I thought it was just another day leaving in the morning to head up to class.
Sure didn't feel like it! http://www.bayarearidersforum.com/forums/images/smilies/rant.gif

tzM3SDrueH0

If I was scanning ahead more, I might have seen the ultra-slick median between the car tire paths.
But alas, it was just a simple on-ramp. I wasn't caring about lines, I just figured that I'd turn and get onto the freeway to go to school.
Wasn't going to try any hooliganisms since it was too close to home meaning the tires were still very much cold.

Boy did I wake up fast! And you can bet that I'll be following a car tire's path through that ramp from now on http://www.southbayriders.com/forums/images/smilies/crash.gif

So this is just a friendly reminder to my fellow riders: don't let your guard down, it just might bite you in the butt!
Oh, and wear your gear. This would have been very painful had I been sporting a pair of jeans and tennis shoes.

That's all I have to say for now. I hope the rest of your guys and gals' new year is off to a better start than mine http://www.bayarearidersforum.com/forums/images/smilies/h.gif

Not too sure if this would go better in Riding Skills or General, so I'll just stick it in General and let Alex figure it out :p

What actually is that in the road that caused you to slide? fuel or something? glad you came off okay how is your bike after it?

That sucks Solomon, but glad your ok. Note taken about not letting guard down too!

Damn man, it pains me to see that happen to anyone. Bet you're gonna feel that in the morning. Best of luck repairing the damage.

yeah wtf happened there? it looked like it just slid out right out from under you :eek:

Ouch! Glad to see you bounced right back up.

My guess would be a combo of cold tires, angle of the turn and the speed as well. Was there also something slick in the road?

good thing a cager wasn't behind you and glad to see you are alright. how cold was the temp outside? looks like you crossed over the slick middle spot of the road where cagers drop oil and coolant.

It looks like someone's radiator or transmission spewed on the onramp. Damn dude...sorry about that. Hope you're ok....I'm sure the bike isn't.

It's nice of you to post this wake up call bro...I fear I might have gotten a bit too complacent with my riding. Anyway, good luck with the repairs.

Is your front tire pretty worn? I can't tell for sure from the video.
Cold (worn) tires will do you in, good thing there were no vehicles following you closely.

Definitely looks like coolant, due to the sheer volume of it. I hit a patch of it while making a left turn at a busy intersection a few years back. My Virago wanted nothing more than to lay down in it. The only time I can remember ever dragging my foot all the way through a corner to keep from falling. A car ahead of me had already taken the corner too fast and went up on the curb at the far side of the corner. Dangerous stuff.

There are few worse sounds than a bike sliding along the pavement. Hope the damage isn't too bad.

Glad you're OK, Solomon!

/moved to crash forum

Aww, that's sad. Your bike looks so clean and well looked after too.

yeah. twisty on ramps and offramps are the worst. they always have toooons of oil in the middle toward the outside. ive almost lost it more than a few times from oil in on/off ramps like that. good that you and the bike are relatively ok. bet you wont make that mistake again ;)

yeah. twisty on ramps and offramps are the worst. they always have toooons of oil in the middle toward the outside. ive almost lost it more than a few times from oil in on/off ramps like that. good that you and the bike are relatively ok. bet you wont make that mistake again ;)

What mistake was that though? Riding in the middle? I just can't see myself doing anything different if I were in his place...I think he was just bloody unlucky that day.

I don't say this from experience (I'm still a little noob!), it's purely something I read (Keith Code again), but... if you had been applying more smooth and gradual acceleration during the turn, thus loading the rear wheel more than the front, do you think you would have made it through? It didn't look like you were accelerating through the turn.

What d'ya think?

akima - he hit a big patch of oil. if his front didnt go his rear would have. if he was lucky he could have over steered it out but that can lead to some scary situations once you get passed the oil.


