Do sway bars wear out

[Jason77]

Do suspension parts like springs and sway bars loose there stiffness with age and make the car not handle as well as it did when it the parts where new

[rb30]

yes

[Jason77]

Thanks....i thought they would.

[RacingManiac]

Spring sags, sway bars might fatigue and actually breaks...

[targa]

Do suspension parts like springs and sway bars loose there stiffness with age

...no

[Matra et Alpine]

...no

erm YES for most and NO for some - depends on the alloy used
Lightweight racing ones may go more brittle, predominatly standard steel ones fatique 'softer'

[targa]

erm YES for most and NO for some - depends on the alloy used
Lightweight racing ones may go more brittle, predominatly standard steel ones fatique 'softer'

just foolin guy....

you said "erm"

[Alastor]

Do suspension parts like springs and sway bars loose there stiffness with age and make the car not handle as well as it did when it the parts where new

Assuming the springs are properly designed and loaded the springs will not wear out in the sense that the material or spring stiffness changes. However, as they are cyclically loaded they will be subject to fatigue failure.

There are many cases where springs are not optimally designed for the given load conditions. In these cases the spring can take a “set” which reduces the ride height of the vehicle. Although, the spring may be shorter the material stiffness and spring stiffness are mostly unaffected. On the other hand any change in ride height usually has a significant effect on handling.

More Information :: http://www.stockcarproducts.com/spgtech.htm


Similarly, if the sway bar is properly designed and loaded no appreciable change will occur in the material stiffness during the components life. Also as with a spring the cyclical loading will eventually result in fatigue failure of the sway bar.

Fatigue failure is hard to predict accurately as it depends on many variables. For example, depending on design goals a part could have a design life as low as 100,000 cycles or as high as 100 million cycles.

[targa]

?'d

[Blue Supra]

good info from alastor yet again, this guys gold.

i have found that stuff does wear out, you should see the stock parts i pilled out of my datto

[Matra et Alpine]

Assuming the springs are properly designed and loaded the springs will not wear out in the sense that the material or spring stiffness changes.

Sorry Al, they do.

Competition springs at a MUCH higher rate than stock - especially rallying ones which can go softer in a few rough forest events !!

Adjustments in coil length are constantly required as the springs set.
THIS affects the suspension operation - though in reality with an adjustable coil platform this can be re-adjsuted back in to the spring arte. However as this increases it DOES take affect.

However, as they are cyclically loaded they will be subject to fatigue failure.

Designers in the last 20 years have the advantage of computer aided design to prevent the fatique points which lead to failure - though in springs THE most common is for the tip to shear if they are 'cheap'.

Although, the spring may be shorter the material stiffness and spring stiffness are mostly unaffected. On the other hand any change in ride height usually has a significant effect on handling.

Sorry Al, I have to disagree - though I accept in stock it is insignificatn - but a spring can EASILY soften by 10% over it's first inch of travel as it "wears".

and the same is true of anti-roll ( aka sway ) bars though to a lsesor extent UNLESS runnign REAL stiff bars - because they are subjected to less movement over a greater length and hence less metal realignment due to flexing.

[2ndclasscitizen]

if your car is really low, going over kerbs, gutters, speed bumps annihilates them (as well as bumpers)

[Matra et Alpine]

if your car is really low, going over kerbs, gutters, speed bumps annihilates them (as well as bumpers)

too true - and rocks in the ditches

[RacingManiac]

Interesting point was talked about by Peter Elleray about his Le Mans Bentley was the car's rideheight change over 24 hours, as cars typically loses as much as ~5mm to 1cm in ride height over the period.....it was particular interesting as Bentley 2003 was running Torsion bar....

[Alastor]

Sorry Al, they do.

Competition springs at a MUCH higher rate than stock - especially rallying ones which can go softer in a few rough forest events !!

Adjustments in coil length are constantly required as the springs set.
THIS affects the suspension operation - though in reality with an adjustable coil platform this can be re-adjsuted back in to the spring arte. However as this increases it DOES take affect.

I was assuming the poster was taking about street use, but you know how assumptions go. So for my assumption Rally would definitely be an extreme example, so I do not doubt you are right. The cars spend as much time in the air as they do on the ground. I would image the loading on the springs is very high and the spring not optimally design for the loading conditions. As such you could probably expect significant material deformation over the duration of stage.

Sorry Al, I have to disagree - though I accept in stock it is insignificatn - but a spring can EASILY soften by 10% over it's first inch of travel as it "wears".

and the same is true of anti-roll ( aka sway ) bars though to a lsesor extent UNLESS runnign REAL stiff bars - because they are subjected to less movement over a greater length and hence less metal realignment due to flexing.

Again, I was assuming street use and a properly sized and loaded component. Also, I probably assumed that it was obvious to everyone else that if you ‘under design’ a component it can easily be permanently deformed.