What went wrong here? - Wrist Twisters
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Old 09-05-2019, 02:47 PM Thread Starter
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What went wrong here?

After I watched this, I'm not sure I agree with what the guy's saying. He's saying the guy had lean, but because the lean came from a lower point, it wasn't the same?

Seems to me that if the motorcycle leans, it leans and it doesn't matter if the cause of the lean is from your butt or your shoulders, it's still a lean. So assuming the lean angle is the same, what difference does it make if you cause the lean from mid or upper body?

Also, he seems to say that counter-steering would have prevented this, I don't understand, exactly what was they guy supposed to do, push downward on the left side of the handle bars so that the front wheel turns towards the inside of the turn?

I don't really understand this.


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Old 09-05-2019, 03:29 PM
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To me, he is riding "crossed up". Dirt style. He causing the bike to lean to over by keeping his head centered on the bars with his butt hanging off. Works well to accentuate lean in dirt because the tire digs into dirt enhancing traction. Were he to push down on his right leg put his helmet over near his inside mirror, counter weight the bike, it would stand up more and he could counter steer with lean angle to spare. Keith Code power steering style. He's out of lean angle, far too soon. He entered too shallow as well. I think he panicked, didn't look through the turn and target fixated on the shoulder of the road. Once off the road he had target fixation again on the treeline and ditch and drifted to the right. He could have drifted left had he had the mind to do so. Half a cheek off is a good start but you lean, so your bike doesn't. Better suspension when the bike is vertical, better traction too. 45 degrees is about all you get, use it wisely.

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Old 09-05-2019, 04:18 PM
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Quote:
Originally Posted by KarlJay View Post
After I watched this, I'm not sure I agree with what the guy's saying. He's saying the guy had lean, but because the lean came from a lower point, it wasn't the same?

Seems to me that if the motorcycle leans, it leans and it doesn't matter if the cause of the lean is from your butt or your shoulders, it's still a lean. So assuming the lean angle is the same, what difference does it make if you cause the lean from mid or upper body?

Also, he seems to say that counter-steering would have prevented this, I don't understand, exactly what was they guy supposed to do, push downward on the left side of the handle bars so that the front wheel turns towards the inside of the turn?

I don't really understand this.

As long as you have enough lean angle to make a corner for the speed you are going, on the line you are going, in theory it doesn’t matter how you get the bike leaned enough.

But in practice you technically should want to minimize the amount of lean angle you are using as this gives you more margin for error or emergency situations. The more you are leaned the less options you have for emergency maneuvers/reactions.
And if you are taking a corner at close to the maximum speed a particular bike can handle (this should not be the case for the vast majority of us and especially on the street) then you theoretically you would be using all of the lean angle available and using body position increases the amount a bike can turn at any given lean angle.
Also, another reason to hang off a bike while racing/track riding is it increases view/vision to see through the corner.

IMO for “safe” aggressive street riding (always in your lane including head never over the center line, and at 70-80% (leaving at least 20% for error/emergency)); you really shouldn’t have to do a lot of butt positioning and hanging off the bike/dragging knee.
Upper body positioning does a lot more to help decrease lean angle while taking the corner at the same speed as sitting upright to make the corner.
The human head weighs about 10 pounds and helmet weight also, plus the weight of your shoulders/torso. They are also further up and out from the center of gravity of the bike, where your butt is much closer. So shifting the upper body correctly has a much bigger impact than the butt on decreasing your needed lean angle to take the corner at a given speed.

That being said there are times when I ride “lazy” aggressive. I’ll remain upright and just use counter steering to take corners at fairly high speeds. The bike will handle it just fine but I am using more lean angle than would be needed for that particular speed had I shifted my upper body over. Thus I am increasing the relative risk should I need to make an emergency maneuver.

To answer your last question, had the rider used counter steering and pushed harder on his left handlebar to increase his lean angle he likely would have made the corner. But he probably froze up due to his experience level or fear of leaning the bike further than his comfort level.
And it appears he makes a common error of shifting his butt to the left but in the process shifts his upper body to the right, instead of left. So he is actually increasing the lean angle needed than had he just remained completely upright and used counter steering only to make the corner.

Edit: I just rewatched (watched through to the end) his lean angle was a bit more than I initially thought but still appeared to have some lean left, not sure he was at the max.
However due to his upper body being way to the right counter steering through the corner may have been more difficult in that situation than had he been upright or just slightly to the left. Armchair quarterbacking had he been upright and not leaned right I think counter steering likely could have got him through.
And had he had his upper body been completely positioned correctly to the left wouldn’t have been any problems.