EthioKnight - the mistake was riding into a visible patch of oil. it was visible before he got there, but he rode directly into it. its possible the patch didnt register because he said he was on "auto-pilot" but you should always expect there to be oil on well used curves like that. leaky trucks drop their pooled up oil when they take those turns and it dumps the oil in the middle and toward the outside of the road. if you see what looks like oil where you expect to see oil, chances are its probably oil.


btw- big black streak going down the center of asphalt = oil. (or at least, something you dont want to drive through)

if you see what looks like oil where you expect to see oil, chances are its probably oil.

I pictured you sat with your legs crossed, stroking your long grey beard while saying that. :p

Darn! That's a hard fall. I hope you're ok, and your vstrom.

I pictured you sat with your legs crossed, stroking your long grey beard while saying that. :p

:( its not all grey...

Thanks for the move, Alex. Not sure why I didn't see the crash forum when I was scrolling up and down. Guess it goes to show that I need to spend more time on the ninjette forum. My ninjette is sitting in the garage not wanting to spark right now. Maybe now that it's finally raining I'll get around to figuring it out :D





akima - he hit a big patch of oil. if his front didnt go his rear would have. if he was lucky he could have over steered it out but that can lead to some scary situations once you get passed the oil.


EthioKnight - the mistake was riding into a visible patch of oil. it was visible before he got there, but he rode directly into it. its possible the patch didnt register because he said he was on "auto-pilot" but you should always expect there to be oil on well used curves like that. leaky trucks drop their pooled up oil when they take those turns and it dumps the oil in the middle and toward the outside of the road. if you see what looks like oil where you expect to see oil, chances are its probably oil.


btw- big black streak going down the center of asphalt = oil. (or at least, something you dont want to drive through)

Alex hit the money on the dot. Another forum seems to agree that it was most probably extra fluid from one of those catering trucks as they have a tendency to dump water from their bins when turning tight turns thanks to the centrifugal effect.

Either way, hit a patch of slickness while turning, be it oil, black ice, whatever, it is incredibly hard to save it. Best course of action is to avoid it in the first place. Obviously it was caught in the video so I should have seen it, but I didn't think I needed to be hyper-sensitive since it's a ramp I navigate everyday.





Originally, I was just going to leave the video to those who see it on my facebook. But one friend sent me a message encouraging me to post to the forums, and it made sense since there's the good chance that some others might also benefit from my mishap. And it looks like the message has gotten out to others, so hopefully less people make the same mistake as me

For those of you who are curious, this is how the bike looked after I got it up and just before I took off.

fET3hPu8bVg

I stopped by my insurance agent's office after work to have a chat about numbers and to bring my R6 back to full coverage (dropped to state minimums when insuring the Strom since I wasn't planning on riding it for a long time as I was having a grand old time with the Strom and the R6 could use some winter maintenance love). I then rode the Strom back to my house in San Jose so that I could take my R6 back for school today since I heard that the storm was supposed to get worse. Left home at 5:40 to come back to Santa Cruz and nearly went head-on into a truck that didn't see me. Had to cross two big painted arrows to avoid them, hence why I didn't slam on the brakes (wet weather + painted surfaces = horrible traction).

lOacjUnyPjM

I already had some auxiliary lights on the R6, but I guess it isn't enough. More lights was already on the list of near-future purchases for the Strom. Anybody have a good deal on Clearwater Lights? http://www.r6-forum.com/forums/images/smilies/sing.gif

A crash and a close-call in a span of..what?...2 days?
You lead an eventful life sir. (nominated for the understatement of the year awards).

Painful to watch. Good luck with repairing the bike. Again, painful.

Really close call in other video.

Man, that hurt a little bit on the inside.....Glad to see your okay though! :D

As a new rider, this gives me a lot to think about. With only 2000 miles under my belt, once in a while I catch myself being a little too self-confident already, which is scary...

Glad you are ok!

That sux but I am glad you are ok.

My guess would be a combo of cold tires, angle of the turn and the speed as well. Was there also something slick in the road?That's my guess. Looked like he wasn't accelerating enough, to boot.

