Expose’: Actually no huge surprise here, Renntech doesn't make their own springs. But these highly regarded, and supposedly ‘C32-specific’ Renntech springs are just poorly-repainted standard W203 Eibach’s. Buy the Eibachs from some place like Tirerack and enjoy for ½ the price. Save your mod money for something else.

But this raises some new questions: Renntech C32 spring reviews = 100% positive, Eibach reviews are mixed, (but mostly from standard C-class owners). So were the W203ers that didn’t like Eibach smoking something different? Or do they really perform differently on stock W203 vs C32?

 

Thanks for taking pictures. For me it was no surprise there. I mentioned that back almost four years ago on C32life. No one wanted to believe.


My guess on reviews, good feedback has to do with an old "money factor" - if it is expensive it must be good.

 

I'd like to hear what Renntech has to say...

 

I thought that was a known fact? Guess not.

 

They perform differently on every different chassis and with every different complete set of suspension components and design on every different car.

Renntech was wise, I believe, to do what most other tuners and manufacturers do - seek out the best engineered and manufactured products out there to sell to their customers. Nothng unusual or inherently dishonest or sub-par about that.... I was particularly pleased when I heard last year that they were starting to carry a bunch of MKB's componentry.

Brembo, and Bilstein, and Eibach - to name a few - supply their components to a gazillion different manufacturers and tuners.

Its all good.

 

made by same brand, but diffferent compression ratios, so you get better handling and feedback wit the renntechs...

 

I remember you said it. lol

they are different compression ratio even though they look the same. i just parked next to someone with Eibach springs on a C320. The drop is not the same because of the compression ratio.

since we're on this topic, AMG suspension and Brabus suspension are both made by SACHS.

 

Frank, you must be referring to the C32 suspension because my C55 springs have Eibach written all over them. Or you could have been referring to the shocks/struts.

 

C32 and C55 could be different than. MB/AMG probably just use whichever supplier that provides them parts at the time. I know the C32 shocks are made by Sachs and Brabus suspension are made by Sachs to their spec.

but anywayz, even though the springs are made by same company, but they're all designed with different compression rate.

 

OK, so now I'm curious. How can two springs made by the same mgf. out of the same dia. stock, same # of coils and same length have different compression rates? The only thing that I can think would make a difference would be if the metals in the two were of a different hardness. But that could be checked as well at almost any tool and die shop that can read Rockwell Hardness. Renntech could have their rockwell hardness altered by Eibach I guess......or they could have some kid in the back with a torch.......

 

I know that they do engineer the metals as well as the rest of the factors in a spring....

 

The only way to know for sure it to measure the spring rates and compare. RENNtech has never stated that they wind there own springs in their own factory. There are only a few spring winders available to all tuners and if Eibach winds their springs, they selected a reputable company. It is not unusual for a tuner to have a dozen or more "identical looking" springs wound at different spring rates for testing purposes. The type of metal does matter, as well as the thickness of the stock and how they are wound to produce a linear or progressive nature when compressed as measured at each inch increment of compression. It is really difficult to tell if one spring is equal or different than the other just by a visual inspeciton. Here is a pic of two equal length springs that appear to be very similar. The red is an Eibach at 500 lb/in, the green a Racing Dynamics at 325 lb/in wound by Eibach Germany at that time I was told as these came from overseas. If they were both painted black and not labled, you could not tell the difference, but they made a huge difference on the front of my car.

 

"Rockwell Hardness" sounds like the pen-name of an author of check-out counter romance novels.

 

Here is the problem - they sell the same components that are sold by major manufacturers through their normal retail outlets, painted in their own color, except they claim that they have developed them and therefore they can charge twice as much.

Sorry, in my book it is called - DECEIPT. Not being WISE.

P.S. They sold MKB products under their own name for twice the price one could get from Europe - going back a BIG number of years.

 

Someone metioned earlier that Sache shocks that are on the C32 are also sold by Brabus. That is true and Brabus will not deny it, I questioned it and they confirmed it. But when it comes to the SPRINGS; Eibach or Renntech, if they are the same, I've been told that you (after 6 months) will need to replace the Sache shock.

What's the point! Since you are paying for the labor, just do it all at once, either the Blistins, KW2 or H&N cup kit or coilovers..

Am I right?

 

Correct! If you are replacing springs, replace shocks at the same time.

 

Interesting conversation. Which begs the question; what is the difference between the Carlsson RS and the Bilstein PSS-9? Same spring rate, same shock valving? We won't know until someone does some testing. I tried, but no one was willing to ship me their parts for comparison. We do know with some certainty, that Eibach and H&R are the two springs manufacturers. It is thought that Eibach provides Carlsson with springs, and H&R for the Bilsteins, which makes sense due to their many joint ventures. As for the shocks, both are made by Bilstein. Is the valving the same? I would bet not as Carlsson would want a unique product to Bilstein, and revalving them to a different spec is easily done when ordering their run. Is there a huge difference, I am sure not. Is there 50 lb/in in spring rate variance, probably. Is there +/- 20 in compression/rebound rates, probably. Are they very similar, yes. Is one better than the other, no. Why is the Carlsson more money? Because it is an exclusive brand to MB, whereas Bisltein is generic. Would Carlsson spend more time tuning their suspension? I believe so since they want to market a usable suspension system that they can be proud to sell. Would Bilstein spend as much time tuning the PSS-9 on such a limited sales volume for MB, when their bread and butter is Porsche and BMW? I don't think so. Which came first; the PSS-9 or the Carlsson RS? Interesting question, and it is quite possible that Carlsson went to Bilstein to make their suspension system, and Bilstein in return got to offer it within their own line. A win win business deal. Should Carlsson get more money for their coilovers? Yes. Why? They sell less units per year than Bilstein and they actually tested the product on the car. Some tuners don't even test their product but calculate what should work and release it to market. Why does your local small store charge more for product than Costco? What does all this mean? The Superbowl is over...

 

Yes, indeed.......................

And tomorrow it is NOT going to rain in SoCal.........



On a more serious note:

Assume the worse, hope for the best and expect mediocrity - unless done by oneself.

 

Vadim- I was a C32 owner at the time and I can tell you this: the Carlsson's came almost a whole year (or more?) later than the PSS9's and were a vast improvement over the Bilstein system (not that the Bilstein's were any slouch). Carlsson really dialed their system in. If I remember right, they also had more adjustability, and were easier to adjust.

If you had a C32 and you took it to the track - or just went 'canyon carving' often - the Bilstein PSS9 Coilovers were the way to go -- until the Carlssons came out.

 

As far as I know, Carlsson is revalved Bilstein PSS9 system. Externally they should be the same. The only true way to find out is to compare them back to back on the same car, on the same track.

 

I knew a whole bunch of people personally, and went to the track with them many times and did exactly that. The Bilsteins were great - don't get me wrong...but the Carlssons were just that much better. And we all agreed. Same people. Same cars. Same tracks.

 

Also remember that Carlsson originally created the RS suspension for their CLK. I just happens to fit the other W203 cars. And I suspect that it will feel a little different on each variation of this platform given the different weights front and back. Bilstein was marketing the W203 chassis as a whole in europe with the CLK fitment as a bonus. Regardless, the RS is not a smooth ride on the streets and must be tolorated. I have driven a few BMW's with the PSS-9's and was not impressed. Most owners change out the springs and some revalve the dampers. Vadim is correct, the RS is identical to the PSS-9 in looks, fitment and adjustability.

 

Was a post deleted within this thread today?

 

Maybe Renntech's Pulley kit is really an evosport ? LOL

 

NOT! and that is confirmed by numerous threads and posts within this forum. No need to spread more rumors.