Traction

[Frank Krygowski]

We got 12" of wet, dense snow today, but the plows came out, and the
roads aren't terrible, despite a bit of slush and some snowy patches. So
this evening, when I had to pick up a prescription at the local
pharmacy, I flicked on the dynohub headlight & taillight and rode to the
pharmacy and back. As I did so, I noticed a reflex retained from my
teenage years of winter newspaper delivery by bicycle.

When I'm making a turn on a surface that is, or might be, very slippery,
of course I slow down. But I also reflexively make an effort to keep
the bike vertical. To balance, I lean my body inward from the bike.

Obviously, the center of gravity of my body+bike must be a bit inward
(i.e. toward the center of the curve) for balance and stability. The
amount the c.g. is inward is a simple function of speed and radius of
turn. But in dry conditions, I achieve this by tilting the bike while
keeping my body in the normal position relative to the bike. In
slippery conditions, I do it instead by leaning my body away from the bike.

Do others do this? If so, why?

To achieve a certain lateral acceleration (or sharpness of turn), the
amount of lateral friction force (or traction) is fixed. And I don't
think there's any great difference in friction coefficient for my
Paselas when they're vertical vs. tilted, so the likelihood of a skid
shouldn't be much different. Psychologically, it _feels_ like some sort
of secondary effect - as if I have a better chance of stopping the
slide, or catching the bike, or just not falling, if the bike is vertical.

Maybe this is a valuable reflex I picked up by trial and error in my
paperboy days. Or maybe it's some unconscious superstition. At my age,
I'm a bit afraid to do an A-B test to see.

So: Comments?


--
- Frank Krygowski

[deacon mark]

I did it on the ice 10 weeks ago and broke my hip if you remember so be
careful. I am happy to report I am back to riding outside if I want when the
weather gets better but even to my surprise I started back running a week
ago easy. Have run 5.5 miles past two days on the treadmill.

But if I were you given my experience with ice just stay on the trainer.


Deacon mark cleary

"Frank Krygowski" wrote in message news:na0f1h$83m$1...@dont-email.me...

[avag...@gmail.com]

you taught engineering n have a degree ?

[John B.]

I think that turning while keeping the bike vertical, i.e., by simply
turning the handle bars, is probably how most kids who are first
learning to ride turn and usually they fall over a few times before
they learn to lean the bike.

But, on the other hand if either the front or rear wheel skid one
automatically, it seems, compensate by trying to move the CG toward
the outside of the turn, in the direction of the skid. If on foot
slips and slides happen very quickly and it is hard to remember what
one did but if skating one tends to do the same thing throw one's
weight in the direction of the skid to try and stay vertical.
--
cheers,

John B.

[Tosspot]

On 17/02/16 01:34, Frank Krygowski wrote:
> We got 12" of wet, dense snow today, but the plows came out, and the
> roads aren't terrible, despite a bit of slush and some snowy patches. So
> this evening, when I had to pick up a prescription at the local
> pharmacy, I flicked on the dynohub headlight & taillight and rode to the
> pharmacy and back. As I did so, I noticed a reflex retained from my
> teenage years of winter newspaper delivery by bicycle.
>
> When I'm making a turn on a surface that is, or might be, very slippery,
> of course I slow down. But I also reflexively make an effort to keep
> the bike vertical. To balance, I lean my body inward from the bike.
>
> Obviously, the center of gravity of my body+bike must be a bit inward
> (i.e. toward the center of the curve) for balance and stability. The
> amount the c.g. is inward is a simple function of speed and radius of
> turn. But in dry conditions, I achieve this by tilting the bike while
> keeping my body in the normal position relative to the bike. In
> slippery conditions, I do it instead by leaning my body away from the bike.
>
> Do others do this? If so, why?

Yep. Makes me feel like a Motorcycle Grand Prix racer.

