smoothening the ride
 

recently got the following done to my car (230E W124):
replaced front shocks (bilstein HD)
replaced front (r&L) lower control arm bushings
replaced steering dampers
replaced all front sway bar bushings
replaced all rear bushings
replaced all rear ball joints
replaced rear stabilizer arm assembly
replaced all rear coil spring seat

Also, last year I replaced the following:
front lower ball joint
tie rod
center link
idler arm
differential bushings

These are all with the end in view of experiencing the ride-like-new feel to a rather old car (17 Years old), but to no avail. I still hear the usual annoying sound of going through the bumps, feel road imperfections, etc. Am I missing something? I know that the shock mounts, subframe mounts rear shocks have not been touched but according to my mechanic these are all still ok. Would appreciate receiving any inputs on this matter.

by the way, I don't know if this has any bearing but my tires are sized 215/17/50 and springs are stock.

Thanks in advance.

The lower the side wall height on a tire the less flex thus a greater amount of impact is going to be translated to the cabin of the car.

I am assuming your car has 215/50 X 17 tires? Try trading the wheels and tires with another car that has the standard recommended whiles and tires. You can find the recommended tire sizes by looking in the driver's door jam or your owners manual.

Keep us posted,

Haasman

17 inch wheels? That will have a huge affect on ride quality and noise. If you want "like-new" ride quality, you need "like-new" wheels, which are 15 inchers with, I think, 65 series sidewalls.

That said, I'm pretty dissappointed with the noise and rough ride quality of my w124 that I recently purchased. The tire selection will also make a difference. Do some research on quiet tires on in the wheels section for some ideas.

Good luck,

GregS
'84 300D, 173k
'90 300CE, 163k

Get factory tires (Michelin MXV4 195/65R15) with straight wheels and you'll see a ride improvement. MB engineered the suspension with those tires & that aspect ratio in mind. Subframe bushings do go bad over time. They collapse internally making it hard for a mechanic to spot.
.

Just to add to the accurate comments so far, note that the stock wheels are very lightweight compared to the average 15X6.5 alloy, and of course the smaller tires will have much less weight as well. Compared to stock, your unsprung weight ratio is very high, causing poor inertial response of the suspension. In addition, there can be problems with the soft front bushings handling the stresses imposed by the wider, stiffer tire arrangement.

Steve

thanks all! really appreciate it.

So what i'm looking at is a change in tires. Ouch! big drain on the pocket as these are relatively new (1 year 10,000 km on it). Now i have to choose between aesthetics and feel, hmmmm.

A friend opined that the springs mights also be going bad. Is this a possibility?

I'd really like to make sure about these aspects because, while I really love my car, it's not really cheap to repair (spent about $4 K since i bought it, including dagger looks from the wife).

Will i get what i want in definite terms looking at: (1) change in tires; (2) new subframe mounts; (3) new springs, or are there still others needing replacement?

this is really a great site!

A couple of months back, I swapped my 15" 8 hole wheels (with 195/60/15 tires) with my friend's 15" 7 hole wheels (with 195/65/15 tires) and immediately got a more comfortable ride.

Haven't even worked on my front end stuff yet (damper, idler arm, shocks, etc)!!!

Needless to say, i was pleasantly surprised...:D

Azhari
Babybenz 1991 190e 1.8

I think it's always a problem to balance looks and comfort.

If you want a more comfortable ride, you probably have to give up those tires for a set of higher profile ones.

Good luck!

Azhari
Babybenz 1991 190e 1.8

If it were my car, I'd put factory sized tires and Michelin MXV4 on the car and see how I like it. This will have a lot more effect on your ride than replacing subframe mounts and springs that are in decent shape, possibly even if those parts are broken.,

OEMs do a lot of engineering work to "tune" the ride quality to the frequency transmission characteristics of the design tires. Suspension and subframe bushing design and durometer are specifically tuned to attentuate the primary frequencies transmitted by the tires. Tires are an integral part of the suspension and substituting short/stiff sidewall tires will normally dramatically increase ride harshness, so you have to be willing to accept this for the "look" and performance increase.

