Had my first accident, hope to gain insights into cornering

[Erci]

What is this about getting tickets for being in CoW? Sometimes I do that just to get a break from the wind.

I've yet to be reprimanded for shifting off the seat and leaning my upper body into turn and I know I've ridden by officers quite a few times using this technique. Of course this doesn't mean that it can't happen.

Oh wait.. it's the side cases!! They make me look respectable and stuff! :rof:

 

[kenh]

The whole "get a ticket for looking aggressive" thing annoys me. If I'm doing the speed limit, why should it matter if I'm shifting my weight / upper body?

It should not matter. But the reality is that I am not sure there is any other line of work in which a person can be as subjective as a PO. They may give you a warning, ticket or just want to hear a story about why you think they pulled you over. Maybe it's just that the blue FZ-6 looks like its speeding most of the time. :rockon:

 

[Hellgate]

The whole "get a ticket for looking aggressive" thing annoys me. If I'm doing the speed limit, why should it matter if I'm shifting my weight / upper body?

I've had buddy's get Reckless Driving tickets when hanging off. Why? The police officer assumes you're going so fast you need to hang off.

 

[Hellgate]

Imagine Kevin Schwantz showed up at the track today (and no one knew who he was).. they'd probably tell him his body position needed work!

They would!

Like he only made the podium at the Suzuka 8 hour this year.

He just sucks.

 

[Misti]

Without causing a ruckus, hanging off a bike at street speeds isn't needed. In fact it's a quick way to get a ticket. Yes in the perfect, scientific world hanging off, COW, FIFOM (face in front of mirror), etc. makes a difference. If you are riding that fast, you need to go to the track, period.

On the street I am bolt up right. Why? (Yes I've taken the MSF classes, done dozens of track days, and was an Expert class roadracer, placed as high as 5th). Because riding bolt up right allowed me to actually lean the bike a street speeds.

If back in 1982, I could drag peg on a 1973 Yamaha TX500, with Montgomery Ward Mohawk tires (I kid you not), in 2013 on a 2011 Aprilia Tuono APRC with Pirelli Super Corsas, there is no reason for me to hang off. Honestly.

The key is being 1) smooth, 2) consistent in a corner, 3) being a good trail braking, 4) looking through the corner, 5) smooth roll on.

IF you can do those things you are good to go. There is no need to hang off, COW, CROW, etc. Those things will only get you a big fat reckless driving ticket from the po-po.

I'd agree that "hanging off" in the sense of hanging your ass way off the seat and stretching your leg out to try to get a knee on the deck while street riding is not necessary. Too many riders try to do it just to look cool or get a knee down and on the street and at street acceptable speeds it shouldn't be needed.

That being said, the whole point of good body position and "hanging off" is to reduce overall lean angle while riding. So, if you are at a point in your riding where you are scraping a foot peg or other hard parts it may be time to adjust your riding so that you are leaning the bike over LESS and that is done by bringing your upper body over to the inside of the corner. Most of the time this can be done by just letting your body "go with the bike" or moving your upper body over to the inside a bit more but sometimes you need to get your butt over a little as well.

Sitting bolt upright while riding on the street works to a certain point and can be great BP but there may come a time when you need to start hanging off a little (and in the correct way) not just hanging off in an exaggerated manner to look cool.

 

[Susan]

I have a physics question.

If everything else is equal, do a rider's mass and center of gravity affect the amount the rider would need to shift his/her weight relative to the bike around a corner?

The science part of my brain (which might be faulty) tells me a larger rider is getting some of his weight to the inside of the bike around the corner just by having that greater mass present. While a small, light rider might have to shift his weight to influence the lean angle.

Is that wrong? If it is, why?

 

[Water Bear]

I have a physics question.

If everything else is equal, do a rider's mass and center of gravity affect the amount the rider would need to shift his/her weight relative to the bike around a corner?

The science part of my brain (which might be faulty) tells me a larger rider is getting some of his weight to the inside of the bike around the corner just by having that greater mass present. While a small, light rider might have to shift his weight to influence the lean angle.

Is that wrong? If it is, why?

The answer to your question is yes, a fat guy doesn't have to shift his weight as much.

The physics comes either from conservation of angular momentum or from the formulation that a sum of torques is the change in angular momentum.

If you're really curious I might be able to recall the exact details when I get home. At some point I worked out how motorcycles turn from counter-steering to lean induced turning (with the aid of another guy in my department).

 

[Water Bear]

Well I'm home and you haven't asked, but I had this on my mind for a while, so here it is.