> To achieve a certain lateral acceleration (or sharpness of turn), the
> amount of lateral friction force (or traction) is fixed. And I don't
> think there's any great difference in friction coefficient for my
> Paselas when they're vertical vs. tilted, so the likelihood of a skid
> shouldn't be much different. Psychologically, it _feels_ like some sort
> of secondary effect - as if I have a better chance of stopping the
> slide, or catching the bike, or just not falling, if the bike is vertical.

I *think* it gives a small margin. With the normal turn the CoG, point
of lateral resistance (CoLR) are in a plane, if the CoLR moves outwards,
out of plane, the CoG is now helping it move further out of plane. If
you hang off, you get a few inches while the *opposite* is happening.

Just my tuppence worth.

[Andre Jute]

Jobst Brandt addressed the question of bicycle/rider angle and traction in one of his short FAQ pieces. Try Google. I'm not so sure there's anything to add to what he wrote.

Andre Jute
Now let us praise famous men -- Ecclesiastes

[avag...@gmail.com]

COUNTERSTEERING, AND LEANING WEIGHT FORWARD FOR FRONT WHEEL TRACTION REDUCES FRONT WHEEL TURNING FOR ALL TURNS IN THAT FRONT WHEEL DOESN'T TURN AS MUCH.
TURNING A WHEEL FROM THE PREVIOUS PATH REDUCES GRIP: NEWTON

AND NOT COUNTERSTEERING REDUCES CONTACT SURFACE.


NOT COUNTERSTEERING REDUCES SECONDARY MOTIONS POTENTIALS INSIDE THE NOW TURNING WHEEL...ALL ADDITIVE FROM YAW FORCES OUTSIDE THE PREVIOUS PATH. INCREASING DISTORTION OF CONTACT PATCH.

[AMuzi]

Yes, I've noticed that; one intuitively tends to keep the
bike more vertical where there are traction losses like
ice/snow. Maybe for faster correction to front slip?

--
Andrew Muzi
<www.yellowjersey.org/>
Open every day since 1 April, 1971

[sms]

Obviously he needs a two wheel drive or AWD bicycle for these conditions.

[Doc O'Leary]

For your reference, records indicate that

Frank Krygowski <frkr...@sbcglobal.net> wrote:

> Do others do this? If so, why?

I like to keep my body weight as dynamic as possible when riding over
questionable surfaces. When riding in snow, even along a straight line,
my experience tells me that I’m going to be better able to man-handle
the machine to keep it upright if I don’t have all my weight dead on the
seat.

> Psychologically, it _feels_ like some sort
> of secondary effect - as if I have a better chance of stopping the
> slide, or catching the bike, or just not falling, if the bike is vertical.

This may be part of the reason I do it, too, but it may also have a physical basis. A bike that is farther from vertical seems like it will not *regain* traction as easily as one that is near vertical. And if a point of contact
starts to slide, I don’t expect recovery is going to be very possible if I
am stuck with the tilt+gravity adding energy to the problem.

--
"Also . . . I can kill you with my brain."
River Tam, Trash, Firefly

[avag...@gmail.com]

LIMITS are HIGHLY

SUBJECTIVE.

I am a ground sloth. But I can do the Peterson in muh van ....

come up alongside in rainstorm on the outside of the Interstate next to a white knuckler going the speed limit...

and wiggle the truck back n forth then make it dance up and down..

jus saying uknow ......

[avag...@gmail.com]

<<<<<<<<<<<</////////////////////////////////////+

no. is a lot faster prob 10% right off.....


last I looked aloooooong time ago....20 years ? there was some disorientation in here prob reflective of this thread

this is how one rides a bike. Was either Brandt or Brown discoursed in learning cycling early in the brain formative connection development phase so countersteering would be go kart natural in opposite of that.


https://www.google.com/#q=bicycle%20countersteering%20site%3Ayoutube.com

I have instructed older folk who on trying CS fell onto the parking lot

https://www.google.com/#q=bicycle%20countersteering%20site%3Ayoutube.com

[avag...@gmail.com]

)))))))))))))))))))))))\XX

off course what wud a handling thread be without

https://www.google.com/#q=isle+of+man+sidecar+accidents

[avag...@gmail.com]

https://www.google.com/#q=isle+of+man+sidecar+accidents&tbm=vid



~

[avag...@gmail.com]

waste time on this one ....3 minutes in....


your ad is not my ad hehehhehheheh .....



https://www.youtube.com/watch?v=UqUa0dduw9o

[Frank Krygowski]

You're having quite a conversation with yourself!


