Hi All,
Recently bought a 2019 glc63 but looking at different tire/rim options.
Two questions:
1. Why does the front tire setup on a 63 run 265 with a 9.5” wide rim while the same width rim is on the glc43 yet it runs a 285 tire?
2. Is it possible to run a rear glc 43 tire on the front of a glc 63 ?
3. Can a square setup be run on a glc63? If I wanted to run the front width all around what spacers would I need for the rear ?

Great question. I can try to answer.

1) 63 has a bigger engine which equates to more weight and more power. Bigger contact patch helps with traction and handling. For a perform a vehicles staggered tires help with stability and handling.

2) I don't see why not. But the radius of the wheels will be slightly off of you're running GLC63 fitment at the rear and GLC43 fitment at the front. This may negatively impact the 4matic traction control as well as reduce the handling and stability characteristics that make the GLC so great.

3) I don't see why you couldn't. You would need a 15mm spacer if you were to run the GLC63 front wheels at the rear. I'd advise against running a square setup though. Your traction control shouldn't be affected but your stability and handling will. Rear when drive his vehicle, the staggered setup helps handling and stability.

Hope that helps!

1/ I think front on GLC 43 are 8.5
2/ No , your wheel will sick out
3/ NOOOO way

Yes front is 8.5 but rear of the 43 is 9.5 and runs 285 width while front of 63 is 9.5 and runs 265. I believe that's the source of OPs questions.

Ok ,I see what he is trying to do !

1. On any given rim width, a limited range of tires will fit but you will see a slightly different tire profile. A wider tire on a particular wheel will "bulge" while a skinnier tire is described as "stretched". In other words, the former will have the tread stick out to the edge or even past the edge of the rim while the latter will have the tread stop inside the width of the rim.

2. Sure but you will want to ensure the overall diameter or circumference of the tire is very close to the same front to back as per other comments about impact to 4matic system and transfer case.

3. Square set up can work but as others have stated, many believe that the staggered setup is done for performance reasons. When it comes to an all wheel drive car though, under-steer is a common issue unless the vehicle has a rear wheel drive bias like the GLC43/63. Note that these each have a slightly different 4matic system. I believe the 63 is able to shift more power front and rear than the 43, 43 is more fixed but I've had a tough time finding reliable information on comparisons between current versions of the 4matic and 4matic+ systems.

Spacers do not address any of the issues you are talking about here unless you are thinking of putting 43 wheels on a 63 vehicle which has wider fender flares on the front. Spacers only move the wheel outward to make is stick out and appear wider, in comparison to the fender.

Not sure if you guys are running stock size tire/wheel setups, but Im looking to increase the size for the front tires to 275 and the rear to at least 315 or 325 wide. I would have custom wheels made so far the fronts would be 20x10 ET30 and the rear 20x11.5 ET28. Just wondering if you guys had any experience with fitment regarding this.

I run a square setup in the winter on my GLC 63 with Mandrus Arrow wheels and Michelin all season tires 265/45ZR20 with 25mm offset and 7mm spacers in the back. There are pictures in this forum under another tire/wheel thread.