Looking at upgrading wheels and tires and came across a used set of wheels and tires 305/40/22 on 22x10 wheels. Not sure if they are too wide and would rub or cause other issues. Any thoughts out there? Currently running on 18s.

Dwight I really don't know the answer to your question but it does beg another question...why?
Are you going for looks, handling, ride? What's your goal?

I have to say the price for the wheels and tires are being offered for is quite attractive. Would love to see someone who possibly have 22" wheels on their vehicle.

Yes, 305/40-22 tire is too wide for GLC300 and at 31.6" is way, way too tall by massive 2.5" (more suitable for GL/GLS). It absolutely won't fit.

285/35-22 (ML/GLE size) is probably the largest (widest and tallest at almost 29.9") tire that can be fitted.

Thank you for that info as I had no clue on if that combination of wheel and tire would work.

You also have to consider the offset of the wheels, not just the height and width the tires.

Normally yes, but in this case its irrelevant. These tires can not be fitted on GLC300 even with a "hypothetical" wheel.

You posted a max size which if bought without checking offset might not work, so i think it is relevant to mention it

When quoting your reply, I was referring to Op's question of 305/40-22 tire because that's what I thought your reply was for, since you did not quote my "suggestion".

If your reply, however, was to my "suggested" max tire size of 285/35-22 (assuming it can clear), then of course it will require correct offset wheel. To take it even further, IMHO anything over 20" (even if 43/63 with 21") is detrimental to 300's performance.

My original post was to the op, that he needed to consider offset as well as size when upgrading, especially when buying used.

Then I stand by my original reply to your comment. While offset is always a consideration and is critical in some borderline fitments, the subject of the thread is 305/40-22 tire, which will never fit GLC, regardless of a wheel's its on. The end.

Thanks to all for the great information