JBRhee

I recently started commuting with my car on the freeway and I've noticed that the SLK doesn't have the smoothest ride. Don't get me wrong, I love my car, and I would never trade it in for anything else, but sometimes it's just a little too bumpy. I don't notice any road noise when the top is down, probably because the noise doesn't resonate inside the cabin, but when the top is up, the noise and ride is a little too rough at times.

My tires were all around 25.5 psi, so I thought that was the reason, but even after inflating them to 36 psi in the front and 39 psi in the back, I still experience similar ride smoothness.

What're your thoughts?

dsb

I agree it's not the smoothest ride. However, increasing your tire pressure will make it a harsher not smoother ride.

Also, I many times try various lanes to find the smoothest one. I never paid attention to this in my commuting-Camry but now I have learned the smoothest lane on my most traveled highways.

Mr Wolf

The ride is bumpy, but your in a 2 seat roadster not the E class get used to it. Wolf

Falco

Not to mention an extemely short car contributing to the possible harsh ride on the freeway.

bloflin

You have an AMG with AMG sport suspension. It will ride rougher than even the SLK350 with standard suspension.

If road noise is a problem, hit the + button on the steering wheel 4 or 5 times.

As and aside, why were you riding with you tires so low?

If road noise is a problem, hit the + button on the steering wheel 4 or 5 times.

Going to 36/39 will make it even stiffer.

SLK55er after some pretty extensive analysis, recommends 34/32.

I'm running 34.5/33

fredfromny

You may want to consider 17 inch tires. Debatable performance hit may be worth the smoother ride.

JBRhee

Hey Blofin,

What're the advantages of having a higher psi in the front? I was doing some research and all i could find was this:

"An underinflated tire will ride smoothly but feel sluggish, have mushy turn-in and go around corners with high slip angles or just not much grip at all. An overinflated tire will feel harsh on impact and over smaller bumps, and while responding crisply, will lack grip when pushed hard."

How's the ride when the tire pressure is 34/32?

bloflin

Rides fine.

Over on the other forum (benzworld) there is a fellow who has done some pretty extensive analysis and measurements.

Boils down to, the V8 weight on the front end is higher than load on the back. This is the reason for front higher than back.

Second, is his belief it must be the MB lawyers that make them quote a higher pressure, to ensure understeer. Perhaps also fall out from the Firestone debacle years ago (if you have to err to one side, err to high pressure)

Additionally, he's convinced running at 36/39 you will see all your wear in the center of the tire.

Then the final straw, was that MB doesn't seem to know what to set it at. The door sticker and the gas door sticker disagree. When asking MB service they were confused and no help.

So I went with the one person who seemed to know what he was talking about.

So to your quote above, 34/32 cold would not be considered an "underinflated" tire, but a correctly inflated tire.

His handle is slk55er.

slk55er

'Tis I with the handle "slk55er".

I do believe that for normal driving, 34/32 psi F/R is a good setup. The higher front pressure will provide a crisper turn-in and the lower rear pressure will reduce wear on the center of the rear tires. And these pressures are low enough to maintain a reasonable comfort level.

On the track, I use a 40/36 F/R setup which really seems to be excellent.

You can read more about my tire pressure recommendations at

http://www.benzworld.org/forums/foru...220298&posts=2

and about some of my on-track sessions at

http://www.benzworld.org/forums/foru...osts=10&fid=27

http://www.benzworld.org/forums/foru...id=27#M1485561

Gordon Haines

bloflin

Thanks Gordon, too many forums, and I forgot you were on here also.

Leef

I replaced my tires/wheels with 17" shortly after I got my 55. I opted for Michelin Pilot-2 tires, in part due to their quietness and ride quality, and AMG split-5 spoke wheels (got both from Tire Rack). The AMG wheels that fit the SLK32 fit the 55 also.

The ride is a bit less harsh. Can't say how much. Also, the wheels are protected better from potholes and curbs.

I've been running 32 psi. F/R. My dealer seems to like 30 psi all around.

Great car!