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Old 09-05-2019, 05:05 PM
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I apologize for the typos in the last post. I made an edit.. must have hit undo before posting. That was to read: He is causing the bike to lean over by... Also wanted to add why one might cross up to accentuate the lean in dirt. Itís about digging in for traction to a point.. itís also- the butt slide replaced with a dropped leg and a drift, sliding to change your turn in. Tightening your radius. Not so much a move for the street...
Dan the fireman said grab an handful of brake.. that wonít work well anywhere... just donít panic and use the brakes. I had a 74 cb360 with road tires, as my first bike (at 11 ...Dad...he got me a 125 Honda 3 wheeler for my third birthday..), I rode the cb360t in nothing but blueberry fields and dirt roads for years. Grass is not ideal, but using your brakes in grass is certainly doable. Front and rear, as normal- same rules apply. Did it for years.. I just learned that way... Never wiped out. Definitely should have.. Iíve already driven the 919 through our field.. I followed my dad around on his 8n...
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Old 09-05-2019, 05:07 PM
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Here is a Motovlogger video that shows him riding using mainly upper body for his cornering.

A kinda boring video but if you watch at 9:30 (camera angle is from behind) for a couple of minutes you will get the idea. He doesn’t do much shifting with his lower body, doesn’t hang his lower body off the bike, and most of his body positioning is upper body while cornering.

https://youtu.be/F8RlU1C3vm8

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Old 09-05-2019, 06:06 PM Thread Starter
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So does everyone agree that he had enough lean angle?

If that's the case, then what went wrong?

To me it looks like the momentum was pushing the bike outwards and he didn't turn the bars slightly to the left. IDK if you'd call that counter steering or not, but seems like a few degrees turn of the bars to the left would have solved the problem.

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Old 09-05-2019, 06:19 PM
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I think he had too much lean angle and should have entered from a different lane position. If he leaned left- which he is not, he is crossed up- essentially leaning right. Butt left -head right like / forcing the bike to lean left, if he leaned left- upper body or whole body, the bike would stand up to compensate. He would be entering the corner with less lean angle he could then push left to counter steer, the bike would lay over and all is well. I weight the outside peg, but that is preference. I think he gave up mid corner. Look left, Lean left, push left, go left. A line through his spine points right.
He may have had enough ground clearance to push left with his hand and make it, but his entry angle leaves less room for error. Pushing down with his right foot and pushing and leaning left would be my choice.

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Old 09-05-2019, 06:19 PM
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Per recognized motorcycle dynamics authorities Cossalter, Foal and Bargy, here's something to ponder in terms of the thread so far.
Paraphrased for simplicity.
For a steady state turning, the equilibrium is determined by the combination of speed, radius of turn and the combined Centre of Gravity of the Rider and the Motorcycle, which then dictates the steady state lean angle.
(Emphasis on the COMBINED Centre of Gravity of the Rider and the Motorcycle)
Relocation of the combined C of G, affects the required lean angle in order to maintain the same radius of turn at the same speed.
For example, elevating and shifting the C of G inboard, results in a reduced required lean angle.
Or, elevating and shifting the C of G inboard, while maintaining the same lean angle, will allow for greater speed for the given radius.
Or, elevating and shifting the C of G inboard, while maintaining the same lean angle, will allow for a tighter radius for the given speed.
Here's a real world example:
A 919 set up tall for track days, with a rider who gets off well to the inside and keeps his head up, will be able to use less lean angle to avoid dragging or running out of tire, and/or choose to go for a tighter radius, or higher corner speed, or some combination of the latter two.
Then consider ones personal distribution of body mass from head to toe, and how it's located by your body position at a track day.
Hence getting off to the inside as much of your weight as you can.
Just look at old school superbike riders, but when you do that, keep in mind the limited tires of the day, in particular the number of effective degrees of grip they had, nominally 45 degrees.
Counter to that though, are today's racing tires, allowing insane leans of up to 65 degrees in MotoGP today.
With those kinds of lean angles, it is not possible to get off like the old days, as there are not enough degrees remaining to fit in such a body positioned rider.
So the riders have had to adapt to the physical space between bike and pavement, hence the bike side hugging style seen today.

Anyway, the video can be seen in a different light, given the above physics.

