**Chaptor 1 : How much force do you need to push up the dropped Monster?**

How to calculate the amount of force needed to pick up the bikeLet’s use my S4R as an example.

The dry weight of S4R is 181kg (399 lb.), according to Ducati.

Add fuel, oil, coolant & battery,...

let’s say it weighs 210kg (463 lb.), and it’s dropped.

How much force do you actually need to pick up this bike?

stage 1

This is your starting point.

The bike is dropped, laying down on the ground,

leaning on the frame slider.

The “lean angle” of the dropped bike 𝜃 is approximately 70°.

(In other words, it’s 20° from the ground line.)

L1 : The gravity is pulling the bike toward the earth, with the amount of 210kg(463lb.)

Force L1 can be divided into L1’ and L1”

L1’ can be calculated as...

L1’ ÷ L1 =sin 𝜃

L1’ = sin 𝜃 x L1 = sin 70 x 210 =197.34 kg

So, if you apply the force,

which is more than 197.34kg (426 lb.),

in exactly opposite direction of L1’,

you can push the bike up.

Let’s call this force L2.

Now, remember what I said in the first video?

“think it as class 2 lever”

r

When you push up the motorcycle, you don’t push it at the center of mass.

You apply the force much higher place, near the top of the motorcycle.

A1 : load arm length (Distance between the fulcrum and Center of mass of the bike)

A2: Effort arm length (Distance between the fulcrum and the point where you apply the force)

On S4R, A1 : A2 ≒ 2 : 3

E1 : Force needed to push up the bike

E1=(L1’ x A1) ÷ A2

=(197 x 2) ÷ 3

= 131.33 kg (290 lb.)

So, you need to apply roughly a little bit more than 131 kg (290 lb.)

of force, at the top (near the top) of the bike.

... to be continued