Re: 20x10's on ecodiesel - 4 mpg decrease
Its not sticky that gets you...its rolling resistance. More tire on the ground creates more resistance (in addition to more grip in turns). Verify your tire pressure and bump them a few psi, and I bet you get some of the mpg back. I run 40 in my fortera 20s (stock summit wheels) and have good wear, nice ride, and decent mpg considering winter blend and short commutes through the mountains to work.
'14 WK2 Summit EcoDiesel
'01 Ram 2500 QCLB Cummins 6spd 4x4, '92 XJ 4.0/auto, 91 Daytona CS/AGS (original owner), 89 Shelby CSX-VNT #135, 87 Shelby CSX #133, 86 Shelby GLHS #499...and some Buell motorcycles for nice weather.