I've mentioned before that the biggest thing I notice when going from my long-term GL350 to the AMG version is the ride quality. Sure, all that extra power is nice, but I really notice the comfort in the high-performance version. Everything on my GL's suspension is electronically controlled -- air springs, adjustable dampers, and even active anti-roll bars -- so I thought maybe it was just software tuning that made the biggest difference. After talking to Mercedes about it, it seems that the culprit might be the tires.
Before you get too far into this review, let me warn you that it's as much about the tires and how the GL responds to them as it is a car review. This is a long-term update, and you can find all sorts of driving impressions elsewhere on our site, and links to previous GL350 updates can be found below. So go ahead, leave your comment about this being Motor Trend, not Tire Review Weekly, and don't bother with the rest of it if that will make you feel better about yourself. For those of you interested in what it would be like to actually live with a GL and have to do a real world thing like buy new tires, please read on.
The long-term GL just turned 30,000 miles, and it seemed like a great milestone to change out the tires. The factory all-seasons still had 5/32 of an inch of tread, but with our yearlong loan quickly coming to an end, there was no time like the present. AMG GLs come equipped with Continental CrossContact UHP tires on their 21-inch wheels. and in theory that's an available tire on the GL350, but it is rare to find a summer tire on dealership lots. We ordered up a set in the factory size, 275/50ZR20, and had them mounted. You might be wondering how wise of a decision it was to switch to summer tires in January. It just happened to be one of the coldest days of the year as I drove to my local tire shop in Huntington Beach. It was a brisk 52 degrees made worse by a damp ocean breeze, and the coffee shop had already sold out of almond croissants. In other words, summer tires are all-season tires around here.
So let's talk results. The difference in ride quality with the Continentals was immediate. There is a rolling plushness that was never there with the Pirellis. Small harsh or sharp impacts now are absorbed by the tire sidewall, leaving the bigger stuff to be attenuated by the suspension. The Comfort Mode feels more luxurious, while Sport Mode hasn't lost any sharpness. There is now slightly more feel through the steering and definitely more through the seat of the pants. The old tires always felt like they were grinding over the pavement, but these tires seem melt onto it. It is hard to say what the tires feel like at the limits, as the GL's stability control intervenes at what feels like predetermined g-forces rather than tire slip. Again, the tires feel better when driven harder, but it is hard to say the SUV's performance has really improved.
Besides being more comfortable and more confidence-inspiring, they seem quieter. The GL has always been pretty quiet inside, but the road noise has fallen quite a bit. I haven't been able to put enough miles on the GL to see what these tires will do to fuel economy. I hope that before the next update we'll have enough info to make a conclusion on efficiency.
Obviously we have the luxury of running a summer tire year 'round, and not everyone does. This winter it looked as though any American that doesn't live in Southern California, Florida, or Hawaii, couldn't survive without all-seasons. For those who find themselves in the snow regularly, we'd suggest running these tires in the warm months and switching back to all-seasons or even snow tires as weather requires. We are constantly talking about the difference a tire can make on performance cars, but even on the daily commute I have a seen a huge difference on our giant family-hauler.
More on our long-term 2013 Mercedes-Benz GL350 Bluetec:
|Our Car |
|Service life || 15 mo/32,827 mi |
|Average fuel economy || 21.1 mpg |
|CO2 emissions || 1.05 lb/mi |
|EPA City/Hwy/Comb Fuel Econ || 19/26/22 mpg |
|Energy consumption || 160 kW-hr/100mi |
|Unresolved problems || None |
|Maintenance cost || $1466.97 (3-oil change, AdBlue top-off; 2-change brake fluid; 1-cabin-air filter) |
|Normal-wear cost || $837.11 (replace front/rear brake pads) |