Stability issue

[betomax]

Hi, i love my Yaris (Sedan '08), but in past weeks i have noted some inestability when I pass over 80km\h, i get very nervous over 100km\h, my odometer is almost in 60,000 KM, the wheels were aligned and i have Balanced all my Tires/rims (ALL TIRES HAS BEEN REPLACED WITH NEW ONES SAME SPECS BUT DIFFERENT BRAND), is there something I have to check out?

Shock absorbers or some component of the suspension ?
What about Stability bars like this ?

http://img127.imageshack.us/img127/2544/motor10sj1us.jpg

please any info would be great :bow:, Thank all you.

(-_-)

[markitect]

Did the shop give you the before an after numbers from your alignment?
Did you hit an unusually large bump since then?
Also describe your instability does it wonder randomly, or is it always one direction, does the steering wheel vibrate??

[betomax]

1.- Did the shop give you the before an after numbers from your alignment?
2.- Did you hit an unusually large bump since then?
3.- Also describe your instability does it wonder randomly, or is it always one direction, does the steering wheel vibrate??

Thanks markitect by your response:

1.- No i have not numbers
2.- No absolutly
3.- well. is difficult to explain but, always when I press the brakes @t speed i wrote before, the car tail feels as if starts oscilating, and/or car front side starts charge to its left or right smoothly...:frown:

i can feel a little of vibration too on my driving wheel , the tires specs are the same as when my car was new (185/60/R15).

Original brand Brigdestone, New ones BF goodrich Traction.

[markitect]

Sounds like your wheels/tires need re-balancing, they either messed up, or a weight fell off(that does just happen sometimes).

It could also be 'warped rotors' on your brakes

[betomax]

Then i'll check that !, do you know when the brakes pads must be replaced?, on my last visit to scheduled manteinance (1 month ago ), service people told me brakes still working fine for a few months.

the brakes can add problems to this stability issue?
how do i improve in general terms the stability at higher speeds ? (80-110km\h)

Thank you again.

[markitect]

Brake rotors (or drums) with rust(or anything else) on the braking surface, will cause vibration/oscillation while braking. It doesn't necessarily mean that your brakes are worn out. If you describe the symptom to your shop they should be able to fix it pretty easily.

If the wheels are oscillating it doesn't really matter what you do for stability, the tires simply won't make good contact with the ground.