Just failed the CA DMV motorcycle popsicle test (and I thought Ihad passed)

Come back, sleepy-head!

Here you've got us all sitting anxiously on the edges of
our seats, wanting to hear the carefully reasoned logic
explaining how three-wheeled tricycles and two-wheeled
bikes can steer the same way -even though that defies
physics- and now you're going to run away and leave us
all in the lurch instead of educating us?

One would think that since you've actually got a willing
audience for the first time in your life you'd be happy to
take advantage of the fact, but no.......

I wonder why that could be?

 

Dude. Just stop already. Reasoning about physical processes is not
something you do well.

Lateral loading is dominant in "high speed" turns; negligible at "low
speeds". Geometry, the relationship between the front wheel and rear
wheel tracks, dominates at "low speeds." This is clearly what was meant
by "At low speeds the bike follows the track ..."

You can shove your teaching credentials where the sun doesn't shine.
Attached to your name and posting history, they talk only to deficient
selection standards.

As though to a 4 y.o., then. Countersteer initiates a lean. Lean
pertains to lateral loading. Toppling moment, coning angle, and camber
thrust are relevant when talking about "lean" and "lateral loading" in
context of steady state turning for two wheel, single track vehicles.
This is in a "high speed" turn, as defined above.

Lateral loading is negligible in "low speed" turns, by definition. The
last time I walked a bicycle up the driveway, the bike followed where I
pointed the front wheel. Was countersteering or high level thought
processes involved? I don't know, but I do know without graph paper or
slide rule that neither was necessary or relevant.

Really, forget the teacher-to-the-stars spiel. What a jackass you must
be, to have needed it as a cudgel in front of a class.

 

<spit take> And all you had to do to counter the effects of gravity
was add 2 feet to the 2 wheels! Newton's ghost must blush at the
mention of your name...

How would you refer to someone who has apparently not even bothered to
glance at the Wikipedia entry on two-wheeled vehicle dynamics...?

 

I'm saying lean is irrelevant at low speed. Steering geometry suffices.
All you're pointing out is that the external force substituted for the
(unneeded) countersteer. Blush deeply indeed.

Did Newton use Google to investigate his apple phenomenon? I say thee
nay. His observations pre-date the lightweight wikipedia collection of
knowledge. (I'll take a peek later. Sounds cool.)

 

You've only just worked that out?

 

No, you said walking a bike is identical to riding a bike.

Give your bike a shove down a grade, let go and measure how long the
steering geometry keeps it upright.

No, I pointed out when one walks a bike they hold it up instead of
relying on balancing against gravity.

He was smart, you're stupid.

Fascinating... and awfully convenient for the Wikipedia to have those
observations to reference!

Excellent choice of timing...

 

(Mildly) You seem to be confused: nobody said
anything about being a "teacher to the stars", nor was
there anything about "cudgeling" a class. Making up
your own facts tends to get you laughed at on Usenet.

(My! The man completely misunderstands the physics
of a moving motorcycle, and appears to be proud of it!
The interweb is full to overflowing with examples of the
Dunning-Kruger Effect!)

 

(Sigh) It isn't. And it doesn't.

Unless you have feet paddling along the ground to hold
you upright, you turn your motorcycle exactly the same way
at low speeds as at high: you intitiate the turn by
countersteering, and as the bike falls into the turn you steer
into the turn enough to keep the bike from falling over to the
inside of the turn.

If you try to turn a motorcycle any other way it will fall
right over, and that's really all there is to it.

I should have known. First the "I already know all
about the subject" followed by "Google doesn't know
anything anyway".

 

Gee!

I didn't know you felt that way about me!

~Pete

 

I hate doing this, but I agree 100%. If instead of a bicycle, you
picture the much more considerable mass of a motorcycle, the need to
balance upright trumps contact patch dynamics and steering geometry.
Retracted...

Don't start.

 

Damn. Sorry about that. MacSoup auto-kills the posts after 14 days and I
didn't read the attributions properly. Thought it was Shumman he was
replying to.

<Thinks>

Na,h fukkit, let the comment stand ;-)

 

Damn cockey -strike that- cockney Brit.

"Harry Potter" sells ten zillion copies and suddeny
they *all* think the Sun shines out of their ass.

 

You might be amused to know that eternal-september, my usenet posting
host, went down and stayed down for 4 days shortly after I posted the
above. Something about it apparently shook the whole fabric of reality.
And on reflecting further, the following came to light.

Upthread, Gpsman had chided me for not bothering to check his definitive
fount of deep learning (wikipedia) before posting. "Spit take", he
wrote. Ptui, I say now in response. In the month in between, I found
time to read the lengthy article, and wondered if anybody else posting
here had bothered to do the same.

There are indeed two speed ranges for bicycle dynamic stability. Six
year olds know this from observation; we all agree that slow speed is
different. The context here, though, is countersteer. Sorry, Pete.
Sherman wins that argument. The bicycle is unstable in the slow speed
range, by definition. Countersteering to enter turns does not apply.

I hope that this now restores the balance in the universe.

 

Off your meds again, I see. Pity.

(But...BUT... *BUT!* It *MUST* be true!

He read it on the web!)

 

Do you want people to hate you?

 

This thread got feisty! Sucks about the test.