Just curious about the "physics" of it.

Is it that when the rear tire is out of line with the bike, when it re-connects, the angle of the wheel to the rest of the bike causes it to suddenly yank itself back under the bike, standing it up in an abrupt motion?

That is what it looks like to me but I :dunno. I am curious as well it's a good question:thumbup Hope someone can answer the question for you better then me

 

The tire doesn't yank it self back under the bike. When the tire regains traction as it is moving sideways, it then acts as a hinge and the momentum of the bike moving sideways then rotates about that hinge joint, standing itself up (and over the other side) violently, and off you go. Simple as that.

 

O ok I see:thumbup it makes sense now that you explain it. Not my question but thanks for the answer because I was curious as well

This one shows what really happens well ...

http://www.youtube.com/watch?v=CCkhAq9rztQ&feature=related

Yeah I see what Kmac is talking about in that video. Good post Thanks:thumbup

 

This one shows what really happens well ...

http://www.youtube.com/watch?v=CCkhAq9rztQ&feature=related

 

Ah, so it's the same kind of force at work regardless of how sideways the bike gets. Thanks.

 

Nice video - shows an excellent highside

 

trust me . . . there is no such thing as an excellent high side :hammer: :lol

 

You are asking 2 questions.

The first - a highside due to braking is due to the front and rear wheel getting out of alignment during the skid. When the bike regains traction, the wheels are not aligned so they cause a torque that chucks you off.

The spinning / then hookup highside is due to the spinning wheel gathering kinetic energy while it spins. When it regains tracktion, the wheel sends that energy through the chassis causing the bucking/throwing motion of the bike.

 

Nice, uh, terminology... And spectactular break-down of the general laws of physics...


IN A HIGHSIDE...

- The back tire looses traction, causing the bikes rear tire to shift to the side and placing weight outside the C of G.
- Once this occurs the bikes tires are traveling across 2 axis, instead of one.
- When the tire regains traction, it loads-up the suspension to its max.
- Because the rear suspension is loaded (unlike the front), it applies more force to make the bike follow its path instead of the front.
- instant ejection off the saddle is the recurring conclusion to this physics leason...

Kinetic energy is a bitch sometimes...

:lol

* EDIT - Juice, you hadn't replied when I started mine... You're on the right track though...

 

I can tell you it hurts. Mine cost me three months off work and four surgeries to the hand and foot.

 

I don't know if anyone has touched on this yet, but it is also due to the action of the rear shock. When the shock compresses and loads up, then decompresses it throws the rider into the air. How high you go is a factor of your inertia, the compression of the spring, the speed you were travelling and how quickly the bike "corrected itself".

I had a BIG highside last weekend on the YZ450. Not fun, at least until the pain stops and you realise you are still alive. :lol

 

I can show you what it looks like from a riders perspective....I was able to hold on and not go down, my helmet hit the camera and knocked it sideways.

http://videos.streetfire.net/video/Turn-6-highside-almost_215727.htm

 

I dont wish it on anyone, but it really is an amazing display of physics. I must weigh about 270 and I was flung off like it was nothing... it happened to me about 2 years ago and all I remember is giving it gas, then looking at the stars. It was instantaneous.

i've got a plate in my right arm to always remind me to be smooth on the throttle from now on.

 

man u guys are getting way to deep into the facts here.... just look at causation, titties on the side of the track does it for me

 

Keep it simple, let JOSHE HAYES illustrate what causes a high side

http://www.youtube.com/watch?v=M335eycAjKY&eurl=http%3A%2F%2Fwww.bikeland.org%2Fboard%2Fviewthread.php%3FFID%3D35%26TID%3D47801%26set_time%3D1244776197&feature=player_embedded

 

I am thankful to have only experienced the low side crash so far. But I know pushing it out of a corner at the track is eventually going to result in a high side. I just hope the bike doesn't land on top of me. I believe that's where a lot of high-side fatalities occur.