stallion150

Hey all---pardon my ignorance, but on the way to changing my suspension setup on my 2009 C350 (I want to make it more stiff, and minimize body roll), what would I start out doing? Thanks!

Derspeed

Are you lowering it? You can have a stiffer suspension any height with H&R coilsovers. Bilstein coilovers will allow you adjust the stiffness too. If you don't mind going about .50" to .75" lower, you can install Eibach or H&R springs. H&R Super Sports will make it even lower. Finally, you can probably get away with Bistein HD Shocks with your OE springs. They have been known to raise other cars a bit.

http://www.hrsprings.com/

http://www.bilsteinus.com/cart/ymm.p...el=C350&zenid=

http://www.eibach.com/cgi-bin/start....ach/index.html

stallion150

Thanks a lot! I probably don't need to lower the car, but i thought stiffer suspension would clear some of the washiness I feel over the car during hard turns and bumps. Is there any that you personally recommend?

bk.968

You might want to check these as well. Quality stuff with quite some racing experience. Fully adjustable, so you'll find a road/daily driver setup easily.

http://www.kw-suspension.com/us/

http://www.kw-suspension.com/us/kw_variant_3.php

stallion150

Thanks guys, i'm gonna forward this stuff to my one of my friends who does my aftermarket work on my car

Sportstick

You also could just start with Eibach front and rear anti-sway bars, also from Tire Rack if you want to try this in steps.

stallion150

Thanks guys---the one thing that has left me dissatisfied with my C350 is what I would call body roll. In my definition, its lateral motion in the car over bumps (not up and down like a traditional harsh ride)--sometimes minor, but enough that it irritates me. I hope that putting in the H&R coilovers as well as sway bars will fix this.

Azn_C300

Also front(MB Arts, SMERC, Renntech) and rear(Renntech) strut braces if you wanted to finish it off.

kevink2

If that's what really bugs you, like going at an angled approach over speed bumps, then all the posts about stiffer springs and bars will improve handling (if done right) but will not help you. Smaller ( ie C300 Lux ) or no sway bars will. Keep oem springs. You want to soften roll stiffness at front and rear. To see if this is the right direction, test drive a C300 Lux over those same bumps that cause roll.

Sportstick

You may be right, but we may be getting tripped up by semantics. He first complains about "body roll", which suggests stiffening anti-sway bars. But, he then talks about lateral motion, which could be the rolling motion, or he may mean the sideways hop which occurs during turns on less than smooth surfaces when roll stiffness is high. He does not complain about oversteer, so he's not having lateral motion with the rear wanting to come around. C Class is way too neutral-to-understeer for that. I recall this vividly from early BMW 3 series where your solution was exactly what was needed. Your suggestion about softening stiffness may be right on, but I think we need a further clarification on his objective.

kevink2

yup

stallion150

Hey guys---thanks a lot. It's a difficult thing to describe, but basically what i'm feeling is that when the car goes over uneven pavement, instead of an up and down harsh motion of the car, what I feel is that it feels floaty and I perceive lateral motion of the car. Kind of like when you are on a rollercoaster and your head bangs against the headrests from side to side. The car doesn't feel well planted on the road; i.e. really harsh rides feel very planted, you just feel every bump. In my case, the suspension is soft but it seems to create lateral motion over uneven pavement (almost like a mild skating motion--how skates go across ice)---I have no issues with roll during turns.

Cars I've driven with stiffer suspensions (like BMW's), tend to plow right through uneven pavement--so i feel more motion in the vertical (y axis) rather than horizontal motion (x axis) that I feel now. The horizontal motion is much more bothersome to me.

I hope I've explained better.

Sportstick

I've not tried the following on any car since my 1977 3 series, but based on your comments, which are actually a quite uncommon concern, I would try having the rear sway bar removed, as kevink2 suggested, drive it around and see if the change is directionally correct for you. The ideal solution may be a less stiff bar than stock if having no bar takes it too far for you...perhaps the C300 Luxury spec, if it is unique.

BTW, what tires are you running?

stallion150

**I should also say that switching from 18'' wheels to 17'' wheels made a huge difference in dampening this sensation.

Yeah, i totally get i'm in the minority in noticing this; but unfortunately it makes the car less enjoyable. Thank to you guys for your help.

I'm running 17'' Michelin Pilot HX MXM4 tires.

Sportstick

If changing to a taller (more compliant) profile tire on a 17 (vs 18") wheel helped, kevink2 and my suggestions for a less stiff/no rear bar are more likely correct, for you! (BTW, I am getting stiffer bars from Eibach)!) I would also dump those tires and get some Michelin Primacy, not my taste, but should work very well for you. Compare cornering stability and ride at the following link:

http://www.tirerack.com/tires/survey....jsp?type=GTAS

(To find MXM4, you'll need to look at the bottom of the list!)

stallion150

Thanks guys that makes a lot of sense. What's weird though is when I test drove an M3 and a 335i both with 18'' wheels, I noticed none of this lateral motion over bad roads. Both beamers felt rough over bumps, but felt much more planted on the road than my C350; meaning no side to side motion of the car, just a momentary up and down over bad road. Both have noticeably stiffer suspensions than my C350, but i vastly preferred that type of ride to mine.


Maybe what I feel is due to a combination of the qualities unique to the C350's suspension plus larger tires?

kevink2

When we tried out our C300 4matic vs similar A3 and 3 series BMW's, it was obvious the c300 was more set up for a softer, classier ride. I have 1000's of miles of track circuit experience, and pushed all cars. And the M3 is not even close to a c350.

You didn't verify the speed bump issue I gave, so softer bars may not be the trick ... stiffer shocks, springs, and suspension bushings, or perhaps a BMW.

Or it could be "just get used to it" .