You might want to watch this, but you've been warned...

That snap shot was late in the game, the rider had already tried several times, with no success to "steer" the bike away from the truck. He's doing it AGAIN in the pic. Had he really understood his bike he would have been well clear of the truck's path at this point. My reason of showing that pic was to point out that the bars are still being pointed the wrong way. I am not flogging this poor SOB for his sins. I'm saying, If you practice, if you make it "instinctive", counter steering may very well save your bacon some day. You will find more enjoyment riding as your turns become graceful and flowing not a series of choppy corrections. If you don't understand counter steering even if your turns LOOK smooth you will always be feeling you are "cornering as fast as possible". When you use counter steering you will know how to effortlessly tighten your line, your confidence, control, ability to avoid obstacles, will all go up.
 
TwoManyXS1Bs said...... "In summary, my feeling is that, for this particular snapshot, an impact is inevitable."

That was what I said, back in post #9, about a week ago. For this particular rider, once he chose the wrong line, and was going too fast for his experience, the crash was inevitable.

You can all second guess, if a more experienced rider could have missed hiting the truck, but guess what....................a more experienced rider would not have put themselves in that dangerous position.

That's what defensive driving is all about (cars or bikes). Don't put yourself in situations where some amazing driving skill will save the day for you. I don't have amazing driving skills or super fast reaction timing, so I use defensive driving in my car and my bike.
 
TwoManyXS1Bs said:
Well, THAT's interesting.

40 years ago, a statistical analysis was done down here that found that the accident rate was much lower for helmetless riders, than for riders wearing helmets. They reasoned it was because of the "protected womb" effect. Riders with helmets would do things that the others wouldn't.

Maybe our ol' XS650s are safer because we can't push them like modern sportbikes...
Click to expand...

Maybe because the helmetless riders have a higher death rate and a lower accident rate...you know, because most accidents become fatalities with no helmet.
 
Forget the truck. If the rider had countersteered to maintain his lane before the truck came into view, the accident wouldn't have happened. Blowing a turn is blowing a turn. It's obviously worse when you drive head on into a truck.
 
I can't help but think of all those horrible accidents, where the drunk is the only survivor.

I had a pretty serious fall down a flight of steps while I was grogged-up on Chemo and pain meds.
Basically fell, bounced and flopped about like a wet rag.

Nothing happened, no bumps, bruises, or broken bones.

Wierd...
 
jetmechmarty said:
Forget the truck. If the rider had countersteered to maintain his lane before the truck came into view, the accident wouldn't have happened. Blowing a turn is blowing a turn. It's obviously worse when you drive head on into a truck.
Click to expand...

I agree completely Marty. The rider did not have enough experience, to know how important it is to chose the correct line entering a blind turn (or any turn). Excessive speed was also working against his ability to steer (call it countersteer if you wish to) .
 
Crikey.

My son wants me to teach him to ride. This will make an excellent lesson for two points: One, countersteering IS HOW you turn. Two, Total situational awareness. If you can't see it, ALWAYS ride like a fire engine or a ravine is around the next corner...or cross street...or in your blindspot.

Man, this video just makes me go ouch. I'm glad the guy lived, because we're not usually that lucky.
 
hard_y_rd said:
There is no way that anyone's brain in a panic situation like that would want to turn the bars left into oncoming traffic within the seconds that it happened. I'm surprised he didn't lock her up.
Click to expand...
I am by no means bashing you hard_y_rd, but, that sounds like inexperience talking there. The following response is aimed to everybody. Panic situation or not, counter steering is the ONLY way a bike will steer. It's not a choice, people. You can't turn it on and off. It's physics and it applies ALWAYS, period! Only at, what I will call, parking lot speeds, only a few MPH, will you turn the handlebars conventionally to turn the motorcycle. Again, I state, counter steering is not a choice, it SHOULD be an instinctual behavior and if you, as a rider, can't wrap your head around the handling characteristics of a 2 wheeled vehicle or if you have to think about steering every time you navigate a corner, then you, frankly, are a hazard to yourself and everybody else and do not belong on a motorcycle. I know I sound harsh but I'm just being frank. :thumbsup:
 
You go scooter magoo! I think if you just rode bikes it would be easy but here in the great white north I have to retrain on counter steering each spring and do regular refresh sessions during the season.
 
