HELP with 275 & 305 Decision

[rnlaw11]

I have been reading this forum for the last week. I realize this has been asked repeatedly, but there doesn't seem to be a consensus.

My wife has a 2020 M4, and we decided to change the wheels to give it a beefier/sportier look. Ok, I mean I decided and she let me do it.

Her car has the 265/30/20 and 285/30/20 setup currently. I have bought:

* 20x10 et25 for the front and
* 20x11 et40 for the rear.

She is running stock suspension. I don't see her letting me change that anytime soon.

I would LIKE to run this setup:

* 275/30/20
* 305/30/20

But I see some people saying it will rub and others saying they run it just fine. I realize that the offset could be the difference. I have that setup on my car currently (CTSV) and I love the look. But can I get some advice PLEASE!??

I really did try to go through the forum thoroughly (you all have some GREAT cars) but I couldn't get anything definitive.

[MineralWhiteF80]

the situation that prevents a consensus is that every car is slightly different, everyone may have different suspension (ride height and alignment specs), different brands of the tires in one general size may actually be different sizes, and some people have different definitions of "rubbing" lol. So, it's hard to guarantee anything.

Here is what I can offer:

Your proposed front wheel/tire setup will fit, but may need a little massaging of the plastic fender liner. The 275/30/20 and 10" +25 wheel is the equivalent of running a 17mm spacer on your current stock setup. The main issue you might run into is that your proposed 275/30/20 tire is 26.5 inches and the front wheel well of the M4 really only likes a maximum tire diameter right around 26.3 inches (aka a 265/30/20). Anything larger and the tire will have a tendency in some scenarios to slightly rub the plastic liner, usually when making a turn or under compression while making a turn. You can typically hear the rubbing at very slow parking lot speeds when making turns. Most people will take heat gun to fender liner in the places that it is rubbing to soften the plastic enough to be able to push it back and create more clearance.

Your proposed rear setup should fit fine. Fitment wise, it will be the equivalent of running a 13 mm spacer on your 285/30/20 and stock wheel setup.

Your proposed setup wont look more meaty from a wheel-to-tire perspective, but it will look a little wider from the front or back view due to increased tread width. A 265 mm tire on a 9" wide wheel looks meatier than a 275 mm on a 10" wheel since you are increasing wheel width twice as much you are the tires width. The rear wheel should look the same "meatiness" as your current setup, but just with a wider tread width.

[idriveabmw]

Im on a 20x9.5 +18 and 20x11 +38 with 275/30 and 295/30 on the KW HAS kit. My fronts rub a bit under certain full turns a bit, rears are great. I would run a 265/30/20 up front, have also heard about people running 245/35/20 and 255/35/20 up front for more sidewall. I am curious about 305/30 for the rears, it seems some people have rubbing issues with it while others don’t.