Whining noise 2017 C43 Sedan while coasting - thoughts?
The outside of the tires look like new.
When I got the car (a CPO) about 4000 miles ago, the tires all looked fine, and the alignment was checked.
When I get the new tires I'll have it aligned too, but standard alignment on these cars are pretty aggressive.
Hopefully, the non-runflats will help.
They will also let me substitute for a non-RFT. I can of course look up good all-season Conti options, but if anyone has experience with a good, performance-oriented Conti all-season option, please let me know.
Hopefully this takes care of the noise from the rear and the front end’s tendency to grab the road crown and pull right with the stiff sidewalls.
They will also let me substitute for a non-RFT. I can of course look up good all-season Conti options, but if anyone has experience with a good, performance-oriented Conti all-season option, please let me know.
Hopefully this takes care of the noise from the rear and the front end’s tendency to grab the road crown and pull right with the stiff sidewalls.
On a side note, it is about 95 F degrees here today (ambient temperature) and very humid (heat index well over 100). Had several errands to run. First time driving my car in about a week (been using my truck instead).
Heard the noise very faintly initially when cruising in the 45-50 mph range, but after a few minutes, it disappeared. Wasn't present in either C or S+.
In my case, I've noticed that the noise seems to be temperature-related. When it's warmer, it seems to diminish or disappear. I never remember hearing the noise prior to my first oil change back in May, so I can't say what effect extreme cold had, if any.
The outside of the tires look like new.
When I got the car (a CPO) about 4000 miles ago, the tires all looked fine, and the alignment was checked.
When I get the new tires I'll have it aligned too, but standard alignment on these cars are pretty aggressive.
Hopefully, the non-runflats will help.
I'm still waiting to have my tires looked at.
Took my car out for a drive again on one of the hottest days of the year so far (92 F with heat index values in the 100 degree+ range) and again, in the hot weather conditions, the noise was NOT present.
I can't believe how happy I am with the Michelins.
I changed the pressure to what Michelin recommends for the car and it has made all the difference. I'd bet that the fully laden pressure that MB recommends is one of the major factors to the tires wearing out so fast.
The car feels amazing and is so quiet.
I can't believe how happy I am with the Michelins.
I changed the pressure to what Michelin recommends for the car and it has made all the difference. I'd bet that the fully laden pressure that MB recommends is one of the major factors to the tires wearing out so fast.
The car feels amazing and is so quiet.
The Best of Mercedes & AMG
I can't believe how happy I am with the Michelins.
I changed the pressure to what Michelin recommends for the car and it has made all the difference. I'd bet that the fully laden pressure that MB recommends is one of the major factors to the tires wearing out so fast.
The car feels amazing and is so quiet.
Regardless, I'm glad switching to non-RFTs has helped your issue. With the amount of camber these cars have on the rear tires, it basically pitches the inside shoulders toward the road surface, which cannot be good for either noise levels or ride quality when you have super-stiff sidewalls.
Has there ever been ANY other AMG car that has come with runflat tires, prior to the C43?
On a side note, earlier in the thread, someone said a technician said that the noise was the result of the Performance Exhaust hardware and cold weather. I have the PE, and I don't seem to hear the noise in hot weather. In my case, I think it has to be 1 of these 2 issues.
The conditions I outlined in 1st post is the kicker here folks, very specific with no throttle while coasting during specific speeds. I suspect if the whine happens to you under those conditions as GWSHARK outlined, it's the differential, not the tires and certainly not wheel bearings. A noise with the tires would be very different sound under different conditions, same with the wheel bearings so if you have a whine pitch that is loudest just around 80-85km/h while coasting from 90km/h, then take it in. It's louder in the colder weather as the noise travels more but still happens in hot weather (30c+), but is not as pronounced and is not as noticeable from 90 km/h to 78 km/h.
Last edited by Seanhfx; Jul 9, 2019 at 11:14 PM.
I can't believe how happy I am with the Michelins.
I changed the pressure to what Michelin recommends for the car and it has made all the difference. I'd bet that the fully laden pressure that MB recommends is one of the major factors to the tires wearing out so fast.
The car feels amazing and is so quiet.
The noise seems to disappear completely in hot ambient conditions (85 F or above). Haven't heard it in a week.
Tonight, driving home in cool conditions (74 F), I heard the noise while traveling at 50 mph. My noise is most pronounced while I'm lightly applying the throttle to maintain speed. When I remove my foot from the throttle, the noise disappears or becomes so faint that it's hardly perceptible. In other words, the noise I experience happens when I'm *not* coasting.
It's like high-pitched whistling noise, as opposed to a mechanical whine (which is why I'm ruling out the diff. in my case). Can only hear it if I have the radio turned off.
Definitely coming from behind me. Could this be exhaust related? Something to do with the PE?
Last edited by Jujigatame; Jul 14, 2019 at 12:01 PM.
When the pressure is increased beyond the recommended pressure, the contact patch of the tire actually shrinks. The increased pressure usually causes the center of the tread to protrude further out than the rest of the tire tread. This is a problem because now the majority of the tire’s traction is coming from only the center of the tire, reducing the overall contact patch of the entire vehicle. With our cars being highly cambered and the runflats stiff sidewalls, it seems that it would cause the majority of the wear on the inside (which, coincidentally, is what most of us have experienced).
Yeah that doesn't sound right....says to use 39/39 PSI. That is WAY to high for the rears.
Today, I drove with the PE off in C. First off, I couldn't believe how quiet and docile the car was (which I was impressed by). Second, no noise on or off throttle at the speed I usually hear it.
Car is scheduled to go up on the lift on August 5th, just to completely evaluate/rule out the diff and go from there.
Good luck all.
Do you have any technical information where I can read up more on it, or a diagram?






