saad911

Hey guys,
New to this forum. I have a 2013 c63 with the performance package.
So i was tired of the thinner 255 tires at the back, i switched them to dunlop sport maxx 275 30 19. I kept the original continentals in front which were 235 35 19. Now since i got the car when i make any sharp turns the car feels very floaty, as in the tires in front and rear take around a millisecond to correspond with each other. I got my alignment done twice and still no difference! This was done from the local Merc dealers here. I then read on a few forums that if i put wider tires at the back i should change the tires in front to wider ones. I had no option available than continentals again but this time they are 245 35 19. Still the same feeling. I changed various tire pressures, now the fronts are on 38 psi and rear are on 36 psi. What could be the problem? Should i spend money again and change the tires exactly to the way they were? Please help me, does different threats in front and back really matter? I did alot of research before doing so and now im regretting it alot!
My car has done 18,000 kms only!! What would experts here recommend.
Thanks alot!

slfmde

275 WAY to wide of a tire for the stock rear rims - that IS your problem. You are getting a ton of roll in the sidewalls of your tires when turning. I have 265 Pilot Super Sport and with stock Continental up front and it feels great. I would say your tire pressure is low regardless though. I run around 42/43 front and 44/45 rear.

Ezec63

EXACTLY !!!!!!!!!!!!!!!!!!!!!!!

Go with a 10" width if you want to keep that 275 and a hard sidewall

saad911

Thanks for the reply guys, so you think i should just change the front and rear tires to stock?

CoolBDPhenom03

Or get new wheels

saad911

I love the original matt black wheels, rather change the tires than wheels tbh.

Ezec63

You can get away with a 245/265 setup that will give you a good balance of straightline grip and lateral agility. Or go with the stock 235/255 theres a reason amg went with that setup they gave up ultimate grip for fast reflexes.

Also dont mix and match tires go with the same tires back and front

Ezec63

Its the summer time now so depending on what you want you can go with a more aggressive tire. You seem to be looking for more cornering grip? Check out the yokohama AD08 incredible handling with a very stiff sidewall that will give you the opposite of that "floaty feel" makes the car feel very precise. Or the nitto nt05 that more afforable and will give you better straightline grip for a fraction less of the handling grip it is still very precise and stiff. Both tires are 200 tread wear so be prepared to get rid of them after the summer

saad911

THanks Ezec63. Where i live, its summer 10 months and a little cold the last 2 months of the year, rearly much rain as it is the middle east. I went throught Nitto, Unfortunately they do not have 255 30 19 for the back tires or do they?

Ezec63

O sorry man I thought you had stock 18" rims ! look at the ad08 tires they have your size but are pricey ! Honestly the best overall street performance tire out there with decent treadwear (toyo r888 if treadwear doesnt matter) i loved them

Merc63

I run 275/30/19 on my factory 19s and dont have any problems.

MBAdon

PSS 275/35's on my factory 18's and I love them. Just ran autocross with them last weekend.

C63_SantaFe

^^^Agreed the pilot super sports are the way to go. I also have the 275's and couldn't be happier.

Vic55

Same thing happened to me when I swapped my tires on the rear of my E63. I actually had Nitto Invos in the front and the rear and the car was lowered. I wore out the rear Invos and replaced them with the same exact tire/size/etc. The problem is the contact patch of the 4 tires working together had changed since the tires in the rear were brand new and this cause the floaty drifty feel at higher speeds. This will slow wear off as you wear the tires in (might went away after about 200 or so miles of good hard driving).

FYI I got an alignment too- that cures future tire wear by adjust camber, caster, and toe but the patch between the front and rear were off still due to the differentiation in depths. Search the W211 E55 (I posted there due to more traffic) forum for my post a few years ago.

ShaneN.

interesting theory. so i guess this is something people would feel regularly, on this board, beat as though the rear tires wear significantly faster on the c63s.


I had this same feeling when i put new rear tires on my c6 and now that i think of it, i didn't change the front at the time. although i went from a run flat to a cheapo non runflat so i figured it was just those two things that made the difference.