: What... exactly... do the coil springs in a magnaride rear end do?



Dead_Cow
08-16-10, 03:33 PM
When my compressor went, the car sat so low to the ground, the rear tires had massive wear. As in... I had to replace them (yeah, I was lax in replacing it). So, if the coils aren't for ride height as they are in most cars, what exactly are they for and when should I replace them? I have 115k on my 2006 STS4. Ideas hints and input is welcome.

CadillacSTS42005
08-16-10, 08:17 PM
They are for rebound on ride control
And FYI you have rear air ride shocks not Magnetic Ride, that only refers to the front struts.

Dead_Cow
08-16-10, 10:51 PM
They are for rebound on ride control
And FYI you have rear air ride shocks not Magnetic Ride, that only refers to the front struts.Well, I know the rear is airbags... hence my comment about the compressor? It would seem to me that the airbags would be for rebound since they are taking the place o the shocks. Since the car sat so low w/out the airbags on it would seem the coils are tired and should be replaced. I don't know if this is true, though. If the coils are for rebound only, then how would I know when they need to be replaced?

SlickCityStan
08-16-10, 11:07 PM
They are for rebound on ride control
And FYI you have rear air ride shocks not Magnetic Ride, that only refers to the front struts.MRC is on all four corners and STS front suspension uses shocks not struts.

CadillacSTS42005
08-17-10, 08:46 AM
^ by far the worst information
The front suspension is Magneto Ride Technology also known as Magnaride (RPO F55) it uses a fluid that is magnetically charge and when active it hardens to a near plastic like state.
The front supension is infact Magnetic Ride while the rear is Air Ride shocks.

CadillacSTS42005
08-17-10, 08:52 AM
"Magnetic Ride Control is made possible by the development of magneto-rheological (MR) fluid located inside the monotube strut dampers. The fluid is a suspension of magnetically soft, tiny iron particles in a synthetic hydrocarbon-based solution. The fluid's consistency can be manipulated through the precise application of electronic current, resulting in continuously variable, real-time damping. In fact, the development of MR fluid is so significant that medical researchers have adapted it for use in high-tech prosthetic devices, such artificial knees."

You tell me where that exists within the rear air shocks on the STS.

Dead_Cow
08-17-10, 10:43 AM
MRC is on all four corners and STS front suspension uses shocks not struts.
Um, no. :annoyed:

Dead_Cow
08-17-10, 10:44 AM
Still, can anyone tell me why the car sat so low w/ no air in the bags? Is this normal, or are the springs worn beyond their life?

next2pool
08-17-10, 03:09 PM
The rear springs provide the primary load carrying capability and the airbags provide a margin of extra load capacity so it can adjust for additional load. All airbag assisted vehicles sit a bit low without the airbags inflated. Consider it a 80% spring/20% airbag load distribution--that's just an example, not an actual number. Shock absobers themselves have no affect whatsoever on ride height--they only provide damping. And yes, the STS has separate shock absdorbers, not struts.

Dead_Cow
08-17-10, 03:15 PM
Well, this rear of this car was ON THE GROUND when the airbags wouldn't inflate. The wheels looked like this: //----\\

I definitely know there are absorbers in the front. I just hope I never have to replace them. They are ridiculously expensive.

next2pool
08-17-10, 03:32 PM
Well, this rear of this car was ON THE GROUND when the airbags wouldn't inflate. The wheels looked like this: //----\\

I definitely know there are absorbers in the front. I just hope I never have to replace them. They are ridiculously expensive.

Yup--the rear suspension has a very sharp camber curve as it gets into jounce--the rear wheels will move into negative camber very quickly as it sits lower. And yes, those magnaride shocks are very expensive. It's nice feature, but when it's time to replace, it throws an whole new light on it.

Dead_Cow
08-17-10, 03:42 PM
So what am I missing, then? If the rear springs are (approximately) supposed to take up 80% of the load, it would seem that without the bags, I should ride @ 80% height, no?

next2pool
08-17-10, 08:13 PM
Remember I used 80% as an example not the actual number since I don't know what it is for the STS. Every GM car has it's own ratio of base spring contribution and assist "spring" contribution from the self leveling system. Apparently the STS relies on a substantial contribution from the self leveling part (for those with the airbags). That's all a system design consideration.

EChas3
08-17-10, 10:43 PM
I recall a thread concerning two different rear load leveling systems that I thought depended upon whether the STS had MRC. That would imply all four shocks have the magnodynamic dampening shock fluid. (most recently touted by Honda). :)

I know my front shocks have control wiring; i.e. they are part of MRC. Is there concensus from members that the rears are not part of that system?

Any longer term members remember the thread I reference?

next2pool
08-18-10, 10:44 AM
I recall a thread concerning two different rear load leveling systems that I thought depended upon whether the STS had MRC. That would imply all four shocks have the magnodynamic dampening shock fluid. (most recently touted by Honda). :)

I know my front shocks have control wiring; i.e. they are part of MRC. Is there concensus from members that the rears are not part of that system?

Any longer term members remember the thread I reference?

If you have magnaride, all 4 shocks are part of the system. The reason magnaride uses airbags for leveling is that the Nivomat self leveling shocks (as used on the base system) are not available in the MRC configuration.

EChas3
08-19-10, 10:33 PM
Thanks for the comment from next2pool. Mind your sunscreen. You're an asset to the forum!

next2pool
08-20-10, 02:18 PM
It's funny you say that--about 3 weeks ago I got heat exhaustion working outside on my motorhome. That's the first time I ever experienced it and wiped me out for almost 2 weeks!! Thanks for the complement tho :)
Thanks for the comment from next2pool. Mind your sunscreen. You're an asset to the forum!

It's funny you say that--about 3 weeks ago I got heat exhaustion working outside on my motorhome. That's the first time I ever experienced it and wiped me out for almost 2 weeks!! Thanks for the compliment tho :)[