Hello all. I have a 2015 GLK350 4Matic with the AMG package and the split 5 star OEM 20’s. It had new tires when I bought it a few months ago but they used the same OEM Pirelli Scorpion 235/45/20’s. It rides a bit rough sometimes and I notice a lot of tire noise when cruising around 45 or so.

I was thinking about getting new tires from Michelin to smooth things out but now actually thinking about downsizing to 19’s with 245/50/19’s instead. Anyone have any experience with ride differences in the 45 sidewall on 20’s vs. the 50 sidewalk on 19’s? Don’t want to lose the look of 20’s if it is not going to be a dramatic increase in ride quality.

Thanks in advance.

 

I went from 19" wheels on a VW Touareg to 20" wheels on an M-B GLE. The 20" GLE wheels are uncomfortable, with new tires at M-B inflation pressure. It is what it is.

Going to 19" wheels will be a comfort improvement for you, and I applaud this idea. I don't see myself making the change to 19 inches because I don't feel like buying new wheels.

There would be a noticeable improvement in ride quality going to 19 from 20. 20 inchers are almost universally noted for harshness from people seeking "normal" ride quality on a base model vehicle. For example all non-AMG models.

 

With the same rims I think ride quality would be worse with 19, less rubber to absorb bumps. And I guarantee pot holes will hit the rim. I have 19 Michelin, I wish I went to 21

 

Thanks Chassis. That’s exactly how I would describe it - just a bit more harsh than expected. I have had 20’s on trucks before with a nicer ride but also a lot more sidewall than 45. I thought maybe it might be the Pirellis but I guess not.

Thanks again.

 

It's the physics of the thing.

SLR (static loaded radius) of the tire can only be so large on a vehicle because of brake, suspension and wheel arch space constraints. The current styling ethos is to fill up that SLR with wheel, and wrap the wheel with a thin band of rubber in the form of a low aspect ratio tire. The claimed benefit is appearance, the actual detriment is ride quality.

For a given aspect ratio, differences between tire manufacturers will offer little improvement in ride quality, because the physics remain unchanged.

On an AMG model, Porsche, Ferrari or Lamborghini, low aspect ratio tires and large wheels are appropriate. For a base model Mercedes, I think it's the wrong choice.

 

That’s exactly how I tried to describe it to my wife to lessen the reaction when possible new wheels show up stacked in the corner of the garage. It’s as if they just slapped 20’s on this car framed “SUV” because it would look great. Maybe they work on a mid-sized ML/GLE or the GL/E but it just seems a bit too much for the GLK.

 

Agree. They don't work that well on a base model GLE either. It's an appearance thing, to the detriment of ride quality.