September 23rd, 2011, 08:10 AM | #1 |
ninjette.org sage
Name: David
Location: Loves Park, IL
Join Date: Feb 2011 Motorcycle(s): Time will tell Posts: 969
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Looking for a study... -- Emergency Stopping
Well, this is vague, and I figured I would ask... After spending the last hour, no luck. Granted, there are tons of articles on this particular subject, but there was one I believe was posted on here.. The topic was Emergency Braking ( or panic stopping, emergency halting, something ambiguous and not direct). Regardless, the focus of the study was braking, with several bikes used (sport, sport tourer, no cruiser I don't think). The conclusion was specific, noting that clutch-in front-braking only without downshifting resulted in the shortest and quickest stop. I've searched (not so ruthlessly, but painstakingly) through this forum and on Google, with no luck. It provided quite a few pictures as well. I don't think it was NHTSA, and I believe it was a European study (hence the ambiguity of the term for 'emergency stop' ). If anyone knows what I'm talking about, you are awesome. |
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September 23rd, 2011, 08:48 AM | #2 |
Smoker
Name: Bob
Location: SoCal
Join Date: Dec 2010 Motorcycle(s): Guess.... Posts: 556
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September 23rd, 2011, 11:40 AM | #3 |
ninjette.org dude
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In the Riding Skills sticky at the top of that section, there are several threads dealing with rear braking. A number of studies are linked from there. I don't think any of them matched exactly with your thoughts, but they were close. The difference between using the rear brake or not using the rear brake in a panic stop, given optimal usage of both the front and rear brakes, was a difference of 5 feet at 150 feet of stopping distance.
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September 23rd, 2011, 11:58 AM | #4 |
There's a limit to s2pdty
Name: A.D.
Location: NoVa the burg
Join Date: Apr 2011 Motorcycle(s): 250r ninja (sold) Posts: A lot.
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I know there's one here in ninjette. cause I remember printing something out here and practicing in at the parking lot. It was a study made in europe or something and then they translated it in english, I'ma try to look for it and I'ma let you know.
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September 23rd, 2011, 09:50 PM | #5 | |||
ninjette.org sage
Name: David
Location: Loves Park, IL
Join Date: Feb 2011 Motorcycle(s): Time will tell Posts: 969
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Quote:
http://mfes.com/motorcyclebraking.html Quote:
Quote:
Thanks for all the help though, guys. I'm wasn't sure if this justified it's own thread, so if it does not, by all means move/merge/delete what-have-you. |
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September 24th, 2011, 01:30 AM | #6 | |
ninjette.org member
Name: Nathan
Location: Portland, Oregon
Join Date: Apr 2011 Motorcycle(s): 2009 V-Strom 650 ABS Posts: 166
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Quote:
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September 24th, 2011, 06:41 AM | #7 |
ninjette.org dude
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People say alot of things.
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September 24th, 2011, 07:23 AM | #8 | |
ninjette.org guru
Name: Anon
Location: Atlanta, GA
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Quote:
Additionally, motorcycles with longer wheelbases (read: cruisers) don't transfer weight as easily to the front because the lever arm to keep the back end down is longer. TBH I'm not sure if it makes enough of a difference for 30% of the braking power to be in the rear, but it's definitely more useful than on a sportbike. |
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September 24th, 2011, 08:50 AM | #9 |
Always.
Name: Alex
Location: Calgary, AB
Join Date: Mar 2011 Motorcycle(s): '08 Ninja 250, '05 GSX-R600 Posts: A lot.
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5% is better than no percent...in any case
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September 24th, 2011, 09:19 AM | #10 |
ninjette.org dude
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That 5% isn't a guarantee. It's an indication that getting the front brake right is most critical. And if you screw up the front brake (not hard enough, too hard and need to let it off and re-apply), then nothing you do with the rear will ever get you those feet back. All of this has been discussed in detail in those rear braking threads from the riding skills sticky.
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September 24th, 2011, 10:16 AM | #11 |
Always.
Name: Alex
Location: Calgary, AB
Join Date: Mar 2011 Motorcycle(s): '08 Ninja 250, '05 GSX-R600 Posts: A lot.
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Front brake is most critical. If you can't front brake properly in an emergency situation, you will not stop efficiently. So yes, agreed.
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September 24th, 2011, 04:10 PM | #12 |
ninjette.org member
Name: Werner
Location: Johannesburg, South Africa
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The reason it's not recommend to use the rear is because the lack of downforce on the back also means you can easily lock up that wheel.
Locking up the wheel can take an already hairy situation over the top even if you DON'T hit anything. That gyroscopic effect helps keep you upright, and the traction from the rear helps keep the bike in a straight line. That said: If you only get 5% of your breaking from the rear, it can still make a healthy difference... That extra 5% also means you stop in a distance roughly 5% shorter. That's the difference of being at the back bumper of a small car or at the front bumper of a car from 100km/h (60mph)... and the distance you have to travel through the car is MUCH harder than travelling the 40m before the car. |
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September 24th, 2011, 06:29 PM | #13 |
The Black Widow
Name: Eva
Location: Brooklyn, NY
Join Date: Jul 2011 Motorcycle(s): 2010 Ninja 250 Posts: 189
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Have any of you actually locked up your tires from emergency breaking? I've been in a few situation where I had to break HARD and my tires never locked up. I almost always use both breaks. The only time I only use the front break is when I'm going slow and have to be ready to stop quickly... mostly to catch my balance if I have to.