Though I do love how your reaction to the crash was something along the lines of "Huh. Well, that just happened." :p

Sorry for the noob-iness of my question: What is the point of using a helmet cam?

i layed mine down this summer,
It was a light rain and my car was broken. stopped behind a suv and the bike when from under me. dam came close to the suv and the traffic on the other side. the fall was the same as yours. bruised my knee and shoulder.
couldn't move my arm around without feeling some discomfort for weeks. got water on the knee after 2 week.
shifter pedal snapped off. was in a daze though i couldn't drive it home. (only to realize that i could of shifted into 1st and use the clutch) was only 1 mile from home. had to trailer it.
i am starting to think it is the tire.
bike was new. less then 1000 miles.
i had issue with stopping and it sliding.
but my katana and fzr600 didn't have problems (with braking) (if they worked)
i am currently upgrading the bike. might get better tires.

Sorry for the noob-iness of my question: What is the point of using a helmet cam?
Evaluate skills, share your ride with others, record evidence in case of a crash... could be a dozen different reasons.

Hey Solomon are you rocking your cam right on the top of you helmet?

Not sure what happened here, but hope your ok. I'm a new rider so I take it nice and easy on the turns. One thing I noticed you did which I thought was a no no was take the turn on the inside. I always take the turn on the out then come in like they told me in the MSF class. Slow in the turn and fast out.

Well, that's how you do it. But it didn't really matter, because he would've made that turn, if the oil wasn't there. Maybe, if he did take it out-in-out then he would've made it, but he was zoned out. It happens.

Not sure what happened here, but hope your ok. I'm a new rider so I take it nice and easy on the turns. One thing I noticed you did which I thought was a no no was take the turn on the inside. I always take the turn on the out then come in like they told me in the MSF class. Slow in the turn and fast out.

it varies based on conditions. no turn is ever the same. even the same turn night vs day or one day to the next.

I always take the turn on the out then come in like they told me in the MSF class.

That does not apply to the conditions he faced.

Fluids dropped on the road tend to be towards the middle-outer of the curve.

Centrifugal force does it, just like with the bike after falling.

Note how traction was good on the inside of the curve (cleaner area) and how it failed as soon as he drifted onto the center.

Hard for him to have seen it from the distance, but you can see in minute 11 (just before the lost of traction) that something dripping fluids had been dragged from the center to the right of the lane.

Centrifugal force does it, just like with the bike after falling.

huh?

after falling, the bike is going in a straight line that is tangent to the curve at the point that it fell. It has forwards velocity, and there is nothing making it turn, so it will go in a straight line from where it went down. It only goes to the outside of a curve because the road continues to turn, and the bike continues in a straight line

"centrifugal" force is the inertial effect that you feel based on the centripetal acceleration of turning. Centripetal force is the force that keeps objects turning in to the center of a circle. "Centrifugal" force is a made-up force that we use so we can explain the effects of the centripetal force from a non-inertial frame of reference. (aka we feel the "centrifugal" force when in a car around a turn, but in reality, there is no force pushing us outward; it is our own inertia that we feel because the car is turning and our bodies want to continue in a straight line.)

Stand corrected:

The fluids that fall from a moving vehicle, once not under the influence of the centripetal acceleration or having nothing to make them turn, follow a falling straight line that is tangent to the curve, finally splashing over the road towards the middle-outer of the curve.

Avoid riding over that area in turns and turn-arounds', especially if the road is wet, because your tires may suddenly loose the effects of the centripetal force, having nothing making them, the bike and yourself follow the curve.

Stand corrected

Sorry dude. I hope I didn't come across as a jerk there. I was just in the middle of my physics hw and I had my nerd on. ;)

Nothing to be sorry about, you were correct; we are good.

Because action and reaction forces must be equal, as long as a mass is forced to travel describing a circle, that mass resists that deviation by tending to keep the straight trajectory. Both balanced forces (towards the center of the circle and away from it) are equal to the product of the mass and the centripetal (or normal) acceleration.
At the moment the disturbing force disappears, the reactive force disappears as well, and the mass resume straight movement.

