Tire sizing question
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Joined: Jul 2020
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From: Arizona
c450
Tire sizing question
I've been searching the forums and there isn't a definitive answer about whether you should go 285/30/19 or 285/35/19 as there are people running both sizes and was wanting feedback. I currently have 255/35/19 on the fronts as well. Any thoughts would be appreciated. Thanks! (BTW I have a sedan with the 19 inch wheels)
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From: San Francisco Bay Area
2019 C63CS
You use a tire comparison tool and see how they compare. The main difference will be the diameter and that will throw off your speedometer. Your 255/35 is already smaller in diameter compared to the 245/40 OE size. The other thing to keep in mind is wheel width. Don't put a wider tire on too narrow of a wheel. You also don't really wanna go that wide in the front. You'll likely just get a ton of tramlining, and you need to have sufficient fender clearance to not rub under any kind of suspension compression.
https://tiresize.com/comparison/
https://www.tiresandco.ca/tire-equivalence-advice.html
https://tiresize.com/comparison/
https://www.tiresandco.ca/tire-equivalence-advice.html
Last edited by superswiss; Nov 9, 2023 at 01:02 PM.
Thread Starter
Member
Joined: Jul 2020
Posts: 181
Likes: 21
From: Arizona
c450
You use a tire comparison tool and see how they compare. The main difference will be the diameter and that will throw off your speedometer. Your 255/35 is already smaller in diameter compared to the 245/40 OE size. The other thing to keep in mind is wheel width. Don't put a wider tire on too narrow of a wheel. You also don't really wanna go that wide in the front. You'll likely just get a ton of tramlining, and you need to have sufficient fender clearance to not rub under any kind of suspension compression.
https://tiresize.com/comparison/
https://www.tiresandco.ca/tire-equivalence-advice.html
https://tiresize.com/comparison/
https://www.tiresandco.ca/tire-equivalence-advice.html
Out Of Control!!
Joined: Nov 2018
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From: San Francisco Bay Area
2019 C63CS
I tried the tire comparison tool and the 285/30 was a -2.1 at 90mph while the 285/35 was a +2.1. I see a lot of people running both sizes so I was trying to see if there is a general recommended. I currently have a 295/30/19 on right now and lowered but found I slightly understeer in hard corners so was looking to go to a 285.
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Joined: Jul 2020
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From: Arizona
c450
The general recommendation is equal or smaller diameter than OE, so that your speedometer never shows less than actual speed. Also keep in mind that if the revs/mile front and rear are off by too much from each other then your ESP may get confused and not work correctly, and in the 2019+ FL models you may confuse AMG DYNAMICS which does torque vectoring and actively shapes the handling of the car. You didn't say what year your sedan is.
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2019 C63CS
I just mentioned it because you said you are understeering. That's something AMG DYNAMICS is supposed to eliminate. FWIW, the 63S coupe stock size is 255 in the front and 285 in the rear and it doesn't understeer. 295 isn't that much more, so your issue is likely the modified suspension and not the tires.
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Thread Starter
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Joined: Jul 2020
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From: Arizona
c450
I have maybe assumed it may be the springs, but visually compared to the 295, the 285 bulges much less and looks like it fits nicer. Also, if traction control is off, does Amg dynamics still affect the car? I would assume so but just wanted to check.
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2019 C63CS
Yes, AMG DYNAMICS is always active. It controls the electronic locking differential and still does torque vectoring. That isn't affected by whether traction control is on or off.
Out Of Control!!
Joined: Nov 2018
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From: San Francisco Bay Area
2019 C63CS
Just wanted to re-emphasize, at the end of the day you changed your suspension geometry by lowering it, so that is your much bigger issue. Most off the shelve suspension mods make cars worse, IMHO. I still remember one time I came up on a guy in an Infinity with lowered suspension on one of my canyon drives. He tried to keep pace, but his car was skipping all over. The suspension totally ruined it. He almost flew off the road trying to stay ahead of me while I was casually following him. Your tires likely don't have an optimal contact patch anymore or don't make proper contact when the road gets bumpy.
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From: DFW
W205 AMG
I tried the tire comparison tool and the 285/30 was a -2.1 at 90mph while the 285/35 was a +2.1. I see a lot of people running both sizes so I was trying to see if there is a general recommended. I currently have a 295/30/19 on right now and lowered but found I slightly understeer in hard corners so was looking to go to a 285.
Also keep in mind that if the revs/mile front and rear are off by too much from each other then your ESP may get confused and not work correctly, and in the 2019+ FL models you may confuse AMG DYNAMICS which does torque vectoring and actively shapes the handling of the car.
