Loose Front End

My '03 Miata has 5,400 original miles on it (I know, I know, I'm not
driving it enough!). Ever since it was new, I've noticed that if I
drive along uneven pavement, perhaps a ridge parallel to my course, it
sometimes feels like the car is being nudged or shoved left, then right
off its track. The sensation is NOT transmitted to the steering wheel,
or at least I don't notice it. It's almost as if the front end is loose.

I keep the low-profile tires inflated to around 28 - 29 psi. Under
normal driving, the car seems to track fine.

What might be causing this?

Alan
'03 SE

AlanRab > wrote in:

> My '03 Miata has 5,400 original miles on it (I know, I know, I'm not
> driving it enough!). Ever since it was new, I've noticed that if I
> drive along uneven pavement, perhaps a ridge parallel to my course, it
> sometimes feels like the car is being nudged or shoved left, then right
> off its track. The sensation is NOT transmitted to the steering wheel,
> or at least I don't notice it. It's almost as if the front end is loose.
>
> I keep the low-profile tires inflated to around 28 - 29 psi. Under
> normal driving, the car seems to track fine.
>
> What might be causing this?

My guess is tires. If you changed tires to some with different tread the
problem would probably go away. If you have the front AND rear checked to be
sure nothing is amiss, then I'd not worry about it, it seems fairly normal
behavior.

In article >,
AlanRab > wrote:

> Ever since it was new, I've noticed that if I drive along uneven
> pavement, perhaps a ridge parallel to my course, it sometimes feels
> like the car is being nudged or shoved left, then right off its
> track.

That's called "tramlining." It's common with performance tires that are
past their prime, but in your case I'd suspect an alignment problem, in
particular insufficient toe in. A good alignment will probably cure it,
as well as improve your Miata's handling so much you'll think it's a
different car.

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

Lanny Chambers wrote:

>
>
> That's called "tramlining." It's common with performance tires that are
> past their prime, but in your case I'd suspect an alignment problem, in
> particular insufficient toe in. A good alignment will probably cure it,
> as well as improve your Miata's handling so much you'll think it's a
> different car.
>
> ---
> Lanny Chambers
> '94C, St. Louis
> http://www.hummingbirds.net/alignment.html

Since his car has only 5000 or so miles, it probably has the factory
alignment, and the tires are 2 to 3 years old now.

This is almost exactly the situation that I had when I bought my '96M in
1999. It had only 10,000 miles and fairly decent Bridgestone Potenza
tires, but they were getting old and heat-cycled, and it still had the
*way off* factory alignment.

When I took the car in, had Bridgestone RE-71 tires mounted, and had it
aligned according to Lanny's specs, it really did feel like I was
driving away in a different car, the improvement in control and handling
was amazing.

I drove the car straight from the tire shop to the alignment shop. While
I noticed an improvement with the new tires, it wasn't that different
until I had the alignment done. Then the combination of sticky rubber
and precision alignment almost seemed like magic.

Pat