For those who have replaced their RFT with non-RFT, I have a question.
My 2018 C 300 with AMG Aline pkge which includes their “sport” suspension has 225/40 R 19 front and 255/35 R 19 rear tires.
can I replace them with a “taller” tire or do I have to stick with the 40’s and 35’s?
TIA
Dave in Florida

 

As a minimum, taller tires will make your speedometer and odometer in error.

 

Understood.
The circumference of the tire is what matters.
IIRC Tire Rack has those specs on their website.
I am also concerned with rubbing issues.
But the end game is a quiet tire.
I do not plan on tracking the car so a low wear rating is not that important.

 

OK as the OP I committed to reporting back after I made the switch to non runlets. Here is my update...

I just drove home (local roads not very smooth) and motorway (15 kms) after having a set of 4 Michelin Pilot Sport 4S tyres fitted.

Many of you in these forums convinced me to do so against bulltish (that's the Australian way of saying it) from Mercedes Technical, one dealership and a number of tyre shops advising "not to do so" citing "your car is designed for run flats" to "you will get dash errors (this one form Mercedes Australia" to "your warranty will be invalidated (I am a month out of warranty anyway)..

Many of you also used the phrase "night and day" difference after ditching the OEM run-flats.

Well, you were all right ! It is night and day better.
I had a grin from ear to ear driving back home.
Smooth ride like I should have had when I bought this car new in 2019. Couldn't tell the difference in road noice but (emotionally) think these tyres are quieter (The tyre fit tech told me they would be).
Braking is better (but that may be just because of new tyres anyway.
I had a recommended full wheel alignment done (Disclosure - the car drives better partially attributed to this I am sure). They showed me my alignment readings which were out of whack in front (the car was never aligned for 2,5 years and after a number of recent pot holes it was certainly out of alignment too (evidenced by the outside wear of both front tyres (also pointed out to me).

Tomorrow after my grin form today wears off, I will be pissed at the %$#@&* Mercedes accountant who led the decision to save costs (I have it on good authority from an insider at Mercedes that the run flats choice and hence no spare was a cost cutting primary reason !!) thereby robbing me of silky smooth ride comfort from a $ AUD 300k + new car.
Then I will take the car out for a drive and put the grin back on...

I have also signed up for a Platinum package of "Total Care" road side assistance which includes towing, hotel expenses and other useable benefits. Just in case I bought myself (overkill I am sure) the VIAIR 400P Automatic tyre compressor / inflator / deflator ....

Thanks to this forum and all of you who contributed to my "happiness"...

For reference - I have the triple spoke 20" rims. Front 245/40 R20 99Y, REAR: 275/35 R20 102Y.

 

PS: I noticed my TPMS readings seem to be on the high side 280 KPa or 40 PSI ...all. round

The Fuel Cap card shows for 20" rims (2 passengers plus some luggage) 36 PSI Front, 38 PSI rear. $ Passengers / Full load - 38 PSI Front and 41 PSI rear.

I may lower the pressures to about 36 all round and see how this feels... More reporting coming up...