Flat Ride: what the heck is it?

[slater]

i've been wanting to post about this for a while.

what is Flat Ride?
"Flat Ride" is not a new concept by any means - ZHPs/ZSPs came with it from the factory - and it is a means to a nice, 'harmonized' ride, where the front and rear suspension frequencies work together to cancel out bucking and pitching of the suspension. in our case, these frequencies were determined and selected by BMW; not all manufacturers seem to care about this. this is why stock springs and nice dampers really work well for these cars.

why should you care?
the obvious benefit is a smooth ride, but further benefits are: increased control, and greater comfort - think about how much your body is affected by a poorly-riding/bucking/pitching car - well, you probably haven't thought about it, but hopefully now you will. :) it can affect your mood, too.

why am i being a jerk and posting about this?
for lack of a less clichéd term... i care. i found out about this after researching why my bilstein PSS coilovers were so... weird. the car was bobbing in the front, and i could not figure out why. and my research lead me to shaikh @ FCM (Fat Cat Motorsport), who is the author of the videos i've included below (he cares too). but back to my issue - i found out that the bilstein PSS for my car didn't have flat ride. the rear springs were way too soft. and a lot of aftermarket spring manufacturers (i'm going to pick on H&R here because i'm 99% sure they provided the springs to bilstein for the PSS kits) are creating lowering spring sets without flat ride; no wonder they usually ride like crap! aftermarket coilover manufacturers do the same (i will admit that the MFactory coilovers of recent memory were designed with correct F/R frequencies in mind).

so?
i just wanted to put this out here. hopefully folks use it and benefit from it. i am currently rebuilding my bilstein PSS coilovers into a linear-spring, flat ride setup. i'm pumped to see how they do and i will definitely post here about it.


if you're still reading, awesome. here's more info to nerd out on - bump stop tuning, sway bars, etc:

but first... a funny video from shaikh:


https://www.youtube.com/watch?v=NKkK2_ptc2w


and now... Flat Ride description, bump stop tuning, etc... total nerdfest:


https://www.youtube.com/watch?v=Zpax2pMDGdw&t=79s


EDIT: more reading... flat ride comments from an S2000 owner:

https://forum.miata.net/vb/showpost.php?p=8924466&postcount=28


:cheers

[Oli77]

This is masterful neardyness and quite eloquent! I understand very little about suspension dynamics and kinetics but this is making sense, specially the first video.

Its deep thoughts.

Makes a lot of sense in a straight line, when you corner, (second video), I loose it. As we change tires we tweak that! Imagine the redesign when the manufacturers went to harder runflats. Then we switch to regular tires, are we not flat ride anymore?

[BMWCurves]

Thanks for the info, Peter!

It's nice to see your ramblings about "ride comfort" and "spring rates" and "caring" aren't just signs of you losing touch with "reality"

[Will]

There was quite an extensive thread on m3forum: http://www.m3forum.net/m3forum/showthread.php?t=601913

And a M3f member's post on his revalved Bilsteins by Shaikh: http://www.m3forum.net/m3forum/showthread.php?t=534318

[charter21p5]

When you said stock springs and dampers work well,
I would disagree...

Stock dampers are harsh over bumps.

Your post is interesting and makes a lot of sense however Koni FSDs are far superior when compared to stock dampers on our cars.

Everyone that drives my car with the Koni FSDs agrees. The Koni FSDs transform the ZHP into an amazing ride experience.

[ZHPizza]

Hell yeah Peterman I've been perusing the flat ride thread on m3f and am fascinated with the results people are getting from softer springs, a beefy front sway bar, and stock or completely removed rear sway bar.
When you said stock springs and dampers work well,
I would disagree...

Stock dampers are harsh over bumps.

Your post is interesting and makes a lot of sense however Koni FSDs are far superior when compared to stock dampers on our cars.

Everyone that drives my car with the Koni FSDs agrees. The Koni FSDs transform the ZHP into an amazing ride experience.The OE Sachs are decent , but yeah nothing compares to the ride of FSDs. Peterman put them on his X3 so he knows how awesome they are.

[slater]

When you said stock springs and dampers work well,
I would disagree...

Stock dampers are harsh over bumps.

Your post is interesting and makes a lot of sense however Koni FSDs are far superior when compared to stock dampers on our cars.

well, duh. i was meaning in comparison to aftermarket coilover options (BC, etc). but i probably didn't specify that. whoops.



Hell yeah Peterman I've been perusing the flat ride thread on m3f and am fascinated with the results people are getting from softer springs, a beefy front sway bar, and stock or completely removed rear sway bar. The OE Sachs are decent , but yeah nothing compares to the ride of FSDs. Peterman put them on his X3 so he knows how awesome they are.

yep, they turned a shitty-riding 'car' into a tolerable one. and that is with eibach pro-kits (which helped). i will definitely be putting a set on the Golf when the time comes.

are you going to get an M3 front swaybar for The Red Rocket?

[ZHPizza]

are you going to get an M3 front swaybar for The Red Rocket?Already got a Z4M front sway bar and xi rear. I did notice that it was more difficult to maintain traction out of a turn after adding the rear bar, but I liked it [emoji48]

[slater]

Already got a Z4M front sway bar and xi rear. I did notice that it was more difficult to maintain traction out of a turn after adding the rear bar, but I liked it [emoji48]

get that LSD, yo!