Originally Posted by
aaronmcd
I disagree. 25 in a group feels like 20 or less solo. 20 mph solo requires around 180 watts, or 2.65 w/kg. I can climb at 4.6 w/kg for 20 minutes, and am a good bit slower than most of the A ride. I think 2.65 w/kg would be at the back of the B ride. Basically, if you have to work hard to ride 25 mph in a group, you will get dropped way off the back on the hills.
W/kg is meaningless for flat riding. Your cross-section increases significantly more slowly than your mass (Square-Cube law). For flat riding, its all about raw Watts. Just look at the number of large riders you see flying on the flats who burn out on the first hill.