[Tallest]

Just curious - do they have better testing facilities to design suspension better than OEM? I mean BMW spends millions of dollars finetuning its setups and it goes through hundreds thousands of miles of testing before the product is ready. What kind of research goes behind KW, H&R, Koni, Bilstein, etc?

I'm looking to be convinced why should I stick with non OEM suspension for my 50000 dollar car. I think BMW did get it wrong with RFT tyres though, so I am open to all arguments here.

[branabolic]

stock suspension is all about compromise. not everyone buying this car wants it to handle superbly and is willing to sacrifice some ride comfort. aftermarket companies have to opportunity to market to a more focused group of buyers thus allowing them to make a more performance oriented system

[KL2DC]

Originally Posted by branabolic

stock suspension is all about compromise. not everyone buying this car wants it to handle superbly and is willing to sacrifice some ride comfort. aftermarket companies have to opportunity to market to a more focused group of buyers thus allowing them to make a more performance oriented system

100%

[mike-y]

Better is subjective, based on what your needs for the car are. the OEM suspension is a good mix of comfort and performance. And with it being a mass produced part for hundreds of thousands of cars, BMW needs to be able to have the parts made economically, so they can turn a profit. So in most cases, an OEM suspension is decent, but may not have the features you can get with a nice aftermarket setup.

Aftermarket setups can give you stiffer springs for better cornering performance, height adjustability, and damping adjustability. So if any of those things are important to you, and you can sacrifice a little comfort, and/or ride height, then that's why you would switch. Otherwise, if you are happy with the stock suspension, then stick with it.


Edit: branabolic pretty much summed it up.

[scottp999]

A happy medium looks to be the BMW Performance Suspension, mentioned by Tischer BMW in the sponsors area.

[The Cleaner]

"Better" depends on what you are doing. For the street most aftermarket stuff is overkill. For example lowering a street car has largely negative results for a daily driver. Plenty of people will disagree but it's true. If a lowered car with super stiff suspension was desirable car manufacturer would build them that way.

[SV Concepts]

Originally Posted by branabolic

stock suspension is all about compromise. not everyone buying this car wants it to handle superbly and is willing to sacrifice some ride comfort. aftermarket companies have to opportunity to market to a more focused group of buyers thus allowing them to make a more performance oriented system

Couldn't have said it better myself.
But to clarify... BMW OE is about "good" handling and "good" comfort, whereas aftermarket can be adjusted to be "good" handling and "great" comfort, "great" handling and "fair" comfort, or any combination thereof... BMW aims for the baseline of what consumers will want, and hits it right on the mark.

Now, if you buy a 997 GT3 RS... OEM is going to be roughly as good at handling as any aftermarket setup (well, almost...) because Porsche designs it for a specific purpose

Your 3 series wasn't designed for the track. But you can fix that
JL

[stressdoc]

Bilstein, Boge, et al make the dampers for BMWs. Aftermarket products are designed for more specific needs. You are correct that BMW burns a ton of cadcam & track time designing the OEM systems, and those of us that play around with swapping out parts can't hope to approach the level of tuning that BMW can. But that doesn't stop us.

[Tallest]

yeah, i mean i dont want to bash aftermarket, im genuinely interested if the aftermarket guys really do deliver better products or not.

I am aware that KONI for example has huge testing facilities and read article about their FSD system that left me pretty convinced they have the tradition and knowledge, do talk to manufactueres a lot (sponsoring McLaren F1 I guess is nice bonus too)--- so I'm quite sure they know what they are doing.

and then there are posts like this one that make you wonder if the aftermarket guys really do know what they're doing... :S http://www.e90post.com/forums/showthread.php?t=224928

[branabolic]

^haha all these threads about clunking noises are the only thing scaring me from pulling the trigger on some coilovers right now. well that and the fact that i can't find a shop to install them for less than $600!