Back to setting a 919 up tall for track days.
This also reduces the leverage effort to muscle the bike over, and it's very noticeable.
But it also increases the leverage required to muscle the bike back up - but I haven't found that to be as noticeable.
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Old 09-05-2019, 06:36 PM
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Quote:
Originally Posted by KarlJay View Post
So does everyone agree that he had enough lean angle?

If that's the case, then what went wrong?

To me it looks like the momentum was pushing the bike outwards and he didn't turn the bars slightly to the left. IDK if you'd call that counter steering or not, but seems like a few degrees turn of the bars to the left would have solved the problem.
Kind of.

As was stated in a post above, the lean angle needed is a product of several factors combined. Had his line selection and body position been better he would have needed less lean angle than what he had to make the turn easily.

But taking it from the point where he had his O Shiiit moment. What you stated is what he should have done.
Except not exactly turn the handle bars the left, but push downward harder on the left handlebar (counter steering).
However, this would have caused more lean angle, but that additional lean was necessary (in his predicament) to make it through.
Counter steering creates lean angle, you can’t do it without causing lean. The harder you push down (in his case he needed to push a bit more) the more you lean.
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Old 09-05-2019, 09:44 PM
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Quote:
Originally Posted by mcromo44 View Post
Per recognized motorcycle dynamics authorities Cossalter, Foal and Bargy, here's something to ponder in terms of the thread so far.

Back to setting a 919 up tall for track days.
This also reduces the leverage effort to muscle the bike over, and it's very noticeable.
But it also increases the leverage required to muscle the bike back up - but I haven't found that to be as noticeable.


My friend is the one who recorded this video. He wound up breaking some ribs, his hip and his collar bone. The rider who crashed sold all of his gear last week and has given up riding. =(

From my measurements, the 919 grounds out at roughly 50 degrees of lean in stock form with the hero blobs removed. It's significantly less than what the average track bike achieves. How exactly did you set up the 919 to be "tall?" Or rather, what are some go-to mods for better track performance? To be honest, I don't believe my honda with stock suspension and 60k miles could even handle the increased energy from higher lean angles. It already feels like it's being twisted into knots if I'm not ultra smooth. God forbid I hit a dip mid corner, the rear shock pumps a good 3-4 times before it settles out, and thats with the rebound full hard. My guess is a cartridge kit, a good rear shock and a good set of rearsets + trackday rubber would greatly benefit the bike. Then again, for the same price you can just buy a track-ready sportbike which will easily outperform what I just suggested.
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Old 09-06-2019, 12:30 AM Thread Starter
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My friend is the one who recorded this video. He wound up breaking some ribs, his hip and his collar bone. The rider who crashed sold all of his gear last week and has given up riding. =(

From my measurements, the 919 grounds out at roughly 50 degrees of lean in stock form with the hero blobs removed. It's significantly less than what the average track bike achieves. How exactly did you set up the 919 to be "tall?" Or rather, what are some go-to mods for better track performance? To be honest, I don't believe my honda with stock suspension and 60k miles could even handle the increased energy from higher lean angles. It already feels like it's being twisted into knots if I'm not ultra smooth. God forbid I hit a dip mid corner, the rear shock pumps a good 3-4 times before it settles out, and thats with the rebound full hard. My guess is a cartridge kit, a good rear shock and a good set of rearsets + trackday rubber would greatly benefit the bike. Then again, for the same price you can just buy a track-ready sportbike which will easily outperform what I just suggested.
Wow, small world! Sorry to hear all the damage done and I hate to see someone cash out because of a mistake that anyone could have made. I've made some mistakes too and they can really hurt, but I consider myself very lucky that after 10 years and MANY miles, I'm nearly 100% intact.

I think maybe we can at least all learn a bit from this.

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Old 09-06-2019, 01:17 PM
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Twist of the Wrist II pretty much describes the poor guy in the DDFM video above. The video is a bit dated, but the information is not. 11:10.00 is the S.R. discussion. (Survival Reaction). Worth the watch if you can get through the acting...

Twist of the Wrist II - Keith Code
https://youtu.be/pN91HM16TFY

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Old 09-06-2019, 05:36 PM
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Twist of the Wrist II pretty much describes the poor guy in the DDFM video above. The video is a bit dated, but the information is not. 11:10.00 is the S.R. discussion. (Survival Reaction). Worth the watch if you can get through the acting...

