2015_C300_ATL

While I love a firm ride and the handling and control that usually comes with it, my C300 seems to have an overly harsh rear suspension. The ride can be pretty punishing coming from the read at higher speeds on anything but the smoothest of highways. I have the standard "comfort" suspension with 18 inch wheels and Continental Run Flats. I have lowered the air pressure in the tires to 30 lbs, and while it makes the overall ride smoother, the harshness in the rear still exists. Anyone else feeling the same way or attempted to do anything about it? I have thought about trying a softer shock first, but there doesn't seem to be anything on the market yet for the 2015 model.

MASSC450

I have a 2015 C300, but with the stock 19" wheels/RFTs and sport suspension, and I felt that the rear end bounced around a bit over bumps. I later checked the tire pressure and found that all four tires were low (35 psig). After inflating to the recommended pressure from the door sill sticker, 39 psig front...45 psig rear, I found the car rode BETTER...less bouncey over the bumps.

hpilot

I have the same setup you have. I keep 35 psi in all tires. Although it seems most people on this forum don't agree with me, I find the ride quality over bad roads horrendous. I haven't noticed that it was just in the back. It's hard to believe a higher tire pressure would help...

StanNH

I've been running 34/36. The pressures listed on the door are for maximum load and best fuel economy, but that certainly doesn't help with ride comfort.

Given the nature of the RFT's, even lower pressures won't really "soften" the ride, but they do reduce some of the slap and harshness over pavement breaks and rough surfaces. Even running non-RFT snow tires during the winter, I didn't find the ride ever got really compliant. I've also driven the C300 Luxury setup with the 17" tires, and felt even that was a fairly hard ride.

Basically, none of the steel suspensions with the original RFT's are really going to offer anything even approaching a soft ride over harsh road surfaces.

ManiacGT

Have you checked that the shipping blocks have been removed all round?