--
- Frank Krygowski

[avag...@gmail.com]

FranKly. I'll look for The Confrontation after dinner. Went thru that one via th Brit tabloids n club news. Max Duel. Poss newbies would enjoy that one.

Sic Gloria Transit

with bicycles tho limits are easier reached. certainly less costly easier exceeded n recovered from.

My knowledge in the area is very limited as no group rides no peloton np race attendance. I see only sporadic hobby riders who do not AFAIK countersteer.

[avag...@gmail.com]

cannah find the braking area stand off at that same coroner

but here

https://www.youtube.coms/watch?v=zyi_Eu6mxyo

https://www.youtube.com/watch?v=-v7pxwdqGQM

https://www.youtube.com/watch?v=7x0CBWlg2b4

https://www.youtube.com/watch?v=uHidS8AjMS0

https://www.youtube.com/watch?v=8d3r2LNNiUA

[Joerg]

On 2016-02-16 16:34, Frank Krygowski wrote:
> We got 12" of wet, dense snow today, but the plows came out, and the
> roads aren't terrible, despite a bit of slush and some snowy patches. So
> this evening, when I had to pick up a prescription at the local
> pharmacy, I flicked on the dynohub headlight & taillight and rode to the
> pharmacy and back. As I did so, I noticed a reflex retained from my
> teenage years of winter newspaper delivery by bicycle.
>
> When I'm making a turn on a surface that is, or might be, very slippery,
> of course I slow down. But I also reflexively make an effort to keep
> the bike vertical. To balance, I lean my body inward from the bike.
>
> Obviously, the center of gravity of my body+bike must be a bit inward
> (i.e. toward the center of the curve) for balance and stability. The
> amount the c.g. is inward is a simple function of speed and radius of
> turn. But in dry conditions, I achieve this by tilting the bike while
> keeping my body in the normal position relative to the bike. In
> slippery conditions, I do it instead by leaning my body away from the bike.
>
> Do others do this? If so, why?
>
> To achieve a certain lateral acceleration (or sharpness of turn), the
> amount of lateral friction force (or traction) is fixed. And I don't
> think there's any great difference in friction coefficient for my
> Paselas when they're vertical vs. tilted, so the likelihood of a skid
> shouldn't be much different. Psychologically, it _feels_ like some sort
> of secondary effect - as if I have a better chance of stopping the
> slide, or catching the bike, or just not falling, if the bike is vertical.
>

Usually the bike is leaned and the body counteracts the lean a bit, like
here:

https://www.youtube.com/watch?v=WkK05NXLFhk

At least that's how I learned it early on. Mostly because as a kid I
preferred riding my bicycle on motocross circuits, often in the rain
when nobody was out there. Fun! (well, my mom didn't think so when she
saw my clothes)

> Maybe this is a valuable reflex I picked up by trial and error in my
> paperboy days. Or maybe it's some unconscious superstition. At my age,
> I'm a bit afraid to do an A-B test to see.
>
> So: Comments?
>

Strange. I do it opposite and see others do it similarly: Lean the bike
and then move the upper body opposite, towards the outside of the curve.
This keeps the CG more towards the line where the wheels roll. When
riding at the limit I sometimes stop pedaling and set a foot out. Many
MTB riders do this kind of instinctively. There are days in winter when
the bike slides sideways even on a dirt trail that looks straight
because it's all rutted and muddy. Becomes a normal riding mode quickly.

End of December when riding fat bikes on an icy road keeping the CG
almost above where the wheels touch was even more important. Move it
just an inch too far ... swish ... ka-crash.

