Why does a small change in incline angle make so much difference?
Here is the answer... Please note this will get a little bit mathematical. However I have kept it simple as possible.
In summary, this is because a greater component of your weight is working against you by dragging you downwards. This component of your weight increases out of proportion with the angle of climb.
For those who don’t need math or physics based explanation can stop reading now. Of course I would welcome corrections to this – I worked this out using the physics learnt at school.
Basically the force of gravity that works in the downward direction of the slope is:
Force = Mass * Gravity * Sine (Angle)
So if you are a 70kg person, climbing at 5deg:
Force = 70 * 9.8 * Sine (5deg) = 59.79 Newton (a unit of force)
The same person climbing at 7deg
Force = 70 * 9.8 * Sine (7deg) = 83.60 Newton
So this small change in angle has added almost 24Newtons of downward force that you have to work against.
It is interesting to look at it this way – How much weight should
I loose in order to make the 7deg incline feel like 5deg .. by shedding weight I effectively reduce the downward force working against me.
Basically I now want the following equation to hold true.
Force = MyNewWeight * 9.8 * Sine (7deg) = 59.79
MyNewWeight must reduce so that the force I experience is the same as I would experience at normal weight.
The answer: ... 50kg!! ... I would have to loose 20Kg! just to make 7deg feel like 5deg.
Of course results will vary with the angle.
For example to make 12deg feel like 10deg, I would need to loose 12kg.
Dragging 58kg up a 12deg slope is same work as dragging 70kg up 10deg slope.
Unless already overweight (and since you are a cyclist you arent right ) this is one