See also:

Cleaning the steering wheel and gear or selector lever
  Thoroughly wipe with a damp cloth or use leather care agents that have been recommended and approved by Mercedes- Benz. ...

Treadwear indicators
Narrow bars (tread wear bars) that are distributed over the tire tread. If the tire tread is level with the bars, the wear limit of 1/16 in (1.6 mm) has been reached. ...

Ride & Handling
When I first saw the wheels on my test GLK350 — those 20-inch rims and low-profile all-season tires — I was a little worried about how it would ride on Chicago's crater-filled roads. To my surpris ...