540i: Bone-jarring ride

[RSK540iA]

Every since buying my E34 540i last year I've had to live with a hard and uncomfortable ride. The control arms and shocks have been replaced. Last month I replaced the tyres. I've now dropped the tyre pressures to 2.1/2.2... not much improvement. Any ideas? Thanks!

[Macv]

Springs? Bumpstops?

Give us some specs on things. Is it basically stock? Lowered suspension?

[BMWDriver]

What wheels are on ? Low profiles are absolutely rougher than 15 or 16 inch wheels.

[CharlesAFerg]

I've got a stiff setup with my springs, shocks and polyeurathane everything, replaced al the arms and links... etc
I'd hardly call it bone jarring, you must have destroyed bump stops, it made a nice bang in my old stock trash.

They were 1/3rd of the original length, lol - terrible.

[Rick L]

I couldn't feel the difference in ride comfort between 15" to 17" when I upgraded. But once I upgraded the suspension with Koni sports adjustable and Ebach springs then I noticed all the imperfections of the roads. I have my Koni at half turn. I prefer stiffer ride.


What wheels are on ? Low profiles are absolutely rougher than 15 or 16 inch wheels.

[RSK540iA]

Thanks guys!

The suspension is stock standard, as are the rims (alloy) and tyres (Bridgestone 225/60 x VR15 ER300). I just fitted Sachs touring shocks to the front, the bump stops are apparently inside the shocks so they're brand new. The ride height is also good. I suspect PU bushes were fitted when the control arm bushes were replaced. They absorb very little, if anything at all. Every little undulation is transferred directly to the chassis. My 1985 MB 230E gives me a better ride.

I spoke to another E34 540i owner yesterday. His ride is silky smooth.

[CharlesAFerg]

bumpstops in the front shocks...? What? Not on my E34, but a touring I wouldn't know.


I couldn't feel the difference in ride comfort between 15" to 17" when I upgraded. But once I upgraded the suspension with Koni sports adjustable and Ebach springs then I noticed all the imperfections of the roads. I have my Koni at half turn. I prefer stiffer ride.

I totally noticed a difference with my style-5s, I'm surprised you didn't.

[Tiger]

I had same problem as you... until I changed the sway bar links and then everything is silky smooth again.

[Rick L]

Maybe the difference in tires? I have Falken Azenis on BMW 17" BBS 42 with 235 (at 34 psi) fronts and 255 (at 38 psi) rears. Even with wider 255 rears, I couldn't really noticed the difference in ride comfort (from stock 15" 225). But definitely noticed the difference in performance wise. :D




I totally noticed a difference with my style-5s, I'm surprised you didn't.

[RSK540iA]

Sway bar, would that be the same as 'anti-roll' or 'stabilizer' bar? The car's going in on Tuesday, I'll ask them to check every single front suspension component and give me a full report.

[Tiger]

Yes, that's the same thing... just change them out... easy cheap part to change.

[t_marat]

I have the same issue. Suspension let's through everything from the road. Wasn't like this 2 months ago. I started to think if the bushings are gone, as there is also a vibration (vertical shimmy) at about 100km/h. But the bushings look OK. They were installed last february, the green 750 ones (ordered from BMA). Could the stabilizer bar also cause shimmy?

[Tiger]

You need to check everything... steering arms... all of them

Then when is the last time you had your wheel balanced?

Is the wheel center hole designed for E39? If it is aftermarket wheels or upgraded BMW wheels? If so, you need center shims to take up the space.

Stabilizer bar links are overlooked majority of time and when they are worn out... car feels mushy out of control in a diagonal way...

Rear dogbones are also overlooked too... they also cause odd steering responses.

Once all this is diagnosed, it should be fixed.

[Russell]

new rear sway bar links made a big difference in ride comfort. I was surprised.

[Tiger]

Isn't It? That little dinky skinny sway bar eh? Couldn't believe it either... did two cars and both same story... way more stable and rides alot better. Now I gotta swap out those dogbones... hard to do when it is freezing out.

I also gotta swap out the entire steering stuff.