Imagine the front wheel of your motorcycle, spinning as you travel along. Now imagine an arrow parallel to the axis of your front wheel (pointing to the left) whose length is proportional to how fast your front wheel is spinning. This, in physics, is called the angular momentum of your front wheel. In the following, when the angular momentum of the front wheel changes directions, the laws of physics dictate that you and your bike have to rotate about an axis parallel to the change. This is conservation of angular momentum.

Imagine you turn your handlebars left. The front wheel turns left, and as such the angular momentum changes direction slightly. Viewed from overhead, the arrow goes from pointing in a 9 o clock direction to about an 8 o clock direction. You can see that, roughly speaking, your angular momentum arrow has had some extra backwards direction added to it. As stated above, this causes you (and your bike, since you are attached to it) to gain a rotation that causes you to roll along an axis parallel to your bike's forward motion. When you stop moving the bars, you stop tipping over. This is counter-steering.

(edit: Have a good explanation)
(edit 2: Torque explanation)
Now that we're leaned over, the weight of the bike and rider together causes a torque. Here's an explanation of the torque to angular momentum law: Torques cause changes in angular momentum. The torque due to weight (or to normal force, depending on where you calculate it) is given by the mathematical cross product, and points directly towards the front wheel. This causes the angular momentum vector of the front wheel to spin about the vertical axis. This causes a rotation about the vertical axis which causes the bike to turn. In particular this is why quarters turn when you roll one along the ground, or why hula hoops don't tip over when you roll them. This is also very like the explanation for gyroscope precession.

At lower speeds, when there's less angular momentum on the wheels, this whole trick won't work. This is why slow moving objects just fall over when you lean them.

I hope this makes some sense.

 

[Susan]

Well I'm home and you haven't asked, but I had this on my mind for a while, so here it is.

I was out with my husband, and we were having a rousing (or befuddling) discussion about physics and cornering, hoping really hard that someone here would have a brain with a functional physics part. Thank you for sharing yours. :cheer:

I hope this makes some sense.

I think it might after I ponder it long enough.

Fortunately, your short answer was easy to understand.

 

[FinalImpact]

Sorry to hear about down time. I just don't like seeing it for anyone. Glad all is well tho!

This is OT, but from driving healthy V8s with lots of torque and posi track rear, those lines even when dry can get a guy in trouble. I apply "over-respect" to avoid issues, but really this quote here captures why I have no down time at the end of season 3....

The key is being 1) smooth, 2) consistent in a corner, 3) being a good trail braking, 4) looking through the corner, 5) smooth roll on.

Also, I second the statement that, there is NO need to hang off on the street. These bikes will do way may than the laws allow just from being smooth and managing your inputs. This past Sunday 20th, came across a bridge into a sharp lefty under the canvas of the trees only to find the road was as wet as could be but I'm looking up the hill and through the corner missing the wet patch. Bam, engine tachs out taking the rear with it, gentle throttle reduction with no other freaky reactions and all is well. It stepped out a good 18" before I could say Cheese! I swear reacting to somethings can be worse than letting it follow its path. Anyway, all was well and I never thought about it again.

As for riding a dirtbike and crashing allot! Everyone SHOULD! I know it it helped me! Then again I started at 8y/old.

 

[Water Bear]

Sorry to hear about down time. I just don't like seeing it for anyone. Glad all is well tho!

This is OT, but from driving healthy V8s with lots of torque and posi track rear, those lines even when dry can get a guy in trouble. I apply "over-respect" to avoid issues, but really this quote here captures why I have no down time at the end of season 3....



Also, I second the statement that, there is NO need to hang off on the street. These bikes will do way may than the laws allow just from being smooth and managing your inputs. This past Sunday 20th, came across a bridge into a sharp lefty under the canvas of the trees only to find the road was as wet as could be but I'm looking up the hill and through the corner missing the wet patch. Bam, engine tachs out taking the rear with it, gentle throttle reduction with no other freaky reactions and all is well. It stepped out a good 18" before I could say Cheese! I swear reacting to somethings can be worse than letting it follow its path. Anyway, all was well and I never thought about it again.

As for riding a dirtbike and crashing allot! Everyone SHOULD! I know it it helped me! Then again I started at 8y/old.

Glad to have the feedback. The more input I get and the more perspectives I have on the same idea the better an impression I form of what the truth may be.

I was out with my husband, and we were having a rousing (or befuddling) discussion about physics and cornering, hoping really hard that someone here would have a brain with a functional physics part. Thank you for sharing yours. :cheer:



I think it might after I ponder it long enough.

Fortunately, your short answer was easy to understand.

I hope it makes some sense! I think it's cool that you and your husband can talk physics.