It's true that extra weight
mostly only come into play when you are accelerating or climbing.
Originally Posted by
pdlamb
Once you're rolling on a flat road, heavy bikes don't take any more energy to pedal than light bikes.
But if this were true you'd be able to maintain bike speed while pulling a freight train on the flats. So more weight does take more energy. Always. It's only a matter of how much depending on the situation.
OP: get a trailer and load it up with bricks... better work out!