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 Motorcycle Safety
 General Discussion
 Scraping Floorboards During Turns
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Thom Thumb
Advanced Member
1595 Posts
[Mentor]


Jordan, MN
USA

Harley-Davidson

Sportster XL883

Posted - 10/03/2005 :  8:13 PM
HAL, meet Harley. HAL, cut that out . . . (Audio Track: Spracht Zaharathusta rises.)



TT
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howard.v
Male Senior Member
406 Posts


North Bend, OR
USA

Honda

2004 VT750 Aero

Posted - 10/03/2005 :  9:44 PM
quote:
Originally posted by kiddal

If you notice the front wheel is not rotating (or rotating much slower than the rear) in picture number 2. He must have grabbed a bunch of front brake.

Also notice how the bike is doing much better after the bothersome rider has been ejected. It is actually more upright in picture #3!


I noticed that the front wheel wasn't turning. If he had grabbed that much front brake while leaned over that far going to fast through a turn, wouldn't he have flipped the bike over to the left side suddenly? (highside?)
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Mikey
Male Senior Member
287 Posts


Benton, Kentucky
USA

Harley-Davidson

FLHTCI/XL/FXDL

Posted - 10/03/2005 :  10:33 PM
Another case of staged photos going wrong?
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James R. Davis
Male Administrator
17380 Posts
[Mentor]


Houston, TX
USA

Honda

GoldWing 1500

Posted - 10/04/2005 :  8:09 AM Follow poster on Twitter  Join poster on Facebook as Friend  
quote:
I noticed that the front wheel wasn't turning. If he had grabbed that much front brake while leaned over that far going to fast through a turn, wouldn't he have flipped the bike over to the left side suddenly? (highside?)


Not at all. It would have resulted in his front-end washing out, increasing the lean into the turn, grinding his floorboard HARD into the asphalt - and TOSSING him off the bike INTO the turn. (He did not just bail off that bike.)
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James R. Davis
Male Administrator
17380 Posts
[Mentor]


Houston, TX
USA

Honda

GoldWing 1500

Posted - 10/04/2005 :  9:02 AM Follow poster on Twitter  Join poster on Facebook as Friend  
I want to address technique in this message - good and bad - and then suggest a likely chain of events that caused this accident.

The first picture shows the PRIMARY error in technique used by this rider. He was leaning AWAY from the turn which caused his bike to have to lean more into the turn than was necessary and resulted in his scrapping his floorboards. But at that point he still did not have to lose it - he could have saved it at that point. Scrapping pegs or floorboards are a warning that you must not increase speed or tighten your turn, not an announcement of imminent catastrophe.

In the first picture you also notice Mr. Macho riding without proper riding apparel. Not for me to decide that he couldn't afford to lose the skin on his arms - he made that decision (you should feel perfectly free to show all the skin you believe you can afford to lose.)

He was wearing a helmet - though it was a shorty - and some form of eye protection - and gloves and boots. He did some things right. By the third picture you might be wondering how much skin he lost and whether or not he landed on his face, then you could pretty much determine how effective his shorty was in protecting his face.

In the first picture you can also observe that he did not lose control of his left grip - he gave it away! Mr. Macho was pointing at(waving) and posing for the camera. By the second picture you observe that he had regained control of his left grip. But by then he was no longer relaxed and enjoying his ride. His left arm is LOCKED rigid in a wing formation and he is trying to muscle his way through the turn. And then, of course, he panicked and grabbed a handful of the front brake and locked his front wheel. Notice that he is still leaning AWAY from the turn - which made it virtually impossible for him to complete that turn without an accident.

As to leaning while in a turn - you should almost always keep your body IN-LINE with your motorcycle in a turn. Leaning AWAY from the turn increases bike lean angle and increases the odds of dragging a peg while leaning INTO the turn (a racing posture) keeps the peg higher off the ground but IT GIVES AWAY YOUR ONLY SAFETY RESERVE. When your peg starts to scrape you THEN lean your body INTO the turn to lift that peg off the ground and continue your ride. If you are already leaning INTO the turn when the peg drags you have nothing left with which to recover from the event.

The only good technique visible in these pictures is that in the second picture Mr. Macho, though jaw clenched and locked rigid still leaning AWAY from the turn, he did not stick his left knee into the wind hoping to lean even farther AWAY from the turn - he kept his knees tight against his tank right where they belong!

When the front wheel locked the front-end of the bike washed out - even momentarily - and that caused the bike to lean HARD into the turn and its floorboards. That tossed the rider INTO the turn and off his bike. He lost control of both his left grip and his front brake at that point and the front tire began to spin again as he was still in the air.

