^no, it makes no difference how heavy your bike is. "It never gets easier, you just get faster."

The analogy to weight lifting does not work at all. When lifting weights, add more weight is how you increase resistance. On a bike, shifting gears is how you increase resistance. You can pedal a 100 lb bike at 5mph or you can pedal a 17lb bike at 20mph, you'll be doing the exact same amount of work. (disclaimer: numbers picked at random, I didn't do any actual math)

There's actually this 10+ page argument between sickvermin and umd on this exact topic in Fitness & Training. It ended badly