gavinhuang

I recently purchased a 2018 c300 sedan with sport suspension. I didn't know this (I know it's stupid ) until I have been driving for some time and noticed big shocks when I drive over bumpy road. This is more obvious when Im driving on highway. My butt almost left the seat once because of the bad road condition. So, I don't know if the sport suspension could be adjusted and softened. I called the dealer and it's just phone transfer to another transfer and wait and wait....I know it would be very expensive to replace the entire sport suspension with a regular suspension. I'm not sure what to do. The tire pressure readings are 38 38 front and 41 41 rear. My car is RWD. The pressure suggestion on the gas cap is normal load 36 and max load 39 for the front and 36 45 for the rear. I think lower the tire pressure probably would not do any help. I definitely prefer the more comfortable and smooth drive. Just want to seeking some great suggestions or any comments from you guys. Thank you very much.

cylaptor

it is necessary to check which equipment package the car has in the base. Based on this, it can be determined what can be up and what not. The C-Class is very light and undemanding to replace and adjust the suspension.

gavinhuang

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gavinhuang

Yeah that's true. While I was having the test drive, the road condition near the dealer is very good and I never ran into any big bumps. I thought that's how it is.

Keith66

Lowering the tire pressure will help cushion the ride somewhat. What size wheels and tires do you have?

I have 19" wheels and I run my tires between 32 and 34 PSI cold all around. If I bump them up to ~40 PSI cold I can feel the difference, gets noticeably harder.

gavinhuang

Thanks for the reply. My front is 225 /45 R18 and the rear is 245 /40 R18. It is all-season tire.

Keith66

You're welcome. I would try dropping your pressures to 36 PSI all around and see if you notice a benefit. As always, over time your tires will tell you when you have the perfect pressures for your setup:

https://www.knowyourparts.com/techni...ing-tire-wear/

If your tires are run-flats, that's most likely a big factor. If they are run-flats, I would swap to non run-flats as soon as you can:

https://www.autoweek.com/car-life/a2...and-tradeoffs/

Beyond that, if you do your own work or have the means, I would check your struts for any signs of leakage (oil seepage) and depending on your mileage, maybe consider some good replacement struts.

gavinhuang

Appreciate it! Yes, I do have TIRE WITH RUN-FLAT PROPERTIES. I think the struts are fine as the car is right on 20k mile-age. I believe the dealer has checked all that before selling it to me lol.

Andy74

The previous owner removed the run flat into normal tires. I guess he wanted a smoother ride. So I had to buy a spare tire and look find a space in the boot to place it. 🤷🏻‍♂️

Keith66

Yeah dude, switching to conventional tires should make you much happier with the ride. Agreed, at 20K everything else should be fine.

If you are looking for tire opinions/recommendations, I would recommend Michelin Pilot Sport AS4 tires. Excellent tire.

Good luck!

Keith66

Great point! I need a good backup plan also. I have no spare and right now I'm relying on AAA Road Service if I ever have the need (knock wood!). I highly doubt AAA would have a 245/35/19 on their truck, lol

gavinhuang

Did you just put the spare tire in your trunk? I wonder how much it would take to replace all four run-flat tires to regular ones on a 2018 c300 at my local mercedes dealer.

Andy74

Yes where else am I going to put it 🤷🏻‍♂️
You dont have to replace them at the dealer any good tyre shop will do.
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Andy74

Hhhh now I am imagining AAA coming to your rescue in a Brabus 800 😂
I got a spare wheel called "space saver". I just placed it in my trunk.

gavinhuang

Thank you very much. Will definitely take a look. How about this one tho ? Thanks: https://www.bigotires.com/tires/sku/...254518_2454018

Keith66

You're very welcome!

Dude, if those are the kind of tires you're looking at, I'm not sure what to say. Stay safe and I wish you the best on your perilous journey of discovery?

gavinhuang

Lol...No, that was the first one I randomly found, but after some research, Michelin would be better. Thanks tho.

Keith66

Cool. I've heard good things about Continentals on MB's also. I've run Conti's before on a different car and they were good.