For some, it's not a good tradeoff.

Duke

Got it! "It's the tires, stupid". I will have to save up on that one. In the meantime i tried tweaking with some of screws inside the door panels and it was so gratifying to have lessened those annoying cabin noise being translated by the short/stiff sidewall tires i currently have. I'll be checking inside the dashboard next to see if there are others that i can still manipulate.

Thanks to all of you!

It's also the HD Bilsteins that are adding to the harsh ride. "Comforts' would have been a better choice, I think.

I don't think hds or comforts would make such a big difference. I rode in my friend's 300E and he uses HD's, however with bigger sidewall tires and it's so quiet that its' driving me nuts jsut trying to mimmick the the ride with my car.

124Addict

The other day I gave a ride to someone who had never been in a 300E before. They went on and on about how incredibly smooth and solid the car's ride was. He asked if I had a softened suspension or something. I said it was simply a stock 1991 300E with Bilstein HD shocks.

In my opinion if everything else is right, the car with HDs just glides, well controlled, but smoooooooth.

Keep us posted,

Haasman

one question though about changing to a higher side wall tires - if i decide to change it, am i not just hiding the fact that there might be some other loose parts or other components that need repair and contributes to the annoying sounds when i manage bumps and other road imperfections? Because really i don't mind hearing the solid "thud" sound as long as its not a "blag", "eek-eek-eek" or rattling sound.

Thanks again.

124Addict

I re-read your original post regarding the ride and noises but now I am not so certain as to exactly what is it that is really bothering you.

Would you mind being a bit more specific. Is it road noise? or the car's suspension reactions to road imperfections? or .... Give us some details or .... tell us as if we were to go duplicate in our cars and look for the same thing that is irritating you.

Help us help you.

Haasman

One more thing
 

Your car probably does not have it or else you would have mentioned it, but some W124 sedans and all W124 wagons got the hydraulic self levelling rear suspension. A common failure with this system is the accumulators (air cells or nitrogen cells). The symtoms are initially an underdamped, bouncy ride which deteriorates into a hard, bouncy ride. Having recently replaced ours, I can assure you the difference is dramatic. The ride and damping is now superb. It is amazing when you observe how many W116, W126, W123 wagons and W124 wagons are driving around with bad accumulators. When you follow them on a freeway you can actually see the rear bouncing on the slightest imperfection in the road.

Greg

You are so right and I just saw a wagon yesterday doing just exactly what you described. Actually it was one of my kids. "Hey Dad, look at the bouncing wagon."

Does 124Addict's model have the self-leveling rear suspension? I am not familiar with it.

Haasman

Thank you haasman for going out of your way to answer this post. You've been very helpful.

I went into the rehabiliation of my car's suspension in the hope that all the annoying sound i hear from inside the cabin will disappear. When I bought the car there were a lot of rattles, vibrations and cabin noise that i don't know from where the hell it was coming from. In my experience of riding my friend's 300E, i should not be hearing any noise at all except the, sound of the engine, stereo, the aircon, my voice as i sing along with my favorite tune and usual the "thud" sound whenever the car goes through bumps, this was even at a time that he has not changed the front shocks to HDs yet.

First, i started replacing engine mounts, transmission mounts and timing chain.
Second, replaced the front lower ball joints, tie rods, center links and idler arm.
Third, overhauled the brake calipers
Fourth, tightened and lubricated door panel screws and links
Fifth, was the recent repairs i stated at the beginning of the thread including bolt tightening underneath.

These all came from the knowledge i've so far gained from this site.

Don't get me wrong, but i've been satisfied with the suspension repairs so far and i admit that the car is a far cry from its original state from whence i bought it. There are bumps/road imperfections that make me smile because the car already manages it so well (very quiet , indeed, again except for the solid "thud"). However, there are bumps/imperfections, that does not feel well with the car where I still hear a lot of noise from underneath (front). Thus, the question "am I missing something".

