On an inbound commute to work recently, Truck Trend art director Voehringer noticed the GL's tire-pressure warning light had come on. "Once in the garage I put a gauge to each tire and saw the driver-side front was down 5 psi. I took it over to Just Tires, and they found a nail close to the sidewall."

Patched and ready for the road, the set of original-equipment Continental 4x4 Contact tires wouldn't be around for long-with just over 22,000 miles, the tread had become even with the wear bars, signaling a needed replacement. Mercedes uses four different OE tires for the GL, one being the new Michelin Latitude Tour HP, which we opted to try in favor of the 4x4 Contacts. Cost for the Latitudes, size 265/60R18, from Tire Rack was $772 ($192 per), with installation running $115.66. Total cost set us back $887.66.

Months/miles in service: 10/22,124
Avg econ/CO2: 15.7 mpg/1.33 lb/mi
Unresolved problems: None
Maintenance cost: $234.91 (oil change, tire rotation, inspect brakes)
Normal-wear cost: $887.66 (replace four tires)