Physics at its best: tank slapper

Motofool · May 13th, 2013, 01:15 PM

Forward to 1:13

Link to original page on YouTube.

Very loose translation (apologies to our Esperanto speaking members): "Scary bars shake from several angles. There are days with and days with no luck, this was a day "with" ..... (since there was no fall to deplore). Is life a miracle?"

Brother Michigan · May 13th, 2013, 01:20 PM

He didn't need those boxers, anyhow...

CC Cowboy · May 13th, 2013, 04:45 PM

How do you get someone to volunteer for that?

Snake · May 13th, 2013, 05:27 PM

Cool video!

cuz · May 13th, 2013, 05:35 PM

yee haw!!!!

Aurodox · May 13th, 2013, 08:20 PM

What caused it? Did he use the front brake while turning or did the front just slip out from under him?

Aggrotech · May 13th, 2013, 08:41 PM

think id rather get hit by a car then to go through a tank slapper D:

Bob2010 · May 13th, 2013, 09:32 PM

Soooo I didn't really know what a "tank slapper" was until this thread

I started to google and that led me to YouTube
About 2:15 in , if that happens to me, and I recover it , bike is going up for sale

http://www.youtube.com/watch?v=lrNqr...e_gdata_player

Motofool · May 14th, 2013, 10:53 AM

Quote:

Originally Posted by Aurodox

What caused it? Did he use the front brake while turning or did the front just slip out from under him?

The oscillations started after a bump upset the suspension and the steering.

Since the steering's pivot line hits the road ahead of the contact patch, the whole steering-front suspension-wheel is a pendulum (being the trial the equivalent to the string of the pendulum).

http://en.wikipedia.org/wiki/Bicycle...cycle_geometry

http://en.wikipedia.org/wiki/Speed_wobble

For that reason, any substantial lateral force on that patch initiates an oscillation.

That oscillation can die by itself or can be magnified by other forces, like the natural resistance from our arms and the inertial effect of our wobbling butt.

Please read this great article:

http://69.46.28.106/forum/17-ride-re...ype=raw#533123

...........and watch this video:

http://www.ninjette.org/forums/showthread.php?t=121404

Joshorilla · May 14th, 2013, 11:07 AM

Gotta wheelie your way outta that bro.

Nemesis · May 14th, 2013, 11:17 AM

I hate it when people intentionally move their handlebars back and forth and record it on vid and claim tank slapper.

dfox · May 14th, 2013, 11:42 AM

i had a very bad slapper about 3 months into riding... on a highway, at dawn, in rush hour, traveling about 70 mph. Changing lanes to the right, while in a right hand bend so I was leaning quite far over, and hit a very large pothole. rear wheel was fish-tailing around. I pulled off the road and took a breather, the guy in the car behind me stopped to see if I was okay.

only reason I saved it, was because I did nothing. The force of the slapper ripped my hands off the handle bars and I fell forward onto the tank. My tail bag completely fell off the bike, and it's on there with four very tight bungees.

I thought I was going to die.

akima · October 27th, 2013, 11:54 PM

@dfox: that sounds really horrible. It's probably worse because most of your control of the bike is sitting on those handlebars that you just got chucked off of.

The thing that I find myself concerned about when something sketchy happens to me, is not so much the potential crash I'm about to experience but the driver behind me. I feel like so many drivers are so inattentive that by the time they react if I come off my bike, their wheels might already running over me. I see people all the time driving so close to the vehicle in front of themselves and barely paying attention.

dfox · October 28th, 2013, 03:32 AM

Quote:

Originally Posted by akima

@dfox: that sounds really horrible. It's probably worse because most of your control of the bike is sitting on those handlebars that you just got chucked off of.

The thing that I find myself concerned about when something sketchy happens to me, is not so much the potential crash I'm about to experience but the driver behind me. I feel like so many drivers are so inattentive that by the time they react if I come off my bike, their wheels might already running over me. I see people all the time driving so close to the vehicle in front of themselves and barely paying attention.

that's what scared me the most... the people that were behind me. Thankfully the guy behind me was pretty far back, and nice enough to stop to see how I was doing, so I'm sure he saw what happened. The car in the adjacent lane slowed down as well. Thing is, I know how bad that section of road is, I should have been traveling more cautious. It's right at the start of a raised highway. There's tons of expansion joints, and the concrete surface is patched and has pot holes all over the place. The expansion joints stick up from the road surface too. It really needs to be re-paved, but it's on one of the most major highways into boston that sees dead stop traffic at 6am from rush hour, little opportunity to re-pave.

It was amazing to me though, that the bike righted itself. The only thing I did was squeeze my legs as hard as I could, since that was the only positive connection I had to the bike. I wish I had taken a photo of it, but I had scrapes at about a 45 degree angle on my rear tire.

CC Cowboy · October 28th, 2013, 09:13 AM

Was that on a unicycle?

Foolproof · November 7th, 2013, 06:46 PM

Happened to me on the free way when the tire got caught in a rivet going 90mph... Stopped riding for 3 weeks.. Just can't do anything and let it work itself out..

Happened about my 3rd month riding..

