Quote Originally Posted by Eden View Post
If you have a reason to go less distance, but want a harder workout use the heavier bike. For example I can get a good workout on my commute, which is a set distance by using a heavier bike. If I were to use a lighter bike then I'd have to find extra distance to make up the time (my workouts are all set by time) - With the heavier bike I can still do the workout, but since its slower it takes the requisite amount of time.
See, that's what I'm doing. I'm using the heavy commuter bike to squeeze in a good workout in less time. I use the lighter bike for longer, faster rides.

And I did notice that when I rode the mtb often, I didn't see that much of a change in strength or endurance on the road bike. The speed was the only thing that changed.

This is an interesting discussion and thank you for sharing your thoughts.