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I have a 2019 C63s Coupe. I'm currently running 285/30 sized tires on rear and I believe 255/35 OR 265/35 on front, not sure what size it came with for the front, whatever the default for the front is.
As stated by the title, I wanted to get Michelin Pilot 4s tires, and was wondering if it would be better to get 285/35 sized tires as opposed to the default 285/30 for the rear. It would be a higher aspect ratio and cover more sidewall, and maybe give better traction? Would this work? Would there be any disadvantages?
If it's not a good idea, what would be the best larger tire size to go?
Last edited by StormHawk; Apr 18, 2022 at 10:59 PM.
I think it might be too tall...although I cant say for sure. I don't recall seeing anyone on here running that size.
Most go with 295/30 or 305/30 depending on lowering status, wheel offset, etc.
Stock wheels stock height, no spacers should be good with either 295/30 or 305/30 (some go even wider). Not sure about 285/35.
I'm lowered on H&R sport springs with 15/12 spacers and I think I have room for 295, but 305 might be tight. I'm fairly certain I do not have room to run a taller tire like 285/35 (26.7 inches vs 27.9 inches tall).
The only reason you'd really do this is to have more protection between the wheel and the road against potholes and a bit of added comfort. At the same time you'd increase the ride height at the rear compared to the front and potentially degrading aerodynamics. Below is the comparison between the two. Theoretically it does improve traction by reducing your acceleration. The force acting at the contact patch reduces as the radius of the wheel increases, so with less force it's less likely to break traction, but at the same time it reduces initial acceleration as that force is what propels you forward. You'll essentially reduce the force and acceleration by about 2.25%.
Torque at axle = wheel radius * force at contact patch
Force at contact patch = mass of the vehicle * acceleration
So if you solve the above for acceleration or force, you'll see both decrease if the wheel radius increases since the torque at the axle and the mass of the vehicle don't change. Now this doesn't factor in drag, so it's only good for taking off from a dig. As speed increases, air resistance takes over and horsepower determines how fast the car accelerates as you need the power to overcome the air resistance.
The only reason you'd really do this is to have more protection between the wheel and the road against potholes and a bit of added comfort. At the same time you'd increase the ride height at the rear compared to the front and potentially degrading aerodynamics. Below is the comparison between the two. Theoretically it does improve traction by reducing your acceleration. The force acting at the contact patch reduces as the radius of the wheel increases, so with less force it's less likely to break traction, but at the same time it reduces initial acceleration as that force is what propels you forward. You'll essentially reduce the force and acceleration by about 2.25%.
Torque at axle = wheel radius * force at contact patch
Force at contact patch = mass of the vehicle * acceleration
So if you solve the above for acceleration or force, you'll see both decrease if the wheel radius increases since the torque at the axle and the mass of the vehicle don't change. Now this doesn't factor in drag, so it's only good for taking off from a dig. As speed increases, air resistance takes over and horsepower determines how fast the car accelerates as you need the power to overcome the air resistance.
Wow, amazing explanation, thank you. That made me understand it a lot better. In that case, would there be a significant increase in speed/traction to warrant getting 295/30 over 285/30?
Wow, amazing explanation, thank you. That made me understand it a lot better. In that case, would there be a significant increase in speed/traction to warrant getting 295/30 over 285/30?
I'm personally wary about going wider than stock, at least on stock power. Wider means a heavier tire, and that's all unsprung weight, and I'm not convinced that 10 mm gives all that much more traction. You didn't say you were tuned. I'm assuming you are currently on the PSS. The PS4S will give you more traction just by itself. I went from the stock PSS to stock size PS4S and the difference was very noticeable. The main thing that I keep telling people about traction is heat in the tire. If your tires are cold you will have traction problems. Below is a slide from Michelin showing grip relative to temperature. You can improve grip by simply making sure you get the tires properly warmed up. During the summer months on a hot day the traction is very different compared to a cool fall day or even a dry winter day. You can't make that up with going wider. The compound gets harder the colder the tires are.
Last edited by superswiss; Apr 20, 2022 at 12:41 AM.
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W205 C63s Tire Size: 285/30/r20 VS 285/35/r20
