[black 335xi]

Is anyone using the Eibach springs with Bilstein HD struts/shocks, rather than the sport version?

Initially, I just upgraded to the Bilstein HD's, without springs, and the ride was much improved, though it still had the ride height of an SUV-

Added the Eibach springs (pro-kit) and continued to use the Bilstein HD dampers. My understanding is that the HD's and the sports are valved the same, and I know that some people are using this combo. Ride is very firm in my opinion, but not necessarily harsh.

Here's my question- With the shorter springs, am I outside the optimal "travel" of the Bilstein HD's or am I OK ? Would the ride be better with the Sports instead? Any pitfalls for continuing to run the HD's instead of Sports. Anyone with an opinion based on fact/experience please chime in.

[AWD Addict]

the Bilstein HDs are designed for increased performance but at the stock spring size and ride height.

You should pair the HDs with stock springs, or use your lowering springs with the Sports.

I think you're riding with the piston under constant compression, and outside of the optimal travel distance. As other's have reported on this forum, you can expect to have problems on larger bumps when the piston maxes out it's travel distance, and you have no dampening ability left. I'd also expect some reduction in useful life of the strut/shocks, but depending on your road and driving conditions, it's very hard to say how much shorter.

Bottom line, the piston is 1.25" or so more compressed than it was designed for, all the time. I suspect that's why you feel this setup as stiff, where if correctly matched up, it's pretty compliant and comfortable. You're into a more heavily valved section of the piston travel, which is only typically experienced on a decent enough sized bump to compress the piston that far rather than regular relatively flatter driving. Small bumps, cracks and freeze joints are probably feeling a bit rougher than they should.

Take a look at this thread.

http://www.e90post.com/forums/showthread.php?t=660404

[black 335xi]

Originally Posted by AWD Addict

the Bilstein HDs are designed for increased performance but at the stock spring size and ride height.

You should pair the HDs with stock springs, or use your lowering springs with the Sports.

I think you're riding with the piston under constant compression, and outside of the optimal travel distance. As other's have reported on this forum, you can expect to have problems on larger bumps when the piston maxes out it's travel distance, and you have no dampening ability left. I'd also expect some reduction in useful life of the strut/shocks, but depending on your road and driving conditions, it's very hard to say how much shorter.

Bottom line, the piston is 1.25" or so more compressed than it was designed for, all the time. I suspect that's why you feel this setup as stiff, where if correctly matched up, it's pretty compliant and comfortable. You're into a more heavily valved section of the piston travel, which is only typically experienced on a decent enough sized bump to compress the piston that far rather than regular relatively flatter driving. Small bumps, cracks and freeze joints are probably feeling a bit rougher than they should.

Take a look at this thread.

http://www.e90post.com/forums/showthread.php?t=660404

Hmmm....yes, what you're saying was on my mind as well. On another thread, a fellow was using HD's and an Eibach pro-kit and justified the choice by saying that the valving between the two was the same, and that the shock bodies were the same length- only the shaft on the HD's was longer, and that the only difference was that the Sports would keep the springs from coming off their perch with really short springs. I wondered about being in a different phase of the damping all the time as well. Are you running the Bilstein sports?

[AWD Addict]

I am.