shocks I gave the old ones a good check over, 3 were
still operating very well.

As for wear and tear, as far as car components go the shock absorbers have a
relatively easy life of it.

The Basic but most widely used type of shock the Twin Tube design, works on
the principle of fluid displacement and heat convection.
By forcing a piston through oil or gas or oil and gas, shocks develop the
hydraulic friction necessary to oppose the unwanted bouncing in your
suspension.
The hydraulic fluid located in the damper body, is forced through tiny holes
(Orifices) in the piston head as it travels (compresses or rebounds).
However, the orifices let only a small amount of fluid/gas through the
piston, which in turn slows down spring and suspension movement.

So the basic make up of a shock absorber are Piston, Valves, shock body,
plus various seals washers nuts etc,
Shock bodies are very sturdy usually only damaged in impacts,
Piston failures are extremely rare, more often but still rarely dirt can
cause internal wear and/or blocked/worn valves, as nearly all shock are very
well sealed this is fairly rare,
The 2 main reasons for shock failure are Contamination of the oil/gas, by
various factors like excessive heat, or external interference like moisture
But still the main failures as far as my experience goes are seals
bursting/leaking,

Internal wear as you say, only occurs if a seal is either leaking or burst,
which will then cause wear, do to less lubricant being inside the body, as
near on all the moving components within a shock body are immersed in some
form of lubrication during both cycles, internal wear in a non leaking shock
is extremely little.

Because the Miata and most sport orientated cars have a firm ride with very
limited suspension travel compared to a standard family car, it is often
very difficult for the average driver driving sedately to tell if his cars
shock absorbers are worn, for you to make such a sweeping statement that
"The first sign of failing shocks on a Miata is usually bottoming in the
rear when going through dips" again is complete rubbish,

This is such a generalisation that it makes it a completely useless
statement, there are not any accurate or consistent methods of measurement
in that statement, there are so many variables, like ride height, spring
strength, weight inside of the car, the speed at which you took the dip, not
to mention the fact that 1 mans dip is another mans crater.

Lastly I would bet a month salary, that if you took the average driver, put
him in a standard Miata, with standard non trimmed bump stops, and got him
to drive through a dip of your choice, he would not even tell the difference
if he even hit the bumpstops, the transition is that smooth.

I am not saying shocks do not wear before 30k, of course some faulty units
will wear straight after fitment, what I am saying is that there is in no
way shape or form, enough evidence to go around telling people in such
confidence that their shocks are worn, the poster said the car had done 80k,
the author of the reply did not even know if the shocks were changed in that
time, advice is greatly appreciated, everyone here has been extremely
helpful when I needed advice, I just think we have a responsibility to think
about what advice we give.

Cheers Mark.



"Lanny Chambers" > wrote in message
...
> In article >, "gixer" >
> wrote:
>
>> my 94 only had its shocks
>> changed last year, after over 130k and 10 years.
>
> That doesn't mean they weren't worn out at 30k (or 50k, or whatever). It
> just means you waited far too long to replace them. If Greek roads are
> as poor as you've described them, I'd think you'd be lucky to get 20k
> from OEM shocks.
>
>> Secondly a visual check of the shock will give you far more information
>> than
>> looking at the milometer, granted access is very tricky, but you need to
>> carefully peel back the shock boot and check if any of the shocks are
>> leaking.
>
> A visual check will tell you nothing about internal wear. Leaking is
> only one mode of shock failure, and far from the most common. Bouncing
> on the bumper of a Miata is pointless. The first sign of failing shocks
> on a Miata is usually bottoming in the rear when going through dips.
>
> Of course, a Miata with defunct shocks can still be driven sedately for
> years, with only a ride penalty, as long as hard cornering or braking
> aren't required. Poise under stress will be absent, though.
>
> ---
> Lanny Chambers
> '94C, St. Louis
> http://www.hummingbirds.net/alignment.html