Twist of the Wrist II - Keith Code
https://youtu.be/pN91HM16TFY
Yep. Cheesy acting but well worth watching. And then re-watching every so often.
And of course practice proper techniques taught while out riding.

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Old 09-07-2019, 04:19 PM
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I have seen exactly that sort of crash far more times than I can count.
From the beginning where they are in the entrance to the corner his body position is completely wrong. Too many MotoGp videos promulgating a typical rookie mistake. Despite that he's doing pretty well and has gobs of clearance in reserve. Then comes the curveball (couldn't resist): the radius slightly tightens up after the driveway / intersection and his original track puts him wide. Since he is looking not too far past his front tire he misses the change, and doesn't have the time or know how to tighten the arc he is following as his attention is fixed on the edge of the road and the badness past it, and he goes into "OH SHIT!!!" mode, also known as rider's cognitive shutdown. We saw the result. At least he did survive albeit with multiple serious injuries, and gave up motorcycles.

For an experienced rider this is so easy to deal with she / he probably wouldn't notice it at all.
Know I wouldn't.

Just looking as far down the road as possible would have resulted in a boring video. At least for that corner. A few turns later however...

Rob

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On the other hand, if it has not been done never assume it is impossible to do it.
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Old 09-07-2019, 07:12 PM
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I will add this, I've watched quite a few motorcycle crash YouTube compilations. A lot of those accidents happen when the guy who crashed, is riding with another guy(s). I've had at least 7 guys run off the road while trying to run with me. Beforehand everybody agrees that "we're going to take it easy today". Then the engines start, and common sense goes out the window. Im as guilty as anyone. I ride alone now. Have for years.

Another thing I've noticed is guys falling off motards left and right. It's a dirtbike. Putting street bike tire on it does not make it a streetbike.

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Old 09-07-2019, 08:44 PM Thread Starter
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Originally Posted by Sniper-x View Post
I will add this, I've watched quite a few motorcycle crash YouTube compilations. A lot of those accidents happen when the guy who crashed, is riding with another guy(s). I've had at least 7 guys run off the road while trying to run with me. Beforehand everybody agrees that "we're going to take it easy today". Then the engines start, and common sense goes out the window. Im as guilty as anyone. I ride alone now. Have for years.

Another thing I've noticed is guys falling off motards left and right. It's a dirtbike. Putting street bike tire on it does not make it a streetbike.
I've never seen the logic of a group ride. Everyone is at their own level, why in the world would anyone want to mix all those ridding skill levels together? There's zero benefit, maybe meeting up somewhere to have a meal, IDK.

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Old 09-07-2019, 09:06 PM
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I know exactly what what you mean about group rides with vastly different skill levels or how fast everyone wants to go. I find myself making better friends with people the quicker they are, as people of much higher skill typically have a much greater love for motorcycles and for that reason, we get along better. When you ride with people who want to and can go just as fast and as safely as you want to, a group ride can be a great experience. Seeing a snake of bikes ripping through corners is quite the sight. I like to be able ride with people that I trust will not exceed their boundaries. People going slow is not the problem, we can always wait. People riding dangerously and or crashing is what annoys me.

There's few things I hate more than having to lead a group ride because nobody knows where to go or how fast to go, and places I'd normally speed up to hit good turns, I have to slow down knowing the idiot behind doesn't know the road and will crash himself out unless I pace him through. I relish the group rides where we can share awesome motorcycle experiences, bike swap, ect, and hate the ones that have me pushing some poor guys bike out of a ditch. Big groups are great for banter when off the bikes, but small groups are best for actually riding.

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Old 09-07-2019, 09:24 PM
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Here is an excellent video of how and why counter steering works. I watch this every so often, it's still entertaining and fascinating.


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Old 09-08-2019, 05:41 AM
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I’d say the biggest factor for a successful group ride, especially of varying skill levels, is maturity.

I know it is cliche to say ride your own ride. But if you are with mature riders, it can/will happen. When you are with a group that everyone wants to prove they are “fast,” when maybe they aren’t, is when you get in trouble.

Maturity in the leader is also key. He has to be willing to wait at turns/stop signs to let the slower riders catch up and stay a part of the group. So that they are actually comfortable riding their ride and don’t feel that they will be left behind and get lost.

I ride with a Meetup group that runs just like this. The organizer is a great guy (who is fast) but is dead serious about every one riding to their ability but he will wait at stops/turns to ensure the slower riders stay with the group. He also has been riding the local roads for years and knows great routes.

