DH Mt Bike - Optimizing Drop Landing Ramp Profile

  • Context: Undergrad 
  • Thread starter Thread starter erobz
  • Start date Start date
  • #31
berkeman said:
I think some videos of your riding group are needed here... :smile:
I don't have youtube for videos, but maybe I can get some still frames. :smile:
 
Last edited:
  • Like
Likes   Reactions: berkeman
Physics news on Phys.org
  • #32
haruspex said:
Professional cyclists achieve astonishing acceleration but don’t flip over backwards. It would seem perverse to try to do the lift entirely by pedal power when it would be so much easier to get a start using the body’s inertia. No doubt pedal power comes into play thereafter.
To me personally it feels like you are initiating pedaling (in a high gear), while leaning back simultaneously. It puts a "smooth" tension in your arms.
 
  • #33
haruspex said:
Does that mean they push down on the handlebars while the front wheel is still grounded, throwing the body up and back, so that they can then pull up on the handlebars when the front wheel leaves the ground?
Things you could do:

- Start with your CoM as high as possible.
- Once the front wheel looses support, drop your body down, so the CoM of bike+rider accelerates downwards.

This reduces the ground support force on the back wheel during the single wheel support phase (it becomes less than m*g), and thus the torque that this support force creates on bike+rider around their CoM.

If you additionally drop body backwards, then the CoM also moves back, which reduces the lever arm of that support force on the back wheel around the CoM.

This seems to be what the riders in the videos are doing.
 
Last edited:
  • #34
@berkeman I'm in the grey shirt. This is Mt. Creek Bike Park in New Jersey.

1775062506058.webp


This is me coming off of a pretty nice sized drop.
1775062534964.webp

And landing!
1775062591740.webp


We are all in our 40's and 50's. I only get out to do this 1 to 2 times annually. Otherwise we prefer to ride technical XC (Enduro).
 
Last edited:
  • Like
Likes   Reactions: berkeman

Similar threads

  • · Replies 28 ·
Replies
28
Views
2K
  • · Replies 3 ·
Replies
3
Views
3K
  • · Replies 10 ·
Replies
10
Views
3K
  • · Replies 21 ·
Replies
21
Views
6K
  • · Replies 1 ·
Replies
1
Views
5K
  • · Replies 13 ·
Replies
13
Views
4K
  • · Replies 2 ·
Replies
2
Views
4K
  • · Replies 4 ·
Replies
4
Views
3K
  • · Replies 1 ·
Replies
1
Views
4K