If there had been a fourth picture you would have seen the bike RIGHT ITSELF and begin to move in almost a straight line as it stood straight up. Not from the bounced floorboard, but from the steering geometry (particularly the trail of the bike's front-end). Motorcycles, when moving, ALWAYS try to go in a straight line, vertical which means that they try, AUTOMATICALLY, to correct your dumb mistakes.

What caused this accident? It was not posture. It was not going too fast. Both of those contributed to the accident but did not cause it. What ultimately, to my mind, caused the accident was the panic of the rider which resulted in him grabbing a handful of brake and 'freezing'. Mr. Macho 'lost it' because he had no idea what he was doing or how to recover from a scrapping floorboard.

'Riding smart' is not just a phrase that sounds good - it is how you will avoid almost every accident.

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timbo
Advanced Member
594 Posts


Uxbridge
United Kingdom

BMW

R1100S

Posted - 10/04/2005 :  9:47 AM
I would disagree modestly with James's analysis, although in the end it don't much matter.

What I think is happening is that the overall geometry of the bike is such that leaning over to the degree he is doing has caused the footboard to dig in and LIFT the front wheel off the ground. Fairly obviously, once this has happened you're a gonner whatever you try to do. It is not clear if he has "grabbed" the front brake or not - it would only take a very modest application to stop the fron wheel whilst it is in the air.

On sportsbikes, which have a more feet backwards type geometry, it is the rear wheel that lifts if something digs in (peg, exhaust, sidestand) . This is marginally less terminal.

Tim
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don_hud
Advanced Member
1077 Posts
[Mentor]


Houston, Texas
USA

Yamaha

1997 Virago XV1100

Posted - 10/04/2005 :  10:35 AM
I'm not sure where these pictures were found. I did some searching for video and have not been able to find much. I had thought that the pictures might have been taken from a video which might make it easier to see and follow what the rider did or didn't do.

But depending on the shutter speed if they were taken with a still camera, it appears from one of the pictures that the rear tire tread is a blur, and the front tire tread is sharp, indicating that the front wheel is turning much slower than the rear. It is hard to tell if the front wheel is locked up, but it appears that he is pretty hard on his front brakes and that is going to affect his handling of the bike. If there is a video, it might tell us more.
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scottrnelson
Advanced Member
6950 Posts
[Mentor]


Meridian, ID
USA

Honda

XR650L, 790 Adv R

Posted - 10/04/2005 :  11:02 AM
quote:
Originally posted by don_hud

I'm not sure where these pictures were found. I did some searching for video and have not been able to find much. I had thought that the pictures might have been taken from a video which might make it easier to see and follow what the rider did or didn't do.


Normal photo resolution for standard video is 640 x 480 (actual video is more like 725 x 525). The photos are quite a bit bigger than that, so they didn't come from video.
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howard.v
Male Senior Member
406 Posts


North Bend, OR
USA

Honda

2004 VT750 Aero

Posted - 10/04/2005 :  11:20 AM
Ok James. Thanks for that explanation. I think the riders first mistake after not wearing more appropriate gear was posing for the camera and not paying more attention to his riding. Hopefully there wasn't an unseen car that came around that turn and ran the rider and/or bike over. Could have been worse than it already appeared.
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SteveS
Male Advanced Member
1208 Posts
[Mentor]


Toronto, Ontario
Canada

Harley-Davidson

2018 Tri-Gliide

Posted - 10/04/2005 :  11:42 AM
How can I download those three photos?
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don_hud
Advanced Member
1077 Posts
[Mentor]


Houston, Texas
USA

Yamaha

1997 Virago XV1100

Posted - 10/04/2005 :  11:59 AM
If you have a PC, and you are using IE, right click on the picture and select "save picture as"
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capozzir
Senior Member
303 Posts


Leesburg, VA
USA

Honda

GL1800B

Posted - 10/04/2005 :  12:05 PM
The picture was likely taken at the Dragon. There is a company that takes high resolution digital pictures of motorcycles going around various turns and then sells them to you later.

I suspect that James is correct about panicking when the floor board made contact. I suspect that the next piece to touch after the floor boards would be the engine guards. The boards touching won't cause a low-side (unless your standing on the inside). Now if those engine guards touch down and enough weight is put on them, you got problems.

Oh, and James isn't kidding about bikes wanting to continue on their own. I was on a race track coming out of the last turn to go down the straight and I lowsided near the exit of the turn (my mistake ). Well after dumping my bum to the track the bike picked itself back up on its wheels and continued straight down the front straight for 100 yrds, crossed the start-finish line and nearly clocked the flag man before it stopped and fell over dead. That was a bad day. I was completely unhurt due to full safety gear. The bike...well....dead.

