Originally Posted by
wphamilton
equals about 3%. Don't make it more complicated than it needs to be - the simple ratio of the difference over total weight.
Same speed, about 3% less power. Same power, about 3% more speed. At 8-10 mph the aero drag doesn't count for much.
I think that oversimplifies it, because you do have the aero component that doesn't change. Thus the difference is less on shallower climbs, its also less with higher watts.
For example at 3% grade with a rider putting out 350 watts, 6 pounds is going to make a smaller percentage difference, than it will with a 10% grade, with 175 watts.
Example 1 its 2 seconds per mile; Example 2 it's 32 seconds per mile.
So rider strength, and steepness of the terrain definitely affects the answer.