We took Mark back to the days when he was a physics teacher and used video and photos of the BFC canyon gap to do a rough analysis of the kinds of forces the riders (and their bikes) are facing.

Caveats from Mark

A LOT of assumptions have been made and not inconsiderable guesses about the variables. That said, I think we get somewhere close to an idea of the forces involved in the end. Areas that I am cloudier about that could use some refining are things like the time it takes to compress a fork through its travel, which plays an important part in the final calculation of the forces dissipated and felt by the rider. I'm very much hoping someone with more time and accurate variables could refine all this to get more accurate answer.

Values I've attributed to variables:

• Deformation time (impact to fork/shock) - 0.1 s

• Tom - 70kg

• Bike - guess at 13 .5kg

• 162mm rear/ 180mm front shocks

• Tom's BFC gap22.5m gap/1.6s airtime = 14.06m/s

Calculating the velocity at impact

Although the rider is on a parabolic path and travels some horizontal distance, this is almost a red herring as what we are really interested in is the vertical velocity at impact. That's calculated by using the gravitational force from the top of the parabola to the impact point. ie. freefall velocity from maximum height of the rider to the landing point. In other words we need to calculate how high he gets and then how far down he falls. That will give us the impact velocity.