Exploring Fork behavior on initial lean turning

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Last year while at Laguna Seca it was really amazing to watch how they use the rear tire to steer, As they come down to the corner and under hard braking they are sliding ever so slightly, some riders more than others. I have heard riders say this helps to position the bike for the corner. Don't know just how much it really helps but some do say it does. But I would think as you go into the corner the forks would start to compress, at what point i don't know, but forces are trying to pull outward in the corner as i have on a few occasions found out while sliding, LOL. Watching these guys really is something I think everyone should see at least once in there life, Sad I will miss this years race as the Norton Rally in Wyoming will be about that time. Going to that will be just a little more fun! Have a great day guys. Riding to the Vintage bike meet today. :mrgreen:
 
a. when bike is tipped off vertical then less vertical mass on fork springs
b. when rear tire powered up its torque unloads fork springs
c. phase 3 leaned straight steering turns lifts front tire with no throttle applied
d. phase 4 leaned turns straight steering lifts front tire with hi throttle applied
e. current best handling cycles/pilots in the world need special places to just
barely taste these states instead of about any place and time bored with life.
f. budhic 5th way w/o flight hesitations of backward G's slalom skiing >>>

[video]http://www.youtube.com/watch?feature=player_embedded&v=XCGaQMgkzw8[/video]
 
Sad I will miss this years race as the Norton Rally in Wyoming will be about that time. Going to that will be just a little more fun! Have a great day guys. Riding to the Vintage bike meet today. :mrgreen:[/quote]

Had not considered missing Laguna Seca due to the Wyoming Rally. You're right about the timing. I stopped going to Laguna Seca a few years ago anyway due to the high cost of motels that week....ridiculous. See you in Wyoming. Look for my license "ILLF8ED" on a red '72 roaster.
 
The cop in the video is trying to keep dive and lift to a minimum as stuffs coming at him nonstop. Even In the faster parts he initiates the next turn at the exit of the previous turn to save energy. Like fast woods riding. I think if your riding 50 70 mph through winding curves at more or less steady throttle the forks may rise. I remember that from an r100 bmw. If you want a real thrill ride my 500 2 stroke with no engine braking. You'll be praying for just that right initial amount of fork dive or attitude adjustment thats so easy to get with the throttle on 4 strokes. Friendly front brakes become important. With no change in velocity or center of gravity countersteering will extend forks because of trail at contact patch but I don't think your finding that with feet on hte axle. When you ride logging roads I bet you don't see any rise because you have to shift weight forward to get grip feedback. Grippy pavement makes for a larger variety of possible inputs to get around a turn at less than go to jail speeds. Talent level changes everything.

Make up a position sensor for fork travel so you dont influence things with weight forward like a stunter. An old lawn mower cable one end zip tied to fork slider, housing zip tied to lower triple, housing cuvred over clocks and other cable end dog legged through a needle with a simple pivot. Fork travel gauge. The more spirited the ride the more dive you'll see.
 
The cop in the video is trying to keep dive and lift to a minimum as stuffs coming at him nonstop. Even In the faster parts he initiates the next turn at the exit of the previous turn to save energy.
He's letting-making the bike fall into the ground but missing it automagically once the sense of balance and bike reaction engrained. As he lets-makes bike initiate a fall over on its own, the fork expands.

Like fast woods riding. I think if your riding 50 70 mph through winding curves at more or less steady throttle the forks may rise.
My average commuting Gravel Travel is 50-70 in the more open winding curves w/o slip sliding, hardly at all. In this moderate skill-speed condition, one better only steer by tipping the forks sideways to tip bike into direction desired but not trying to put in counter or straight steer, just let the forks road follow either way they want, while dampening out the fork snatch outs. Forks expand on each initial new lean-direction or correction. Forks compress some once lean is set and then some more on relieving lean to more upright stance, unless throttling up away from apex as is about universal then rear thrust lifts front suspension. Watch any off road fast stuff to see they try to keep front unloaded and also straight steering naturally. Camera on helmet that views forks show this the best, they tip forks in direction needed and they straight steer by themselves. Fast off roads can do this because they are in such little traction the bike is litterally falling out from under on rear slipping but front straight steer counters with hi side force to rear stays mostly hooked up and bike mostly upright.

