Even 10lbs makes a big difference. As long as you're not losing power to do it, the math is just too overwhelming.
8% grade 10 mile climb, rider producing 250 watts, 10lbs makes over 4 minutes difference.
Even on a 1 mile climb, its close to 30 seconds. And 30 seconds may not sound like a lot, but if it's the difference between staying in contact and getting dropped, it's the whole ball game.
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You could fall off a cliff and die.
You could get lost and die.
You could hit a tree and die.
OR YOU COULD STAY HOME AND FALL OFF THE COUCH AND DIE.