mitchntx

iTrader: (14)

I would agree.

Don't buy a cheap part expecting it to work and last like a better engineered and designed part.

The better parts typically are more expensive.

The unfortunate thing is, folks buy according to their wallet, instead of application.

Guilty as charged ...

DrkPhx

iTrader: (15)

Well said. Road Racing will bring out the weak link of a suspension, even if it's an aftermarket piece. Buy parts specifically designed for the application.

mitchntx

iTrader: (14)

Don't misunderstand me ...

If you don't think that aggressive or semi-aggressive street driving puts equal forces as when on a road course, then you will be in for a big suprise, someday.

DriveATransAm

i drove my car on a road track a lot harder than i would ever see on the street i thought my tires were gonna come off my rims

mitchntx

iTrader: (14)

That track was propbably relatively smooth, never shocking or pounding the suspension, like a pothole, a 2x4 or a speed bump ... or even the manuever to avoid them ...

Caswell

Two things - one comment, one question.

First, as someone who works as an engineer at GM's proving grounds, I can tell you stuff is tested way beyond what an average car will see on the street. There are countless tracks and roads out there designed to do nothing but beat the tar out of cars in every way imaginable. I'm not even in development (yet), but you should see what I get to do to some of those cars as part of my work as an engineer - and that's coming from someone with a circle track and road course karting background.

Secondly, I'm not entirely convinced that these failures wouldn't happen with any poly/poly bushing rear suspension piece. The way our rear axles move, smooth pavement or not, something has to give. When you take out the rubber bushings and slap rock hard poly in there, either the sheet metal on the car has to give or the metal surrounding the bushing has to. Going back to my experience in the OEM world, my money's on the aftermarket part.

SSixspeed

I'm not sure I agree with the second part.

If something must move, even rod ends wouldn't do the trick. And then it wouldn't just be on the panhard, it would include all suspension components that are replaced with rod ends.

trackbird

iTrader: (4)

This is a repeat of one of my earlier posts (in case it got "lost" in all the replies....)

I agree completely with this statement:

After a "period of time" you will either:

1.Destroy the bushing.
2.Break the housing the bushing is in.
3.Tear the sheetmetal that the control arm mounts to.
4.Break the control arm bolt (fatigue cycles).

The suspension is designed to move in various planes of motion, if something restricts this motion (other than the bumpstops or the limits of shock travel), that part will be subjected to tremendous loads. The only way to help this situation is to reduce those loads. If you don't take steps to reduce the loads, the suspension will eventually do it for you (something will break). I think we are starting to see this first hand. Everything has a fatigue life, we are just starting to see what that lifespan actually is.

However, I don't agree with this statement:

By "move" he is not talking about slop or "give" in a front to rear direction. He is saying that the parts must be free to rotate as the manufacturer designed it to do. Rubber has a natural "give", but it gives in directions that it shouldn't. Heim joints allow us to make the suspension "give" only in the directions that we are asking it to move in. We can be very solid front to rear and yet offer almost no resistance to rotational motion and the correct articulation of the rear suspension.

It's getting late and I hope this answer makes sense....I'll re-read it tomorrow.

Keep the shiny side up!

mitchntx

iTrader: (14)

I think sometimes we forget good ole momentum.

If something is rock solid, then forces have to go beyond sheer of the weakest part.

If something has slop, there are still the same forces applied, however there is now shock involved.

With bushings deflecting and with back and forth forces applied, like during a spin, the shock forces have to be tremendous.

trackbird

iTrader: (4)

Good point Mitch. I was only thinking about good old fashion "twisting it off"....the shock loads are an additional concern that I skipped. I was only considering new parts and new bushings...

Caswell

Thanks for clarifying what I was trying to say Trackbird. I think a lot of poly/ploy fans forget the fact that unless your car is doing nothing but going in a straight line on level pavement (i.e. a drag strip) that there are twisting forces on bushings of both the LCA's and the PHB.

I totally agree with your comments on rod ends. As someone who grew up around circle tracks and midgets/sprint cars, I know how expensive a good rod end is. The only rod ends I'd trust in a hard-driven car are more expensive than I'd care to spend on my street car. I'm sure I don't have to tell you how expensive good rod ends are though...

trackbird

iTrader: (4)

I'm just glad to see that my answer made sense. I'm not sure I was awake at the time.....

mitchntx

iTrader: (14)

COnsider for a moment poly on one end and a rod on the opposite.

The only binding from twist would occur if the articulation was so severe that the rod end "housing" came in contact with the mount, correct?

trackbird

iTrader: (4)

Correct.

mbraun

iTrader: (3)

Sam Stranos makes a very nice PHB. It is chromoly steel so it is light yet strong. It has adjustable heim joints on each end. I have this in my car and hit the road course fun days several times a year. It is very solid and I bought it new for $169.00
.

Weezzer

Geesh, why revive an almost 4 year old thread...

BIG_MIKE2005

iTrader: (116)

People never look at the dates. I'm guessing he did a search & just replied without reading the date.