[Fraggy]

Is there any reason to believe that Koni FSD will improve the ride comfort with RFTs?

Part of me thinks NO, the damn things can never be smoothed out.

The other part of me thinks YES, that the dual damping will soften out the sharp jabs and shudders from the RFTs.

Whats your take on this? And yes, the car will be lowered, most likely on H&R.

[montreal_bimmer]

I would only go with the FSD's if you want to go with the Eibach Pro kit or H&R sport springs, they're stiffer than the stock shocks, but stock sport shocks will do the job too.

as far as improve ride comfort... i dont know, you'll have to find someone riding on that setup

[Orb]

This is what I got directly from Koni Europe:

The FSD 2100 4036 are tuned for sport and non sport suspension

The FSD 2150 4036 are specific tuned for the Eibach springs so the dampening rates are not the same as 2100 4036 shocks. This was sole purpose of the release of this package.

The dampeners can not work past 1.25" drop from the non sport suspension. If you are riding even slightly on the bump stops with this shock during normal condition they dampening will go full soft in compression and rebound so it feel like you have no shocks at all.

To answer your question using FSD 2100 4036 with HR spring you will be under dampened since the spring rate is greater than 20% over the sport suspension. The only alternitive for any drop in the Koni FSD + Eibach combo.

I never understood the fascination with HR spring as Eibach is a much more mature company and tier 1 supplier. The manufacturing quality of the HR and Eibach is going to be identical.

Originally Posted by Fraggy

Is there any reason to believe that Koni FSD will improve the ride comfort with RFTs?

Part of me thinks NO, the damn things can never be smoothed out.

The other part of me thinks YES, that the dual damping will soften out the sharp jabs and shudders from the RFTs.

Whats your take on this? And yes, the car will be lowered, most likely on H&R.

[Fraggy]

Hmmmm, Im so confused now.

Thanks for the responses. Any others?

[HighlandPete]

Originally Posted by Fraggy

Hmmmm, Im so confused now.

Thanks for the responses. Any others?

New here... but hope my experience can help.

I’m about to fit the Koni FSD’s (2100 4036) to my E91 330d touring, running standard (non sport) suspension and 17” wheel sets. Got them here in my office ready for fitting.

I’ve been viewing the FSD threads and glean that most users are after sportier/ lowered combinations. This particular thread “FSD’s and RFT’s”… is MY ISSUE. I’m fitting these purely to improve the ride quality, to try and rid the car of some of the awful issues caused by the RFTs. Not after lowering or the traditional ‘sport type’ package.

Driving in the Scottish Highlands means sport suspension on RFT’s is a terrible ride. My typical roads are really pushing the envelope for RFT technology. Been in discussion with both BMW and Bridgestone and this ‘extreme envelope’ is confirmed. I’ve had all the RFT issues…. Strange tyre (Bridgestone Potenza) wear, severe ‘heel and toe’ plus the ‘stepping’. A weird form of tram lining, bump steer, tug steer, skitter, severe crashing and vibration into the car. Causing rattles, creaking and groaning. Really a ‘Go Kart’ drive, on anything but the best road surfaces.

I’ve experimented with a different wheel set, running conventional rubber, Goodyear F1’s. This has dramatically changed the car, but not a total success. There is still a suspension issue. The suspension changes quite a lot with temperatures. Haven’t got to the bottom of this yet, but believe the rubber content needed to help the RFT’s work, makes it more susceptible to this characteristic. Problem is when warm, the suspension and primary ride feels a bit soft on normal tyres. But the secondary ride is still too harsh at lower ambient temperatures, when the primary ride is about right.

Therefore the reason for the FSD’s. Should help the handing, stiffen it a bit while allowing the better ride. Will also give me a chance to try the RFT’s again and get some comparison data. I’m also keen to try the latest generation RFT Bridgestone Potenza rubber.

It will be a couple of weeks before I fit the Koni FSDs, as the car is going to the garage for a climate control problem. And we may be trying 18" RFTs as there is experience being gathered over here of the 17” giving the worst driving dynamics, why? No one seems to know yet.

I’ve been scanning the forums for this very issue of fitting FSD’s, purely for improving the RFT issues, but most who have changed seem to go further, and/or are seeing the FSD’s as part of a sport package. So simple feed back is minimal, or biased by the perceived benefits, or not, to other car dynamics.

BTW, just last week I tried a 330d E92 coupe, standard suspension on 18” 8/8.5” wheel set on Bridgestone Potenza RFTs, and the ride quality has moved on dramatically. I go as far as to say it would be hard to judge if the car was on RFTs. No crashing, no strange steering or handling issues. Car had covered 5,500 miles and temperature about 6 – 8 degrees centigrade. Gave me confidence that BMW are getting it right, but no real help to our cars.

I shall be back with my views, once fitted and tested.

Cheers

Highland Pete

[Fraggy]

Thanks man, keep up posted.

[HighlandPete]

I've fitted the FSD's and reported my first thoughts in:
http://www.e90post.com/forums/showthread.php?t=53814

I'll be trying the RFT's in April, to see if they work better with FSD's.

HighlandPete