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Looks to me like there is an issue with the road there that is not evident on the video. Everyone is having the same problem on the same spots.
 

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Hrm, can't believe a motorcycle magazine hasn't done an article on this yet. If anybody sees one, please link it here....

mcanlas, let me explain.

1.) A high side is a temporary loss of traction, regained too quickly, which flicks the bike with enough force to de-seat the rider. The old saying: "If you're bike loves you very much, leaves you, and comes right back to you, you've just high-sided" is very true. :p let's look at the factors.

2.) The operative wheel in a high side is usually the rear wheel. It is the locomotion wheel - providing forward momentum, directly linked to the power plant (engine). On high power bikes it is easy to do a burn-out with the front brake locked, even with all the bike and pilot's weight on the rear wheel.... When the bike is leaned over in a turn, it requires even less power to spin the rear wheel. The tires are the only things keeping the bike on track, fighting centripetal force. If a tire spins, it is no longer holding traction, making it slide, and the centripetal force carries the sliding wheel to the outside of the turn. The rider realizes this and chops the throttle, which immediately slows down the tire to a speed of where it can grip the road again, and locks the bike back in line so quickly that the bike is "flicked" back into it's original track. The flick is so intense that it can throw riders a hundred yards or more away from the bike. Usually it's just enough to buck the rider off the bike....

3.) Tires, especially today's uber sticky sport compound tires deform to hold every microscopic crevice, ravine and bump on the road to gain maximum traction. However, they only do this in a very small temperature range. Why so? These tires are made to handle the breeding of the sportbike - putting serious horsepower down on the road into forward momentum. To be able to stay in one piece, the rubber is formulated to keep structural rigidity at a certain temperature, a HIGH temperature, it's what happens when go screaming down the race track on 110F day at 200mph... However, the rubber formulas are NOT advanced enough to provide the desired durability, and grip, across a wider range of temperatures (ie, less than 170F - cold as far as race tire temps go). So, at lower temps, super expensive sticky tires are worthless. All of these guys are running those tires, but the road does not allow enough speed (and therefor force) to enter the tires and warm them up to optimal temperature, which means they're more like skates than tires. Hard, rigid, and not grippy at all.

4.) The road - it's tight, twisty, and a lot of fun. More suited to a 450cc super moto or Ninja 250 - smaller bikes for a tighter track, but bigger bikes can play too. Unfortunately bigger bikes are designed to run faster and farther and everything on them is designed for increased speeds... The suspension, tires and brakes are all optimized to run ABOVE 80mph clear up to 180mph or so.... As the road gets tighter, F=MA (Force = Mass x Acceleration) gets in the way. The bike and rider is of a specific weight (M). The speed is low (A), which means that the tires have to deal with a Force much greater than they are able to at that moment. Throw them on a track for a few hot laps, or put some tire warmers on, and they're probably work better, but not under these circumstances.

5.) Rider ability - How much to twist that throttle. On the big bikes, a 1/8 of a turn on the throttle tube could be difference between 25 and 50hp, all while having covered 20 feet and a split second. There is no way the tires can keep up with that. Top level racers can open/close their throttles in increments as small as 1/128th of a turn - they are that practiced. Most of these guys did well, not getting way out of line, but they still have a little way to go....

I hope this gets the discussion started, sorry for the book, but lots of factors happening here...
 

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very informative. great info for when i get into conversations about physics. But here is a noob question. If ever I enter a corner too fast, how do i slow down if i am afraid the rear tire will slip if rear braking and cause a high side when it regains traction, and cutting down on the throttle is considered chopping the throttle? I know downshifting is not an option, which I learned the hard way on a 600 yamaha.... and thus here I am on a 250 and loving it.
 

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There is a massive difference between chopping the throttle and letting off the throttle....

Also, rear-brake modulation - practicing braking is your real answer. Go to a parking lot and run the bike up to 40mph in a straight line, and brake as hard as you can. 1.) with both brakes. 2.) with just the front brake 3.) with just the rear brake. This is all in a straight line, so you can build a stronger foundation of brake feel/feedback.

BUT, what do you do when you enter the turn too hot? Keep the throttle where it is, and lean for your life! You'll pucker, but you'll probably come out of it just fine.... You can also back off the throttle just ever so slightly, BUT - and this is a HUGE BUT....

As the motorcycle is going around a corner it requires a certain amount of momentum and centripetal force to maintain it's lean angle.... If you decrease that force the bike will want to fall INTO the turn. If you increase that force, the bike will want to stand up and run wide. SO, be VERY weary of how much throttle you decrease. Chopping the throttle might end in a high side, but more than likely, it will end up in a very dirty low side. A slight throttle decrease will probably end in a saved, but otherwise botched turn....

However, this is all WAY too much to be thinking about in the few moments as a perceived immanent crash is staring you in the face, so just remember this: Freeze the throttle where it's at, and lean like you've never leaned before....
 

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mcanlas said:
finally a place with intelligent people. the comments on the youtube video (and all of you tube actually) are just insane.
http://www.youtube.com/watch?v=66ZtZ8m63qY&feature=youtube_gdata_player

I agree, and gonna sound newbish again but I thought a bight side would be a loss of traction as you guys explained so the back tyre swings out and the momentum wants to go forward and flicks the bike over onto it's other side and then flicking off the rider
 

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A high side starts with a loss of traction. It ends when the rear wheel regains the traction. Ever seen stunters "drift" a motorcycle? - Icon has a great new marketing campaign - Drift II which exhibits this. In any drift, you are loosing traction. Also, in skids. Both are examples of loosing traction which does not end in a high side.

The rear wheel needs to regain traction to "rip" itself back in line behind the front tire. As it's yanked back in line is when the flick happens, and if the flick is hard enough, to fling the rider off.

High sides are becoming more commonplace as tire technology keeps improving and the line between traction and no traction becomes thinner and thinner.
 
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