I remember that from an r100 bmw. If you want a real thrill ride my 500 2 stroke with no engine braking. You'll be praying for just that right initial amount of fork dive or attitude adjustment thats so easy to get with the throttle on 4 strokes.
Now there's a groin tightening image! I can imagine what happens if the splash of suspension and throttle response don't click... I was forced to give up on brakes on loose stuff for any slowing that mattered in time of crisis or hot rodding in favor of first reflex to steer wildly - all the way sideways at times so both tires dragging speed down in one direction while rear spun some converts thrust into a new direction, when the braking slide vectors stops bike should pop up on its own w/o full hi side upside down. A really neutral bike will slide w/o changing lean angle, others low side instantly or swap ends till rear snags a hi side, damhik.


Friendly front brakes become important. With no change in velocity or center of gravity countersteering will extend forks because of trail at contact patch but I don't think your finding that with feet on hte axle.
I have been tested and corrected by THE Gravel, to point I can not even grip the front brake in a crisis, my hand instantly feel like a witch given a glowing red hot rod to see how long she blisters to let go. Brakes off road are for delicate conditions not slowing up for going fast, then brakes only change lean angle real fast or which end of bike is pivoting out first.

When you ride logging roads I bet you don't see any rise because you have to shift weight forward to get grip feedback. Grippy pavement makes for a larger variety of possible inputs to get around a turn at less than go to jail speeds. Talent level changes everything.
Boy Howdy not me No Sir Ree Bobeedoo, I get back on bike to unload forks and try to be on power much as I can to unload forks, one so they don't rudder into the rough texture overwhelming the rear aim, or two to clear rough stuff by helping unload the front to float over instead of skip out snatch out bing bam boom. Putting ones feet on the axle or the sliders moving with axle is best way to feel the truth of the matter but a mark and a video camera would show the rest of the world.
Race bikes don't have much travel so hard to see in race video.

Make up a position sensor for fork travel so you dont influence things with weight forward like a stunter. An old lawn mower cable one end zip tied to fork slider, housing zip tied to lower triple, housing cuvred over clocks and other cable end dog legged through a needle with a simple pivot. Fork travel gauge. The more spirited the ride the more dive you'll see.
If ya put a stick on the slider that stuck up near grips you could watch it try to poke ya on initial lean overs. But consider the point of physics you make, if my feet out over the sliders adding some front wt. bias my forks still expand as soon as I initiate a turn either by body english only or by some fork turning one way or the other.

All the above proves to me that the front is only needed to help tip the rear or otherwise just not get in the way of the rear angle and thrust Ruling The Roost so it never ever overwhelms rear by a conflict of traction aiming.
 
IMO, Hobot is correct.

Typically, at initial turn in, you (consciously or not) countersteer. That is, if you are turning right, then the wheel - momentarily - actually points left, slightly, to initiate the lean.

At that moment of lean initiation, the forks do actually extend as the front wheel is steered out and away from the bike's path. Once the lean angle is established, and the tire is rolling on the smaller circumferance of its side, then the countersteer is reversed, and the forks are re-compressed as they take up the cornering load.

I too have seen daylight under racers' front wheels as they initiate turns but I noticed it when they were in a transistion from a left to a right and saw it as they were "going over the top" as they unloaded the left turning force, and flipped the bike to the right. It seemed like the bike was rebounding off of the left force as it went over the top. I saw Rossi crash at Indianapolis, in 2009, between turns one and two; it seemed as if he just flipped the bike too hard, flipped it right off its wheels, left to right, too quick, too aggressive in the transition. I saw daylight under his front wheel. Watched the video when I got home, confirmed it, I saw the daylight again.
 
