Wheel offsets
 

I have been going around and around on what wheels I might possibly put on my 2019 SL450. I want to stay with 18" or 19" wheels. There appear to be a lot of MB/AMG OEM wheels out there that will "fit," with same dimensions and bolt patterns, but then comes the thought of the wheel OFFSETS. So, my question is: Just how important and critical is this measurement. If there is a difference of 10mm, which is less than 1/2", is it that critical? I always see posts from R231 owners who are putting spacers in to push their wheels out towards the edge of the wheel wells, so how much is too much? Obviously, we don't want the tires hitting the fenders, but within reason, how much can one usually "fudge?"

Even though we had forged 19"/20" AMG wheels on our SL550 which are wider rims than stock (9"F/10"R) we still used spacers to make the stance fit more appropriately with the width of the car (wider than a R230). But there is a balance here, one cannot increase the width of the stance without lowering the car. Otherwise all you see is tire profile when talking past the car.
We used 20mm spacers in the rear and 15mm in the front.

We used the same spacers also on our stock 19" AMG wheels and it looked great as well. The car was lowered electronically by roughly 1". ABC cars will be a bit lower than SL's on springs.
I assume you will keep the car at stock height you can increase the offset by roughly 10mm without looking out of place.

Stock AMG wheels are ET 35.5 front and ET 47.5 rear
Forged 19/20 AMG Wheels ET 27 front and ET 48 rear

The lower the offset, the more the wheel sticks out. So the Forged front wheel sticks out 8.5mm more.
For example, by adding a 20mm spacer in the rear I turned the offset from 48mm to 28mm

When selecting 3rd party wheels or wheels from other MB models, this is often where things go wrong. They just look wrong as they are inset too much, stick out too much and don't clear the brake calipers.

Hope this helps. If you have wheels in mind, I can assist on fit questions...

Well, Wolf, the wheels I would like, are the 19” AMG wheels you had on the front of your SL, only I would like to run the 19’s at all four corners.

The normal set would include two of each of the following:

Front Wheels: 9Jx19 ET27 (p/n A23140102007X15)
Rear Wheels: 10Jx20 ET48 (p/n A23140123027X15)

The 21mm difference in offset, even when considering that the wheels in the rear will be 1” narrower than the AMG regular 19”/20” setup still won’t work?


https://cimg9.ibsrv.net/gimg/www.mbw...cd75545af.jpeg

It could work but there is no accounting of how it will look. At minimum you will have to have a 12-15mm spacer up front to make it look half-ways equal.
I already returned the SL otherwise I would have tried it out as I still have those wheels laying around...