OK, so I have done a little extrapolation based on pictures (see thread
http://www.m3post.com/forums/showthread.php?t=848092) and some math to figure the difference between the 265 and 275.
Here are the results for thread block width in mm
265/35R19 (Total thread width 254mm)
47+32+32+32+47 = 191 (75%)
275/35R19 (Total thread width 259mm)
58+38+38+38+58 = 230 (89%)
So even if the 275 total contact patch width is only 5mm wider than the 265 contact patch, it offers 39mm more rubber contacting the road because of the narrower grooves. This is 20% more
. This could justify the 2.9lb of extra weight (+12%).
Decisions, decisions...