Educational feedback John. I know exactly why how and what these racers are doing to catch front air on sharp direction changes but their bikes only allow it in special places and even then are so freaking splashiing with resonating frame and tire harmonics on tricky torque curves with wind gusts they are too unpredicable to pull off each and every time. John gives perfect example why I call them all corner cripples. Their CoG is so high that if ya fling on em too hard they pivot on that CoG instead of tire patch and lift both tires horizontal - for a very short flight time that can be long enough to take a line of riders out with them.

One only needs to use counter steer to help speed lean of bike when rear not so powered up the bike don't tend to fall over on its own, in which case it will straight steer, same as hand off just leaning body English - eventually that low force will lean bike into desired direction, forks following.

If you are in a sharp counter steering state and change fork direction fast enough into straight steer the bike will tend to hi side by lifting front first. Done much harsher on a corner cripple it can take pilot down. Done on a Neutral power handler the hi side is like wrist twitch triggered power steering save directed by eye ball point of aim.

Its kind of hard to find good video to demo the difference of riding in grippy countersteering states vs ridding on a loose rear you can't lean on much or ZIP, but that don't mean ya have to go around slow, just differently. I paid $3000 to Code to find out if pavement ridden so fast its as loose as Gravel or snow to find yep it is > if can break past scare to over power over lean and over steer right out of normal control w/o loss of control. Lots of examples here of 'reversed' fork action sense below. There is a reason MX bikes have small front brakes.

[video]http://www.youtube.com/watch?v=NOT2ytYB1wI[/video]
 
Check out this dizzy groin tightening wet racing in slow motion wonder video. Very interesting thing revealed by wet traction wheelies, hot dog.

[video]http://www.youtube.com/watch?v=eBUfN0MnfJE[/video]

This one answers my question if a unicycle can slide, yep they can, at least on balloon tires. If a tire is sliding its dividing up its traction total by vector subtractions, which is still fast fun on slow mo video
[video]http://www.youtube.com/watch?v=fmBACCK49XA&feature=endscreen&NR=1[/video]

Love seeing them balloon tire dances just not right on top of em thank you.
[video]http://www.youtube.com/watch?feature=endscreen&v=Ha2fy85vCTE&NR=1[/video]
 
edgefinder I love and hate your handle, just in case ya thought you'd not left a nice impression of a naughty ryder. You'd have found the single best video of exactly what I'm into on my Ms Peel, on THE Gravel or dry pavement. I've still got to get down wet tarmac so this video is by far the most educational sensational and mind numbing reassuring for me to see and take in. YUM! What yo'all may see as so fantastic, certainly is, as far as an over powered balloon tire waddle'r wheelie prone superbike with space cadet pilot on it, but exactly demo's why I call that combo corner crippled. The Only Advantage Ms Peel can have agianst such wonder that leave me trembling ok, is she does not exhibit the tail wag in those skipping out or drifting crossed up STRAIGHT STEERING! Watch again very close to see how only STRAIGHT STEERING is saving his bacon as he gets loose and drifts and then how he snaps out of drifts. I will have to study this many times to pick apart everything going wrong with his aim and his bike behavior. I don't know if I could handle his type bike like he does in the wet ok, many because I have on dry track so no longer have faith in that level of commitment on such unpredictable bikes now I've re-gained will to live last few decades. Anywho if Peel can't take on the likes of this level of handling and speed then she is just so so half fast quaint push rod clunker that wastes tires going no where harshly thrilling.

When ya do this slip drift routinely ya get a bit bored so create games like dancing bike to rock and roll beat using mainly your butt muscles to wag the tail. Was doing that once when a deer leaped out at me catch in corner of eye, twisting bike diagonal on its center of gravity with a down beat then catch the snare durm part on the twitchy jerking snatchy recovery before fenece and ditch a bike length away. I think its was Stair Way to Heaven or Radar Love. I am programed to my fragile spinal column bones not to slide and drift, just jerk and twitch.
 
Lots of insane video to learn from the easy way. Watch an oil patch take down a handful of riders and THE Gravel too.

[video]http://www.youtube.com/watch?feature=endscreen&v=_08p-414uGY&NR=1[/video]
 
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