TwoManyXS1Bs said:
This is a good physics exercise.
Let's look again at gggGary's snapshot of the bike's and truck's situation just moments before impact.
29F7D41C00000578-3139121-image-a-32_1435248624845.jpg


Now, establish some data factoids.
(Sorry metric guys, you'll have to fend for yourselves)

1 G = 32 feet per second per second = Acceleration due to gravity
1 mph = 1.467 feet per second

Now comes the fuzzy analysis.
Best guess estimates from examining the video (numbingly over and over and over):
The motorcycle speed, approaching impact = 44 mph (65 fps)
Viewing the video, with stopwatch, trying to account for the slight fisheye imaging, was able to guesstimate the 65 foot travel over one second.
This gave the estimate of the distance to impact = 40 feet
Which means a time to impact = 0.6 seconds

The motorcycle is continuing its turn, after exiting the curve, and appears to have a lean angle of 20°.
The tangent of 20° = 0.36
Which gives the centripetal acceleration from that existing lean angle = 0.36 G

This pic shows the current path to impact in red.
I'd like to be at least 4 feet to the right of that, to clear handlebars and such from the truck.
To do that, means following the track in green.

View attachment 57480


So, let's calculate the amount of acceleration to get that additional distance to clear truck = 4 feet
where: s = distance, a = acceleration, t = time
s = 1/2 a * t * t <--(standard formula when acceleration is constant)
a = 2s / (t*t) <--(transformed to solve for 'a')
a = 2 * 4ft / (0.6sec * 0.6sec) <--(plug in our values)
8 / 0.36 = 22.2 fps/s = 0.69 G <--(simplify and solve)

Acceleration needed to travel 4 feet in 0.6 seconds = 0.69 G

With the bike's existing centripetal acceleration at 0.36G, then adding the additional acceleration of 0.69G, we get:
Total acceleration needed = 0.36G + 0.69G = 1.05G

However, the typical G limits for street compound tires = 0.85G
Which means that there's not enough traction to achieve the escape route.

It gets worse if you account for the time losses due to:
- Application of corrective countersteer
- Time required for the motorcycle to achieve the new lean angle

In summary, my feeling is that, for this particular snapshot, an impact is inevitable.

Which explains why I grit my teeth everytime I see that pic...
Click to expand...


I think you are wrong here 2M, there is still plenty of room to miss the truck IF he would turn the bars correctly TO THE LEFT.

CounterSteer04.jpg


CounterSteer04.jpg
 
I really never understood why "countersteering" (I don't like that term much) is considered counterintuitive. What it really amounts to is being aware of steering inputs at the hands rather than the shoulders. Try thinking of it this way: Push down, heel down. Sure, a downward push on the bars will turn the wheel away from the path of travel; ignore that as coincidental.

It's my guess (and that's all it is, folks, not an argument) that a lot of the trouble that we attribute to lack of steering skills is actually caused by target fixing: a driver or rider will tend to steer where he's looking, and if you look at the object you're trying to avoid, you're very likely to run right into it. Instead, look into the path you need to follow to get out of trouble. One cure for target fixing is to keep your eyes moving.
 
gggGary said:
I think you are wrong here 2M, there is still plenty of room to miss the truck IF he would turn the bars correctly TO THE LEFT...
Click to expand...

Could be. I spent a lot of time trying to ascertain the various positions, speeds, times, and (the most difficult) the bike's frame angle (ground track). The images have some optical illusions, parallax, fisheye challenges. Then I went crosseyed, slide rule got fuzzy, chalkboard got dirty.

But, it was a fun analysis...
 
Re-ran the calculations using my older tool, the "Pucker Factor Figurator".
It keeps redlining into "Holy crap! --- Brace for impact!".

An imprecise and difficult tool, since the pucker measurement is easily obscured by the size of the balls.

And must be carefully calibrated. Mine's set on:

Rider type: Old man
Reflexes : None
Reaction time: Act of Congress
Attention span: Goldfish
 
TwoManyXS1Bs said:
pucker measurement set on:

Rider type: Old man
Reflexes : None
Reaction time: Act of Congress
Attention span: Goldfish
Click to expand...


That's two of us, I like the above comment about a parking lot with cones and an instructor choosing which way you have to turn. That'll get you thinking. Very easy to set up and a fun group activity at any gathering!
 
TwoManyXS1Bs said:
Re-ran the calculations using my older tool, the "Pucker Factor Figurator".
It keeps redlining into "Holy crap! --- Brace for impact!".

An imprecise and difficult tool, since the pucker measurement is easily obscured by the size of the balls.

And must be carefully calibrated. Mine's set on:

Rider type: Old man
Reflexes : None
Reaction time: Act of Congress
Attention span: Goldfish
Click to expand...
Thank you for an explanation I can understand! Now I get it.
 

Similar threads

willis
Big Bore Kit (BBK) tuning thread
Replies
10
Views
806
5twins
5twins
R
1977 XS650
2 3 4
Replies
60
Views
1K
5twins
5twins
Mannyroad
URGENT HELP to source electric ignition for rephased motor
Replies
10
Views
495
Mannyroad
Mannyroad
Jim
Side Stand Blues
Replies
11
Views
608
JOHNDADDY
JOHNDADDY
STARCROSSEDMOTO
77-81 XS650 "JADE" Tribute Build
2
Replies
32
Views
2K
JOHNDADDY
JOHNDADDY
Back
Top