May 13th, 2013, 01:15 PM	#1
Motofool Daily Ninjette rider Name: Hernan Location: Florida Join Date: Mar 2011 Motorcycle(s): 2007 Ninja 250 Posts: A lot. MOTY - 2016, MOTM - Dec '12, Jan '14, Jan '15, May '16	Physics at its best: tank slapper Forward to 1:13 Link to original page on YouTube. Very loose translation (apologies to our Esperanto speaking members): "Scary bars shake from several angles. There are days with and days with no luck, this was a day "with" ..... (since there was no fall to deplore). Is life a miracle?" __________________________________________________ *Motofool* *.................................Never ride faster than your guardian angel can fly* "Mankind is composed of two sorts of men — those who love and create, and those who hate and destroy. Love is the bond between men, the way to teach and the center of the world." - José Martí

May 13th, 2013, 01:20 PM	#2
Brother Michigan ninjette.org sage Name: Aaron Location: Winder, GA Join Date: Jun 2012 Motorcycle(s): 2013 Ninja 300 Posts: 718	He didn't need those boxers, anyhow...
	1 out of 1 members found this post helpful.

May 13th, 2013, 04:45 PM	#3
CC Cowboy ninjette.org certified postwhore Name: Whodat Location: Ware Is.,MA Join Date: Jan 2009 Motorcycle(s): I pass the wind! Posts: A lot. MOTM - Mar '13, Jun '14	How do you get someone to volunteer for that? __________________________________________________ If everything seems under control; you're just not going fast enough!

May 13th, 2013, 09:32 PM	#8
Bob2010 ninjette.org sage Name: Bob Location: NY Join Date: Jul 2012 Motorcycle(s): 2010 Ninja 250 2009 Ninja 250 Posts: 730	Soooo I didn't really know what a "tank slapper" was until this thread I started to google and that led me to YouTube About 2:15 in , if that happens to me, and I recover it , bike is going up for sale http://www.youtube.com/watch?v=lrNqr...e_gdata_player __________________________________________________ 2010 Red Ninja 250 2009 Black Ninja 250 -If you ride like lightning,you're gonna crash like thunder-
	1 out of 1 members found this post helpful.

May 14th, 2013, 11:17 AM	#11
Nemesis CVMA #74 WSMC #750 Name: Nemesis Location: On the track Join Date: Oct 2009 Motorcycle(s): All of them Posts: A lot.	I hate it when people intentionally move their handlebars back and forth and record it on vid and claim tank slapper. __________________________________________________

May 13th, 2013, 05:27 PM	#4
Snake ninjette.org certified postwhore Name: Rick Location: Alexandria, Louisiana Join Date: Jan 2009 Motorcycle(s): 05 Blue Ninja 250 Posts: Too much. MOTY - 2017, MOTM - Jan '19, Oct '16, May '14	Cool video!

May 13th, 2013, 05:35 PM	#5
cuz cuz Name: Israel Location: Houston (me) Galveston Join Date: Jul 2011 Motorcycle(s): 09 ninja 250r Posts: A lot.	yee haw!!!! __________________________________________________ THE GOOD LIFE

May 13th, 2013, 08:20 PM	#6
Aurodox ninjette.org member Name: - Location: - Join Date: Mar 2013 Motorcycle(s): - Posts: 139	What caused it? Did he use the front brake while turning or did the front just slip out from under him?

May 13th, 2013, 08:41 PM	#7
Aggrotech ninjette.org sage Name: Justin Location: Fresno CA Join Date: Jun 2012 Motorcycle(s): 12' Ninja 250 Posts: 831	think id rather get hit by a car then to go through a tank slapper D:

May 14th, 2013, 11:07 AM	#10
Joshorilla Bass Master General Join Date: Aug 2012 Posts: A lot. Blog Entries: 24	Gotta wheelie your way outta that bro.

May 14th, 2013, 11:42 AM	#12
dfox ninjette.org sage Name: Fox Location: Boston Join Date: May 2012 Motorcycle(s): 08 250R Posts: 881	i had a very bad slapper about 3 months into riding... on a highway, at dawn, in rush hour, traveling about 70 mph. Changing lanes to the right, while in a right hand bend so I was leaning quite far over, and hit a very large pothole. rear wheel was fish-tailing around. I pulled off the road and took a breather, the guy in the car behind me stopped to see if I was okay. only reason I saved it, was because I did nothing. The force of the slapper ripped my hands off the handle bars and I fell forward onto the tank. My tail bag completely fell off the bike, and it's on there with four very tight bungees. I thought I was going to die.
	1 out of 1 members found this post helpful.

October 27th, 2013, 11:54 PM	#13
akima Nooblet Name: Akima Location: England Join Date: Jul 2011 Motorcycle(s): 2011 Ninja 250R FI Posts: A lot. Blog Entries: 5 MOTM - Oct '13	@dfox: that sounds really horrible. It's probably worse because most of your control of the bike is sitting on those handlebars that you just got chucked off of. The thing that I find myself concerned about when something sketchy happens to me, is not so much the potential crash I'm about to experience but the driver behind me. I feel like so many drivers are so inattentive that by the time they react if I come off my bike, their wheels might already running over me. I see people all the time driving so close to the vehicle in front of themselves and barely paying attention.

October 28th, 2013, 09:13 AM	#15
CC Cowboy ninjette.org certified postwhore Name: Whodat Location: Ware Is.,MA Join Date: Jan 2009 Motorcycle(s): I pass the wind! Posts: A lot. MOTM - Mar '13, Jun '14	Was that on a unicycle? __________________________________________________ If everything seems under control; you're just not going fast enough!

November 7th, 2013, 06:46 PM	#16
Foolproof ninjette.org newbie Name: Matt Location: Canyon Lake Join Date: Nov 2013 Motorcycle(s): Ninja 300 Posts: 6	Happened to me on the free way when the tire got caught in a rivet going 90mph... Stopped riding for 3 weeks.. Just can't do anything and let it work itself out.. Happened about my 3rd month riding..
	1 out of 1 members found this post helpful.

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