Rides usually have around 5 people show up. But he will cap it at 10.
The last ride I was on was big with 10 people. It naturally separated into two sub-groups. One at a very fast pace and one at a good pace but not as fast.
I started out in the middle of the pack, but had 2 riders let me pass when they saw I wanted to run with the lead group.
That ride also had 2 female riders, one in the lead group. That is a big sign of maturity in the riders that did not have the skill to keep up and did not try to, as in an immature group many would have even more desire to “prove” themselves since there were females present.

There have been times when a new to the group rider was slow. He was allowed to ride his ride and caught up at the turns/stops.

I really enjoy the rides also because it allows me to go faster on roads I don’t know, then I would by myself. I know I can safely keep up with Keith and the fast guys, so since he is leading and knows the roads very well on his planned route I can keep pace with him through the tight stuff. Where if I was by myself on an unknown road would need to keep the pace a bit slower.

And then when the ride is done, you have a great group of folks to enjoy a meal with.

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Old 09-08-2019, 01:06 PM Thread Starter
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I guess I just don't get the purpose of a group ride. I get that people that have a similar interest like to be together, but riding a motorcycle as a group just doesn't seem to have any benefit vs just riding alone. I can see that once you get somewhere, you can hang out and check out the rides, but other than that, the actual riding part doesn't have any appeal to me.

I know I'd always be concerned about being too close or too far, just don't see the appeal.

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Old 09-08-2019, 01:59 PM
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Quote:
Originally Posted by Pvster View Post
Here is an excellent video of how and why counter steering works. I watch this every so often, it's still entertaining and fascinating.
A neat video, and the math is easily understood, but it has little to do with how countersteering works. If precession was the driving force in initiating a lean the effort required would decrease as speed (angular momentum) increases. It does not. In fact the effort increases exponentially with increase in angular momentum. Why? According to the gyroscope right hand rule when a rotation (torque) is applied the resultant is a force at a right angle to the plane of the axle. In other words it is trying to move (for example) the right fork leg upward while trying to move the left fork leg downward. Since the forks cannot move independently of each other the precession is constrained, resulting in increased effort at the handlebars as speed increases. Neatly explains why MotoGP riders come off the track with blistered hands from forcing the wheel in a direction it does not want to go. If not precession, how does countersteering work?

Outtracking

The physics of it is pretty simple.
(Illustration 1) When traveling in a straight line a motorcycle is quasi stable, considering that at rest its natural state is laying on its side, and will continue straight until it becomes necessary to initiate a turn.
(Illustration 2) When starting (for example) a left turn the bars are turned to the right. This results in the front end of the bike moving to the right of its original path. Remembering Newton’s first law of motion: “A body in motion tends to stay in motion until an external force is applied”, the mass of rest of the bike and the rider wants to continue to go straight but with the front going to the right the mass pivots on the combined CG of bike and rider to the left, leaning to the left.
(Illustration 3) As long as the torque is applied to the handlebars the lean angle will continue to increase until either the rider moves the front wheel to track into the turn, or until the bike finds a stable condition by laying on its side on the road, followed by an insurance claim.
(Illustration 4) Once in the turn and the torque is released the wheel will of its own accord track into the turn, abetted by small countersteering inputs from the rider. In this condition it is stable in the turn and the rider can let go of the bars (NOT RECOMMENDED!) and as long as the throttle and the rider’s body position does not change it will continue in the turn. Steering out of the turn is accomplished by applying torque in the opposite direction to lean up to vertical.
That’s right … leaning is just a controlled fall!

Rob
https://en.wikipedia.org/wiki/Countersteering
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Old 09-09-2019, 12:20 AM
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Originally Posted by robtharalson View Post

The physics of it is pretty simple Ö leaning is just a controlled fall!

https://en.wikipedia.org/wiki/Countersteering
This stuff I get - the precession stuff, hmmm...

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Old 09-09-2019, 08:20 AM
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This stuff I get - the precession stuff, hmmm...
Conceptualized, it's much easier to get a handle on.
The short story is this, by turning the handlebars at a faster rate of degrees per unit time, one increases the "roll moment" = bike leans at a faster rate in terms of degrees per unit time.
The roll moment in simplistic terms can be viewed to be like a leverage effect you can access.
So, the harder you force upon the bars while countersteering, the more roll moment you get, which increases the leverage effect you get towards getting the bike to roll over off its vertical axis.
Keep in mind there is a distinct difference between the rate of bar rotation and the degrees of bar rotation.
A faster "rate" gives you a faster "leaning over" rate.
More "degrees" gives you a tighter radius of turn.
The two can be combined depending upon the need.