That acceleration depends on the square of the tangential velocity and the inverse of the radius at=Vt^2/r.
That acceleration is created by the front tire rolling perpendicularly to the center of the circle (forcing the center of mass to deviate from a straight line).
The centrifugal force or reaction appears at the center of gravity, which happen to be higher than the tires patch.
Then, we have to lean the bike enough to balance that moment that tries to turn the bike over.

That centripetal acceleration and associated force (F=ma) is the reason for which curves must be initiated at moderated velocity: any increment of speed means a proportionally square increment of the force that is trying to make your tires slide away from the circular trajectory, while the force that tries to keep them planted on the road only depends on the weight of the bike-rider and the asphalt-rubber friction coefficient.

What happened in the case that we are discussing is simply that the friction coefficient suddenly decreased (when the OP hit that slippery spot).

idk what the **** you guys are even talking about...

Great use of the crash forum, and of helmet cam. Useful reminder about complacency and the reality that road conditions today can be very different from road conditions tomorrow. Thanks for sharing such a great video reminder with us. :thumbup:

Nothing to be sorry about, you were correct; we are good.

Because action and reaction forces must be equal, as long as a mass is forced to travel describing a circle, that mass resists that deviation by tending to keep the straight trajectory. Both balanced forces (towards the center of the circle and away from it) are equal to the product of the mass and the centripetal (or normal) acceleration.
At the moment the disturbing force disappears, the reactive force disappears as well, and the mass resume straight movement.

That acceleration depends on the square of the tangential velocity and the inverse of the radius at=Vt^2/r.
That acceleration is created by the front tire rolling perpendicularly to the center of the circle (forcing the center of mass to deviate from a straight line).
The centrifugal force or reaction appears at the center of gravity, which happen to be higher than the tires patch.
Then, we have to lean the bike enough to balance that moment that tries to turn the bike over.

That centripetal acceleration and associated force (F=ma) is the reason for which curves must be initiated at moderated velocity: any increment of speed means a proportionally square increment of the force that is trying to make your tires slide away from the circular trajectory, while the force that tries to keep them planted on the road only depends on the weight of the bike-rider and the asphalt-rubber friction coefficient.

What happened in the case that we are discussing is simply that the friction coefficient suddenly decreased (when the OP hit that slippery spot).

I don't know why we have to go down this road in a motorcycle forum. I would prefer to leave all mention of 'centripetals' out of this. My centripetal acceleration is my own damn business, thank you very much.

Lovin' the geek talk from choneofakind and Motofool ;)

I tried to read but it's too long.

I don't know why we have to go down this road in a motorcycle forum. I would prefer to leave all mention of 'centripetals' out of this. My centripetal acceleration is my own damn business, thank you very much.

:laugh: awwwh but you have to get your geek on!! :p

Just to be clear, my last post on this thread was very 'tongue in cheek'.

250rr I know it was. It was still funny.

Coincidentally, my HS physics teacher grew up in Portland Oregon also

while the force that tries to keep them planted on the road only depends on the weight of the bike-rider and the asphalt-rubber friction coefficient

Isn't 'wind' an additional force at play here? It can push the bike downwards further planting it on the road and it can push the side of the bike when there are strong cross winds which reduce the "friction coefficient"??

Just to be clear, my last post on this thread was very 'tongue in cheek'.

I got that. I think most people would have got it.

Not unless that was one seriously huge wind. It that case, the wind would only lower the grip because of the extreme lean angle and the fact that as you lean over, your contact patch gets smaller. Not to mention, then the vertical component the Force of the wind would be higher, also because of the higher lean angle. More variables than just wind and grip.

The wind would have no effect on the coefficient of static friction between the ground and the tires, however, because that is inherent to the materials in question (in this case, rubber and pavement). The grip might change, but the coefficient of friction won't change unless there is a change in the two materials in contact with each other. For instance, going from rubber tires on cement to rubber tires on ice.

