I know it is an old thread but I think this is the place for my post.
Nowadays I realized an interesting thing and I am curious is anybody experienced same?
My car is a non facelift R171 200K with automatic gear (5G) with me the car's weight is ~1,5 tons and I use it rarely, about 8k km's in a year - mainly in the capitol with heavy traffic, some weekends with country roads, 1-3 bigger journey on highways.
I mainly used my car's gear in comfort mode and rarely I push the pedal to the metal but I am a typical calm person usually. As I can see doesn't matter my top is up or down the consumption doesn't change.
My fuel ('95 normal) consumption average is: 9,6 L / 100km on the last 15k km's since I own this car.
Urban: 9-10 L/100km
Country: 7-8 L/100km
Highway: 8-9 L/100km.
These datas belongs to my winter tyre size: 205/55 R16 Pirelli SottoZero SII 91H. My best consumption was 6,8 L/100km during a long country trip with 2 person and baggages.
When I bought my double sized AMG alloys for summertime (with Kumho Ecsta KU39 LeSport 94Y, front: 225/45 R17, rear: 245/40 R17), my consumptions are:
Urban: 10-12 L/100km
Country: 8-9 L/100km
Highway: 8-9 L/100km, so wider tyres obviously generates higher consumption.
In the last month I started to use my car's gear only in sport mode with my same habbits and wider summer tires and I realized that my fuel consumption is getting decrease... in general 1 L/100km less than earlier.
Anybody else got same experience guys?