I am thinking about buying a used 2024 GLC 300 SUV. Any problems from current owners, I should be concerned about. Also, it comes with 18 inch tires. I want to change my tires to 19 inch, I was thinking about 20 inches but the ride might be rougher. I want the height of car to be higher than with 18 inch tires. Do you find it hard to work the touch screen controls?

 

Changing the wheel size (diameter) will not change the ride height.
I have 18” wheels (winter) and 19” wheels (summer) and do not notice a significant difference in ride quality.
Doug DeMuro, well known car reviewer, has called the Mercedes touch screen controls the best out there.

 

The ride height is controlled by the diameter of the tire, not the rim. My 2024 came with 235 55r 19 Michelins. Dia is 29.18. They were a $600 option. I bought the car off the lot so that's what I got. According to Google, the tire on the 18" rim is 235 60r 18 with a diameter of 29.1. An infinitesimal difference. But you'll likely get a slightly softer ride. The tire on the 20" rim is a 255 45r 20. Guess what? The dia is 28.5". It seems to be about the look. Regarding the touch screen, it is a little cumbersome. But I have the Mercedes voice control trained to open and close the garage door, change the radio station (both for Sirius and FM), and she will set up "route guidance) when I tell her where I want to go. It has car wash mode which is nice, but cumbersome. I got **** on here when I compared the GLC's to the ease of use on my wife's 2023 GLE. The volume touch control on the steering wheel is useless. I think has to do with the angle of my finger. Reaching across to use the control below the big screen works fine. I think there is a sensitivity setting which I might try. The swing kick to open and close the rear hatch only works when my right toe makes contact with the underside of the car. Then it works about 95% of the time on the first try. Waving my foot under the bumper hardly ever worked. Another issue the rear camera popping open at low speeds. You can hear it but what it sees does not trigger the screen to show it. It seems to have something to do with looking for parking spaces. A lot of GLE owners have the same complaint.

I like the ride quality and quiet cabin. No rattles or squeaks. Driving on concrete is noisy but that's the same for everybody. The Burmeister sound system is nice, but I'd be hard-pressed to tell the difference between it and the standard system. Road noise is the killer. I like the toy spare vs run flats. If you are buying from a dealer, insist they show you the option list for the car. Again, if a dealer, tell them you want to see the Vehicle Master Inquiry (VMI). It's an internal document that shows all the work done to the car by MB, especially oil changes, cabin filter changes and other work. I'd walk away if they won't at least show it to you. I did that once because I smelled a rat. The Carfax may show the work. I've seen MB dealers put a Carfax in the listing that only shows what they did to the car. Nothing prior. Here's one like that from a reputable dealer. https://www.carfax.com/vehiclehistor...y5pXA3RYNXTJxc

We've owned/own 5 MB"s. 4 CPO's. 2014 ML350, 2014 GL450, 2017 GLS550,, 2023 GLE350, and the new 2024 GLC300. Very happy withe the GLC. I don't really care about gas mileage. I get 23 when all around town and up to 30 all highway.
Good luck and keep us posted. PS I suggest you double check all my tire info. It's actually the radius that controls the ride absent any suspension mods.

 

Touch screen controls are fine since. If you're worried, the bottom strip of the display will always let you change A/C no matter what menu you're in.

As others have mentioned, the rim size won't change the ride height much. You're better off investing in a lift kit if you really care. I'd recommend to fork over a little more and get a GLC350e if you can install a home charger or have one. It also has rear air suspension which can lift the car about an inch. The GLC300 isn't that special if you're in the market for other cars, unless you want the Mercedes touch. The plug in hybrid is a whole different story and delivers one of the best, if not the best, electric only range on a plug-in.

Regardless of which model you get, I'd recommend a warranty, either CPO or extended. Repairs can quickly add up to more than a year's worth of payments... something to keep in mind if you'd prefer to keep the car long term. Reliability is a toss up since the earliest iteration of the current gen X254 was released 3 years ago.