Inclined Stationary Bike Why would it make you work harder if you incline a stationary exercise bike? What's the physics involved? Assuming all other factors remain constant and only the incline changes, why would you burn more calories?
 A: A stationary exercise bicycle presents a load to your legs which is entirely frictional and is generated either by a drag brake acting on the wheel, a fan that stirs up air, or an electromagnet that induces eddy currents in the wheel rim.
None of these friction sources has anything to do with gravity; they would all work just fine in deep space- and therefore the load on your legs is independent of the direction of the gravity vector.
This means that tilting the stationary exercise bike one way or another will have no effect at all on the difficulty of turning the pedals on it.
A: You would need to counter your gravitational potential energy when on an incline so you would need to work harder. While on a stationary bike there is no change in gravitational potential energy. Essentially on a inclined bike you have to work against gravity pulling you down.
A: When tilting the bike machine, you are adding an additional gradient  that you must now ride against. This increases the amount of power your body needs to output to maintain the same speed.
It might seem counterintuitive, but remember that the floor underneath the exercise bike keeps moving, while the incline remains, as if you were actually riding up a hill.
If you are riding on a flat surface, the total power output is $$P= F_R\cdot v$$ which is simply the power needed to overcome the resistance of the machine so that you are riding with a speed $v$.
If you were to tilt the machine, an additional factor comes into this equation, and that is the power required to overcome the gradient. Assuming you maintain the same velocity in each case, the power you require is now
$$P=(F+m g\sin\theta)\cdot v = F\cdot v + m g\sin\theta\cdot v$$
where $\theta$ is the angle of the incline from the horizontal. In other words, now you are riding against the resistance of the machine plus a gradient when the bike is inclined.
A: To the best of my knowledge, it would not. Perhaps pedalling would become more awkward due to the incline but in terms of the mechanics/physics of the bike it would be the same.
Most stationary trainers have a resistance setting to deal with the difficulty of the incline. But this is not really your question.
I can’t imagine any significant mechanism that would make an incline burn more energy. Is there some mechanism you are thinking of when asking this question?