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Old 09-09-2019, 11:39 AM
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Originally Posted by nathanktm View Post
My friend is the one who recorded this video. He wound up breaking some ribs, his hip and his collar bone. The rider who crashed sold all of his gear last week and has given up riding. =(

From my measurements, the 919 grounds out at roughly 50 degrees of lean in stock form with the hero blobs removed. It's significantly less than what the average track bike achieves. How exactly did you set up the 919 to be "tall?" Or rather, what are some go-to mods for better track performance? To be honest, I don't believe my honda with stock suspension and 60k miles could even handle the increased energy from higher lean angles. It already feels like it's being twisted into knots if I'm not ultra smooth. God forbid I hit a dip mid corner, the rear shock pumps a good 3-4 times before it settles out, and thats with the rebound full hard. My guess is a cartridge kit, a good rear shock and a good set of rearsets + trackday rubber would greatly benefit the bike. Then again, for the same price you can just buy a track-ready sportbike which will easily outperform what I just suggested.
#1 by far is hearing about the injuries, but hopefully that hip mends nicely, and my guess is that it's been fastened together.

#2 is a reply to your other points, trying to keep it short and sweet.
919 re 50 degrees of lean
I donít know how you derived that number, by static measurements (a flawed approach as doesnít included suspension loading from the turn), or other means, perhaps off of a fixed mount camera?
Anyway, somewhere in the low 50s is what Iíd guess at for a riding limit.
As in being on an UJM with tires more capable than the bike with mere mortals riding it.
Iíll bet most Group 2 track day bikes never see 55 degrees.
Just look at the respective tire contact areas and their levels of wear for comparison.
Personally, I try to use as few degrees of lean as I can for any given speed and radius of a turn.
Ultimately, a 919 is no super sport and canít be made into one.
But a well set up and well ridden 919 is no slouch in the right hands.
Keep in mind also that when you get into the 50s, your overall ďsuspensionĒ becomes very reliant upon the tire, so if you donít have a tire designed for such a lean angle, and donít pressure it properly, you wonít get the required tire suspension effect to compensate for the loss of suspension effect at the forks and rear end because of the high angle of lean.

Re a Tall Set Up
It means the chassis ride height has been increased (to elevate the C of G) while still using a good spring rate with a good amount of installed preload, and maintaining good front end geometry.
In the case of a 919, it also alters the unlinked swingarmís angle enough that the net squat is reduced.
I use an adjustable length rear shock to deal with the rear end.
Iíve been forced to wind in the ride height adjusters all the way, and there is a sacrifice of compliance near full fork extension doing this.
Iíve also dropped the tubes a bit in the clamps a bit to get the front end where I want it.
This winter I will fit a set of custom made extended fork caps that I already have, and then not need more than a ring of front end ride height tinkering range, by playing with tube drop in the clamps.

Re Stock 919 Suspension
What you describe is less than no surprise.
The front is better than the rear.
2004+ are worse than earlier, because of the mush rear spring rate.
They are also squat meisters.
If you can find LDHís writeup of years ago that was on 919.org, see how even with the stiff rear spring of his 2002 still resulted in serious swing arm yo yoing at pace under certain condition.
The rear rebound adjuster on the 2004+ is pretty much for looks in my mindÖÖÖÖÖ..

Re Upgrading 919 Suspension
Front end: proper springing, valving, low speed compression bleed porting, shimming, oil level, and installed preload.
Rear end: Adjustable length 3 way adjustable shock with digressive compression piston facing, properly sprung, properly setup re soft top out if said shock has no internal soft top out.
Rear sets: optional, but a good idea as no levers will grind and more importantly, no extreme foot repositioning will be necessary to keep oneís inside foot from getting crushed by the folding stock peg.
Tires: dedicated track day tires are a mistake on a street use bike also being tracked, race tires even more so. Further, using Dunlop as an example, what really is the best choice? Q3+ or Q4? If said tire is to see cold wet early and late season use, Iíd go Q3+ and give up the track only displayed superiority of the Q4.

