I just went through a super long thread about tire sizes that work on the coupes, but what about the sedan? I am currently shopping around for an intake (waiting on you BMS), dp, and a tune, and I know that especially after that it's going to be time for some new rubber. I have about 20k miles on these stock tires, so the time is right either way. Can I do 305's on the back? Which size should I go on the front to match ratio? I'm not very knowledgeable on tires so any input is appreciated!

 

on stock sedan wheels?

 

The Maximum you can safely go on the stock wheels is 285 in the rear. You would need aftermarket wheels to fit a 305, the stock sedan wheel, 19x9.5 rear, is not wide enough to hold bigger than 285 tire.
That being said, i run 255/35/19 front and 275/35/19 rear and it rides amazingly. Little to no loss of grip and very stable at highway speeds. If you go 285/35/19 in the rear, still stick with 255/35/19 in the front, a 265 could cause some clearance issues with the front suspension.

 

Yes I still have the stocks on

Thank you! I haven't really thought of upgrading the wheels, I really like the stock ones. I guess at some point I may upgrade if I need the bigger width, but for now it sounds like 285 should work. A couple people were saying that their tires wee still slipping in 2nd gear with a tune until they put 305's on, hence my concern.

 

I can understand that. After the tune and downpipes, my car is setup this way with our Stage 2 tune, the car wakens up tremendously. 1st gear is basically spin city if launching from 0 and 2nd is where grip starts to take over.
The Michelin PS4S do a really good job of fighting the traction loss even with a 285 tire, and if you eventually go 305 it will grip a bit harder as you have more surface area touching the ground.

 

What PSI do you fill the tires to with:
255/35/19
285/35/19

 

With wider wheels, what aftermarket wheel width and offsets for both front and rear are safe on the sedan such that it does not affect the handling or cause any rubbing?

 

Either your roads are as grippy as a drag strip, or you haven’t found how far your accelerator actually travels, lol! I have the same setup (275 rear size) on PS4s and I can break traction on just about any road at 40mph going straight just by punching it.

I wish this car could put down power, it makes me sad that a Camry (300hp now, hah) has a chance to get the jump on my car unless I caress the throttle!

OP - I have 275/35/19 on the rear on the upgraded forged AMG wheels. I think even 10mm more would make the sidewall bulge too much.

 

Can't answer your question directly but I've learned a few things when I changed to aftermarket wheels. If you're trying to fit wheels to a particular tire, you need to know what the wheel width range is for your chosen tires to be safe. That information will drive how wide of a wheel you can go with. A good resource to get that data is Tire Rack. If your tire is at the high end of the wheel width range, while the tire will "stretch" to fit, just know that your wheels will be more prone to wheel rash issues as they will stick-out further and not be as protected by the tire sidewall rubber. Regarding offsets, I wouldn't go any lower than your factory rims. The lower the offset, the more the wheel will stick-out and with a wider than stock wheel, your lower body panels will see more grit sling from the road which could lead to the need for mud flaps to protect your body panels. Just a few things to keep in mind as you do your research.

 

On your gas door there is a little chart that explains what PSI you should be at front and rear based on your cars normal carrying capacity and how fast you're normally going.
For example: I normally have 2-3 people in my car and i generally like to stay on the faster side so i keep mine around 42f/40r. It really depends on your driving style but use the chart for reference.


On the C63 sedan we generally run a 20x9 front and 20x10.5 setup. For the offset, it would depended on whether or not you are lowering the car and the width youre choosing to go with. Here is an example of our S10 wheel on a C63S sedan, I sent a message to engineering to get the offset of the wheel and will update shortly.






I can too, i just like to take care of my tires and roll into the throttle to the point just before breaking loose.

 

Good info. Few questions:
1. Does the grit sling issue apply only for the fronts or for both fronts and the rears?
2. I can measure this I guess, but still gathering info - Is there some room for going with a lower offset than factory or there is literally zero room?
3. Any idea how much spacing there is between the inside rim of the wheel (or the hub - whichever is easier) and the suspension components w.r.t. stock offset on C63S sedans (38 in front, and 56 in the back) ? When going for wider wheels, this could possibly help determine the maximum offset you can safely go with without causing any rubbing with the suspension components.

Thanks for the info.

For my W205 sedan, I believe the stock wheel setup is 8.5J x 19 H2 ET 38 in the fronts and 9.5J x 19 H2 ET 56 in the rears. I was considering switching to 255 in the fronts and the 285 in the rears with 19" aftermarket rims and stock suspension/height. If I go with 9" width in the front and 10.5" width in the rear, what would be your recommendation on the safest offsets without any rubbing on the inside (possibly even on full steering wheel turns)?

 

[QUOTE=Tuxdude;7825729]Good info. Few questions:
1. Does the grit sling issue apply only for the fronts or for both fronts and the rears?
2. I can measure this I guess, but still gathering info - Is there some room for going with a lower offset than factory or there is literally zero room?
3. Any idea how much spacing there is between the inside rim of the wheel (or the hub - whichever is easier) and the suspension components w.r.t. stock offset on C63S sedans (38 in front, and 56 in the back) ? When going for wider wheels, this could possibly help determine the maximum offset you can safely go with without causing any rubbing with the suspension components.

Again, I can't give you specific guidance on how a particular wheel and tire will work with your car. That determination is best left to wheel manufacturers that should have interference opinions. I have a C300 that had AMG 18" five spoke wheels on it. On this car, the front wheels were 7.5" wide and the rears 8.5" and I think the offsets were something like +45mm. I went with 8.5" wheels on all four with a +48 offset. I didn't go with larger tires so my originals worked with no interference issues but the fronts were stretched to the maximum allowable by the tire manufacturer. Some amount of grit sling was always an issue with AMG wheels. You can make it worse if your proposed wheels and tires will cause the tires to stick-out further than they are right now. I would be more concerned with fender rubbing than suspension part rubs if you are going with wider wheels with more negative offsets than you have right now. In my case, the rear tire position didn't notably change, but the fronts stick-out a little further than before (more grit sling) but not too bad as I can determine right now. Also, curb rash susceptibility is a little worse but again, not too bad...will have to be more aware of parking situations. One other point, I'm told that you have to make sure that your new tire selection does not create a greater than 3% front to back difference in mounted tire diameter. If they are, you need to research ABS issues as I've heard some say that that system could malfunction if the wheel RPM's are too different for a given speed. Again, I am no expert on these things but credible sources have given me guidance on wheel/tire selections. There appear to be a number of knowledgable people on this forum that can give you technical and practical experience advise. Good luck!

 

Thanks for the info. Don't want to derail the thread too much, I will start a separate thread for my specific questions.

 

These companies treat offsets as trade secrets - they will probably not give them out.

 

I think you'd want to do a 285/30/19 with a 255/35/19 to more closely match the overall size. If the 285 had a 35 aspect ratio it wouldn't match as well.


https://www.discounttire.com/learn/tire-size-calculator

 

I've been running 255/275 since I replaced my factory tires, in that 3+ years I've run them at 37/32 psi.

 

did you ever find the answer to this?
thanks