Not unless that was one seriously huge wind. It that case, the wind would only lower the grip because of the extreme lean angle and the fact that as you lean over, your contact patch gets smaller. Not to mention, then the vertical component the Force of the wind would be higher, also because of the higher lean angle. More variables than just wind and grip.

The wind would have no effect on the coefficient of static friction between the ground and the tires, however, because that is inherent to the materials in question (in this case, rubber and pavement). The grip might change, but the coefficient of friction won't change unless there is a change in the two materials in contact with each other. For instance, going from rubber tires on cement to rubber tires on ice.

In over my head! I'm quite a clever creature, but I don't have the foundation of knowledge required to really understand what you're talking about.

It is not difficult, Akima.

Friction is the force opposed to any movement between two surfaces.

There are two types of friction: static and dynamic; static friction is the force that keeps the tires from sliding over (which is what we have been discussing here; therefore, let's not mess with the dynamic friction yet).

In theory, that static friction force depends only on two things: the type of materials in contact and the force perpendicular to the surfaces (although practice proves it a little different, theory says that even area of contact has no effect on it).

Regarding type of materials: Each combination of materials has a better or worse "grip", which is quantified by a number: coefficient of friction (or frictional coefficient). For rubber over dry-clean asphalt that number is around 0.9 (harder rubber has a lower number or worse grip).
http://www.engineeringtoolbox.com/friction-coefficients-d_778.html

Regarding force perpendicular to the surfaces: that is the total weight over the particular tire (which can be less or more during a ride due to acceleration and braking (see Twist of the Wrist for transfer of mass between wheels)).

In practical terms, all that means that in order to make a tire slide sideways, if rolling (vertically or leaned) over dry-clean asphalt and supporting a vertical weight of 300 lb, a force above 300 x 0.9 = 270 lbs needs to applied sideways.

A crosswind wouldn't affect either one of those factors related to friction, but it would add to the forces trying to slide the bike out of the curve, if blowing from inside the turn.

250rr I know it was. It was still funny.

Coincidentally, my HS physics teacher grew up in Portland Oregon also

Thank you. Portland is a beautiful place to ride. If only the non-raining riding season lasted more than 6 weeks. :p

Isn't 'wind' an additional force at play here? It can push the bike downwards further planting it on the road and it can push the side of the bike when there are strong cross winds which reduce the "friction coefficient"??



I got that. I think most people would have got it.

I have to admit Akima, I have to battle the stereotype that small woodland creatures do not have the mental ability to discern sarcasm. You have my apologies.

To ease my embarrassment, I shall leave extra peanuts in my back yard for you. Please, for your own safety, mind the cat! :D

I have to admit Akima, I have to battle the stereotype that small woodland creatures do not have the mental ability to discern sarcasm. You have my apologies.

To ease my embarrassment, I shall leave extra peanuts in my back yard for you. Please, for your own safety, mind the cat! :D

* nom nom nom *

:p

* nom nom nom *

:p

Viggy says, "Meow".

http://imgs.xkcd.com/comics/centrifugal_force.png

:rotflmao:

hahahahaha very good DSpinler :laugh:


I think Floyd has a good point though. My bad for thread jacking on this one... :o

hahahahaha very good DSpinler :laugh:


I think Floyd has a good point though. My bad for thread jacking on this one... :o

Darrell is fine, or Your Lord Funny Bits (referring, of course, to my Occam-like wit and not to the unmentionables that slam against the tank when I brake too hard) will work.

But seriously Solomon, I'm glad you have survived this most recent encounter with physics in action. Good object lesson for the rest of us.

Oh just because you mentioned that, that's going to be in my mind whenever I see you post :D

You should make that your user title. "Your Lord Funny Bits"

Motofool: thanks for the explanation. That made sense to me.

You are welcome, Akima.

I have found this link about tire grip and road conditions:

http://www.saferrider.org/rider-safety/get-a-grip/