How does the lever arm change if you decrease the angle of the force?

The lever arm could decrease or increase depending of the initial angle.

Explanation:

The lever arm d is calculated by:

d = rsin(θ)

where r is the radius and θ the angle between the force and the radius.

So, the increse or decrees of d depends of the sin of the angle θ, if the initial angle is greather than 90° and the angle decrease to an angle closer to 90°, the lever arm will increase but if the initial angle is 90° or lower and the angle decrease, the lever arm will decrease.