--
Regards, Joerg

http://www.analogconsultants.com/

[avag...@gmail.com]

Joerg

try reading on this...Bicycle Science...and online.

The bicycle configuration turns right when the butt and legs/torso turn left on the saddle. The front wheel need not turn...this is the important part....the wheel need not run.

The frame turns as it fall right.

so there's no scrub or less scrub on the road from a turning motion on a straight ahead route. Less energy loss.

The motions are continuous. So at the top, the balancing rider losses less energy per 100 miles than the lesser balanced rider.

big difference. a constant energy advantage as the frame traveles in a straight line not scrubbing off energy forcing the frame into a turn.

[avag...@gmail.com]

Joerg

your youngster description seems more dirt tracking than counter steering.

opposite lock.

[Frank Krygowski]

That's really not a very comparable situation. Those guys are putting
their feet down toward the inside of the curve and using them as a
sliding support. They are not balancing as a bicyclist does.

>
> At least that's how I learned it early on. Mostly because as a kid I
> preferred riding my bicycle on motocross circuits, often in the rain
> when nobody was out there. Fun! (well, my mom didn't think so when she
> saw my clothes)
>
>
>> Maybe this is a valuable reflex I picked up by trial and error in my
>> paperboy days. Or maybe it's some unconscious superstition. At my age,
>> I'm a bit afraid to do an A-B test to see.
>>
>> So: Comments?
>>
>
> Strange. I do it opposite and see others do it similarly: Lean the bike
> and then move the upper body opposite, towards the outside of the curve.
> This keeps the CG more towards the line where the wheels roll.

If a person is actually balancing a bike around a curve, the CG can be
only in one angular location relative to the line between the two tires
contact patches. This sketch shows that angle:
https://qph.is.quoracdn.net/main-qimg-393c57cfc83eb93f8dfcc360df04ec27?convert_to_webp=true

Any body contortion - either my leaning my body more inward while
keeping the bike more vertical, or your opposite strategy - cannot
affect the orientation of the CG. It can't change the balance point.

That's why I said that my instinct for keeping the bike more vertical
must be due to some secondary effect, if it has any validity at all.

I think what's needed is for someone to try going too fast around
slippery corners over and over, testing all three strategies: rider in
the plane of the bike frame (i.e. normal), rider toward the center of
the plane of the frame (my reflex), and rider toward the outside (your
reflex). Test the strategies until it's clear which one gives the best
chance of recovering without a fall.

Obviously, it has to be someone willing to fall over and over. (Where's
Dan O when we need him?)

--
- Frank Krygowski

[avag...@gmail.com]

Dan O

Frank, your language specificity tails of from the generator discussion. Not critical but clearing...

Your suggested 'balance' motion is in the direction of counter steering...moving into the area of unturned front wheel with falling frame into corner direction.
You are moving toward what you're 'calling' balance that is a counter steering attitude coherent with a bicycle physics balance ... a low vehicle ground friction area.

[Graham]

"Frank Krygowski" <frkr...@sbcglobal.net> wrote in message news:nab17b$bel$1...@dont-email.me...

OK here is just an idea for discussion. Could it be due to the fact that while the line from the contact patch to the C of G is in fact a straight line as shown in your diagram by doing what you describe you are effectively forming a partially closed hinge with the bike being one half and your body the other. If the tyres lose traction then that hinge will start to open as the bike starts to rotate below you towards the inside of the curve. The fact that this could happen before your C of G starts to accelerate downwards due to inertial effects (the bike is much lighter than you) might buy you fractions of a second sufficient for you to take action or for the tyres to have crossed the slippery patch and regained grip. Those actions might include raising your C of G or pulling up hard on the inside bar as the bike starts to rotate both of which might increase the contact pressure enough to regain traction. Here I think it needs a few sums to see if the geometry of my opening hinge anology makes either of these two effects credible.

Cheers,

Graham.