Re Track Ready Sport Bike
A dedicated track day super sport bike is fantastic.
(Especially a good well built, well set up, and well maintained retired race bike.)
But if one canít have one, and has an UJM they love and want to keep for Universal use, then there is less than nothing wrong for using a 919 at track days, be it stock or upgraded.
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Old 09-09-2019, 01:36 PM
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I like the simplicity of this: in order to turn left, I pull back on the rh bar, to steer my wheels out from underneath my CoG, and initiate the "fall". I continue to "fall" leftwards until I pull back on the lh bar, to steer my wheels back under my CoG, and put myself upright again.
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Old 09-09-2019, 01:45 PM
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Quote:
Originally Posted by K1w1Boy View Post
I like the simplicity of this: in order to turn left, I pull back on the rh bar, to steer my wheels out from underneath my CoG, and initiate the "fall". I continue to "fall" leftwards until I pull back on the lh bar, to steer my wheels back under my CoG, and put myself upright again.
Just a slight tweak to yours, in an effort to cover just a bit more:

I like the simplicity of this: in order to turn left, I pull back on the rh bar, to steer my wheels out from underneath my CoG, and initiate the "fall". I continue to "fall" leftwards until I pull back on the lh bar , to steer my wheels back under my CoG, and put myself upright again TO RETURN TO STRAIGHT LINE TRACKING ,UNLESS I HAVE INSTEAD REACHED THE SPEED X RADIUS EQUILIBRIUM I WANT FOR THE LEFT HAND TURN I AM MAKING (IN WHICH CASE I WOULD NOT WANT TO MAKE THE BIKE AND I UPRIGHT AGAIN).
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Old 09-10-2019, 03:01 AM
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Quote:
Originally Posted by mcromo44 View Post
Just a slight tweak to yours, in an effort to cover just a bit more:
Tweak upon tweak:

In order to turn left, I pull back on the rh bar, to steer my wheels out from underneath my CoG, and initiate the "fall". I continue to "fall" leftwards until I pull back on the lh bar , to steer my wheels back under my CoG, and put myself upright again to return to straight line tracking, unless I have instead reached the speed x radius equilibrium I want for the left hand turn I am making (in which case I would not want to make the bike and ME upright again YET).
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Old 09-10-2019, 07:56 AM
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Quote:
Originally Posted by K1w1Boy View Post
Tweak upon tweak:

In order to turn left, I pull back on the rh bar, to steer my wheels out from underneath my CoG, and initiate the "fall". I continue to "fall" leftwards until I pull back on the lh bar , to steer my wheels back under my CoG, and put myself upright again to return to straight line tracking, unless I have instead reached the speed x radius equilibrium I want for the left hand turn I am making (in which case I would not want to make the bike and ME upright again YET).
I dare not tweak the tweak!
The YET is a nice addition.
Nice grammatical correction by the ME.
(Grammar is not at all a strength of mine.)
Upon seeing your fix, I quickly fished about on the web re the use of ME versus I.
I was pondering the singular rule, while contemplating whether the bike and rider should be seen as a dynamic singular entity in terms of the over all physics, seeing it's really about the physics.
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Old 09-10-2019, 04:19 PM
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Great paper on countersteering, the role gyroscopic precession plays (very little) including a sidebar on the NHSA rear steering motorcycle which nobody has been able to ride for more than 2.5 seconds. Our taxes at ... work?
https://lup.lub.lu.se/search/ws/file...388/625565.pdf
Math is a bit more complex, but not really needed until you want to build your own bike/motorcycle. Page 38+ for precession cancellation.

Rob
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If it has already been done, it is safe to assume it is possible to do it.
On the other hand, if it has not been done never assume it is impossible to do it.
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Old 09-11-2019, 12:32 AM
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Quote:
Originally Posted by robtharalson View Post
Great paper on countersteering, the role gyroscopic precession plays (very little) including a sidebar on the NHSA rear steering motorcycle which nobody has been able to ride for more than 2.5 seconds. Our taxes at ... work?

https://lup.lub.lu.se/search/ws/file...388/625565.pdf

Math is a bit more complex, but not really needed until you want to build your own bike/motorcycle. Page 38+ for precession cancellation.



Rob
Ok, THIS is cool! Thanks for sharing along with your other post. The physics behind all of this is fascinating.

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Old 09-12-2019, 08:28 PM
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Pretty interesting physics here.. the bike does a fairly clean front flip, vertically, after impact.

https://www.independent.co.uk/news/u...-a9102821.html

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Old 09-13-2019, 11:07 AM
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Ah, the perfect example of the physics of drunken stupidity.

Rob
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