--Rob
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gary
Standard Member
143 Posts


Kingston, New York
USA

Honda

1100 Shadow '99

Posted - 10/04/2005 :  1:47 PM
My 1100 Ace Tourer corners well w/o pegs touching but my sprite bits all the time. I have put the ruler to boath and they are same off the ground, so, I just don't go as fast on the sprite.
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gary
Standard Member
143 Posts


Kingston, New York
USA

Honda

1100 Shadow '99

Posted - 10/04/2005 :  1:56 PM
Honest, my spelling "IS" better than the last post, forgive me.
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SteveS
Male Advanced Member
1208 Posts
[Mentor]


Toronto, Ontario
Canada

Harley-Davidson

2018 Tri-Gliide

Posted - 10/04/2005 :  2:12 PM
Jim

Thanks for the detailed analysis of what you saw in the photos.

I followed what you were saying about keeping the body in line with the bike and not to panic when a 'big scraping of the pegs' happens. But what I could hear more specifics on is JUST WHAT IS THE BEST YOU CAN EXPECT, when (and if) you find yourself in the same prediciment?

Would you go over this again please.

I hope I do things better 'going in' but I'm not yet perfect and for me MORE KNOWLEDGE = LESS PANIC.

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Indiana Randy
Moderator
2118 Posts
[Mentor]


Fort Wayne, Indiana
USA

Honda

2000 Magna V4 750

Posted - 10/04/2005 :  2:13 PM
Gary, you're a good, prudent and safe rider. You made the right choice.

Nice to have you on board!
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James R. Davis
Male Administrator
17380 Posts
[Mentor]


Houston, TX
USA

Honda

GoldWing 1500

Posted - 10/04/2005 :  2:20 PM Follow poster on Twitter  Join poster on Facebook as Friend  
If you are in-line with your bike when you are in a turn (neither leaning more nor less into the turn than the bike itself is) and you hear/feel a peg begin to scrape then you are being told (DO NOT GO ANY FASTER OR TIGHTEN THIS TURN!) You are not being told that you are about to eat asphalt.

You should at that time move your BODY (not your bike) deeper INTO the turn because the lean angle that was established by your speed and the radius of the turn is through the COMBINED CG of you and your bike - so as you move your body into the turn the rest of the bike stands taller.

In other words, the scraping stops and you continue your turn, probably with a little less throttle.

What you should NOT do in that situation is either chop that throttle or hit your brakes as either action lowers the bike and the scraping becomes a gouging.
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jollyroger
Advanced Member
2157 Posts
[Mentor]


St. Charles, MO
USA

Harley-Davidson

Springer Classic

Posted - 10/04/2005 :  2:27 PM
quote:
Originally posted by James R. Davis


You should at that time move your BODY (not your bike) deeper INTO the turn because the lean angle that was established by your speed and the radius of the turn is through the COMBINED CG of you and your bike - so as you move your body into the turn the rest of the bike stands taller.


What you should NOT do in that situation is either chop that throttle or hit your brakes as either action lowers the bike and the scraping becomes a gouging.



Just a little more clarity, please...
By saying "move your body deeper into the turn", does that mean, in the case of our hapless rider, that he'd lean more to the right or left, that is, toward or away from the inside of the turn?
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James R. Davis
Male Administrator
17380 Posts
[Mentor]


Houston, TX
USA

Honda

GoldWing 1500

Posted - 10/04/2005 :  2:29 PM Follow poster on Twitter  Join poster on Facebook as Friend  
He should have leaned his body INTO the turn (to the right).

Maybe this will help. The drawing on the left shows a rider that is remaining IN-LINE with his bike leaned over at about 45 degrees. The right peg is about to scrape. The drawing on the right shows the rider leaning his BODY INTO the turn. Note that the bike then stands taller (has less lean angle) and the combined CG stays exactly where it had been before. The right peg, as you can see, is no longer about to scrape - it has been lifted off the pavement.



This is exaggerated in order to show the concept. The rider has leaned, say, 15 degrees INTO the turn which causes the bike to lean, say, 10 degrees AWAY from the turn in order to keep the combined CG EXACTLY where it was before the rider's lean.

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kiddal
Male Advanced Member
1561 Posts
[Mentor]


SE, Indiana
USA

Kawasaki

KLR650

Posted - 10/04/2005 :  2:31 PM
quote:
Originally posted by timbo

It is not clear if he has "grabbed" the front brake or not - it would only take a very modest application to stop the fron wheel whilst it is in the air.

It is clear, however, that it was too much brake for his available traction regardless of which verb is used to characterize it.

It's hard to tell because of the different angles of the pictures, but it looks like to me the front end is very compressed in picture #2. I think he was on the brakes pretty hard.

Edited by - kiddal on 10/04/2005 3:00 PM
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