Greg, to answer your question, yes, my car model had the rear self-levelling suspension. But I think the PO, instead managed to have it installed with an ordinary bilstein hd with no ill effects so far. My problem, however, is in the front and i dont have a bouncing issue, front and back. I'll be trying to, revert it to the rear self-levelling mode in the future if my budget will allow it since it will cost me about US$1,500.00 more.

As most cars age they tend to get "looser", which is caused by hardening of bushings, tire wear, and general wear and tear. This degradation in ride quality is so slow that it often goes unnoticed until a drive over a stretch of road you haven't traversed for a while sets off a light bulb. Sometimes it's primarily the tires.

A fresh set of tires with a full depth of new resilient rubber will provide attenuation to high frequency road inputs than the thin layer of hardened rubber on a worn tire won't, however, shorter/stiffer sidewall replacement tires will almost always generate more ride harshness than the higher OEM profile. OEMs tune the NVH characteristics to the OEM tires, and significant deviations from the OEM tires will often yield a significantly worse NVH profile.

Duke

124Addict

You posted earlier that you had a friend who has a 300E. See if you can set up an experiment and swap tires/wheels for a few hours. Drive your typical routes and see if that makes the difference. Could actually be interesting and fun.

Haasman

124addict,

From my limited experience, rattling from the front suspension was caused by the anti-roll bar rubbers.

I repalced all 4 for about 10 quid. At that price it was a cheap diagnostic tool. Cured it completely, and improved the turn-in no end.......well worth doing.

duke, thanks for the input. But would like to know also if a tire's speed rating provide any significant difference. Mine is currently z rated.

haasman, thinking of that also. I will update you of any development if i get to do it. but as an added note, his 300E is not stock. he's using slk wheel with 7 spokes and using tires sized 205/55/R16 front and 225/55/R16 rear .

paulg, if the anti-roll bar rubbers is the same as the sway bar bushings, then, i've already done that. thanks.

If any of the suspension/isolation rubber you have replaced so far has shown signs of hardening/wear, and particularly if you have been noticing continuing improvements, then go ahead and replace all of it. Mercedes uses a lot more rubber than most designs, and the cost of the isolation that provides is the limited lifetime of the material.

Steve

Yes! Higher speed rated tires have stiffer tread belts and sidewall stiffeners to give them the required stability for higher speed ratings.

I recall reading an article in the WSJ in the mid-nineties about the new S-class. A lot of owners were experiencing significant vibration problems. DB was at a loss to find a fix, and it was causing them a lot of embarrassment. One "fix" was to replace the OE V-rated tires with H-rated tires, but that did not solve all cases.

If anyone remembers this or experienced it, what was the final resolution?

I still have the original wheels and tires for my '88 190E 2.6, but circa 1990 I bought a set of takoff 300E 6.5" wheels and mounted a set of 205/60VR-15 Michelin XGTVs. These were replaced with a set of 205/55ZR-15 Dunlop D40M2s, which had to be replaced with a set of same size/speed rating Dunlop Sport 8000s due to a radial force variation problem.

These lower profile tires did increase ride harshness, but I found it an acceptable tradeoff for the improved steering response and grip. As you go to larger wheel diameters and shorter sidewalls, the harshness will increase and at some point it will become unacceptable, but the crossover point with vary with individuals.

Current models with large diameter short sidewall tires have suspension and subframe bushings specifically engineered for these tires, but ride quality can still suffer. I recently rode in a friends new M3, and it is one of most stiff legged and thumpiest car I have ever ridden in - comparable to older 911s. He also owns a 550 Maranello, which by comparison is smooth as silk, and so is a Z06 Corvette in comparsion to the M3.

Duke

sbourg, thanks, but would you, or anyone, know what other rubbers/bushings need replacement in a 124. I know i was not able to replace shock mounts, springs, subframe bushing (i don't know if it has one in front). Are there others?

Duke, thanks! I thought so also. I'm thinking of changing it later on to a v rating with higher side wall tires.