[avag...@gmail.com]

https://upload.wikimedia.org/wikipedia/commons/8/88/Galileo_facing_the_Roman_Inquisition.jpg

[Frank Krygowski]

On 2/21/2016 5:02 AM, Graham wrote:
>
> "Frank Krygowski" wrote in message news:nab17b$bel$1...@dont-email.me...

>>
>>
>> Any body contortion - either my leaning my body more inward while
>> keeping the bike more vertical, or your opposite strategy - cannot
>> affect the orientation of the CG. It can't change the balance point.
>>
>> That's why I said that my instinct for keeping the bike more vertical
>> must be due to some secondary effect, if it has any validity at all.
>
> OK here is just an idea for discussion. Could it be due to the fact that while the line from the contact patch to the C of G is in fact a straight line as shown in your diagram by doing what you describe you are effectively forming a partially closed hinge with the bike being one half and your body the other. If the tyres lose traction then that hinge will start to open as the bike starts to rotate below you towards the inside of the curve. The fact that this could happen before your C of G starts to accelerate downwards due to inertial effects (the bike is much lighter than you) might buy you fractions of a second sufficient for you to take action or for the tyres to have crossed the slippery patch and regained grip. Those actions might include raising your C of G or pulling up hard on the inside bar as the bike starts to rotate both of which might increase the contact pressure enough to regain traction. Here I think it needs a few sums to see if the geometry of my opening hinge
anology makes either of these two effects credible.

That's the sort of thing I was wondering about. At this point, I don't
have any clear grasp of the specifics, though.


--
- Frank Krygowski

[David Scheidt]

Frank Krygowski <frkr...@sbcglobal.net> wrote:

My experience from riding in muck and snow and such, is that I
generally do what Frank described (keep the bike more upright).
I can lever the bike over to the outside if I need to, and if the bike
slides it's not going to run out of tire, which can happen when
leanning it.


--
sig 85

[Joe Riel]

"Graham" <h2gt2g42-mi...@yahoo.co.uk> writes:

> OK here is just an idea for discussion. Could it be due to the fact
> that while the line from the contact patch to the C of G is in fact a
> straight line as shown in your diagram by doing what you describe you
> are effectively forming a partially closed hinge with the bike being
> one half and your body the other. If the tyres lose traction then that
> hinge will start to open as the bike starts to rotate below you
> towards the inside of the curve. The fact that this could happen
> before your C of G starts to accelerate downwards due to inertial
> effects (the bike is much lighter than you) might buy you fractions of
> a second sufficient for you to take action or for the tyres to have
> crossed the slippery patch and regained grip. Those actions might
> include raising your C of G or pulling up hard on the inside bar as
> the bike starts to rotate both of which might increase the contact
> pressure enough to regain traction. Here I think it needs a few sums
> to see if the geometry of my opening hinge anology makes either of
> these two effects credible.

Consider the suspension aspect. A softer suspension will better deal
with small bumps, etc. With the rider on the seat, and in the plane of
the bike, the effective suspension is at its stiffest. Any deviation
from this (leaning in or out, standing on the pedals) is going to
improve this. I'm not saying this is significant, but it's something
to consider.

--
Joe Riel

[Joerg]

True, but ... when you lean your body into the curve and the thing
surprisingly starts to skid setting a foot out can cause a nasty fall or
a broken ankle. Or worse, hip damage. Leaning like the dirt bikers has
you already almost vertical, much less chance for hip damage.

Also, often I already have the foot out inches above the surface, just
in case.

> That's why I said that my instinct for keeping the bike more vertical
> must be due to some secondary effect, if it has any validity at all.
>
> I think what's needed is for someone to try going too fast around
> slippery corners over and over, testing all three strategies: rider in
> the plane of the bike frame (i.e. normal), rider toward the center of
> the plane of the frame (my reflex), and rider toward the outside (your
> reflex). Test the strategies until it's clear which one gives the best
> chance of recovering without a fall.
>
> Obviously, it has to be someone willing to fall over and over. (Where's
> Dan O when we need him?)
>

:-)