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September 24th, 2011, 07:01 PM | #14 |
There's a limit to s2pdty
Name: A.D.
Location: NoVa the burg
Join Date: Apr 2011 Motorcycle(s): 250r ninja (sold) Posts: A lot.
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It is very easy to lock up the ninjette's rear tire, why? because the ninjette is really light.
here's what I do: Emergency stop. I close my throttle, I gently apply the rear brake(to slow down, not to stop) while pulling the clutch in and then I use my front brake to stop. I also make sure that I'm at an upright position/straight body and looking forward. I've read this from the study that I found here on ninjette, some guy posted on some thread. Emergency "slow down" and evade. I use the same technique as my "emergency stop" but I control the clutch and I make sure I'm at the right gear so I can speed off to safety. (I used this technique a couple of times, practicing my emergency stopping skills saved my ass a couple of times from cagers too. ) Slowing down for a turn. I use my front brakes (Like Rossi does) Slowing down to yield. I use my rear break + clutch control + front break if I need to stop. @ leed I'm still looking for the thing, but I can't seem to find it. |
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September 24th, 2011, 09:23 PM | #15 |
ninjette.org member
Name: Nathan
Location: Portland, Oregon
Join Date: Apr 2011 Motorcycle(s): 2009 V-Strom 650 ABS Posts: 166
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Well, by people I was referring to the MSF, Team Oregon, etc... In fact, looking at my Team Oregon book now, it shows a chart with braking distance at highway speed. It lists 180 feet with just rear, 130 feet with just front, and 95 feet with both.
You're saying that is incorrect, and I probably shouldn't bother with my rear brake in a panic stop? (Which, incidentally is my default tactic - I almost never use my rear brake, but I've been trying to work on using it in the hope that I would be more apt to use both in a panic stop.) |
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September 24th, 2011, 10:11 PM | #16 |
ninjette.org dude
Name: 1 guess :-)
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That chart may have some validity for a long-wheelbase heavy cruiser, but it is completely wrong for any modern short-wheelbase sportbike. If you're not bringing the front close to lockup, you're not stopping as hard as you can. If you think you're bringing the front close to lockup, yet the rear end is still weighted down enough that you can apply any significant braking pressure, you're not anywhere close to front lockup.
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September 25th, 2011, 12:00 AM | #17 |
wat
Name: wat
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i removed one of my front calipers the other day... it was weighing me down... plus the rear brake is cooler anyway
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September 25th, 2011, 02:15 AM | #18 | |
ninjette.org member
Name: Werner
Location: Johannesburg, South Africa
Join Date: Apr 2011 Motorcycle(s): EX-250K Posts: 48
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Quote:
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September 25th, 2011, 09:15 AM | #19 | |
ninjette.org guru
Name: Anon
Location: Atlanta, GA
Join Date: Aug 2009 Motorcycle(s): 2008 Ninja 250 (Blue!) Posts: 488
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Quote:
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September 25th, 2011, 10:44 AM | #20 |
ninjette.org member
Name: Werner
Location: Johannesburg, South Africa
Join Date: Apr 2011 Motorcycle(s): EX-250K Posts: 48
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That's motogp with warm super-grippy tyres on very good surfaces, but to be fair a shorter wheelbase would reduce rear grip under hard braking, yes.
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September 25th, 2011, 12:07 PM | #21 |
ninjette.org guru
Name: Anon
Location: Atlanta, GA
Join Date: Aug 2009 Motorcycle(s): 2008 Ninja 250 (Blue!) Posts: 488
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Google "ninja 250 stoppie youtube" and I'm sure you'll see it's no problem
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September 25th, 2011, 01:00 PM | #22 |
ninjette.org member
Name: Werner
Location: Johannesburg, South Africa
Join Date: Apr 2011 Motorcycle(s): EX-250K Posts: 48
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September 26th, 2011, 07:26 AM | #23 | |
ninjette.org guru
Name: Toly
Location: NY
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Quote:
Last year I had the same idea as you in terms of approach to braking, until it started biting me hard later, at higher speeds. I now use front brake only - not having to worry about rear locking up saves precious concentration in an emergency. Now I use rear brake mostly in slow-speed turns and when coasting to a stop light... We should go for a ride soon. |
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September 26th, 2011, 12:47 PM | #24 |
ninjette.org dude
Name: 1 guess :-)
Location: SF Bay Area
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I'm not sure I follow here? The goal isn't to lock the rear wheel; once that happens it's foreseeable that the stop will take much long er as you have to concentrate even harder keeping the bike upright while now modulating the front. If you choose to use the rear in an emergency stop, you need to be sure that you in fact won't lock it, right?
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September 26th, 2011, 12:48 PM | #25 | |
ninjette.org member
Name: Werner
Location: Johannesburg, South Africa
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Quote:
To be fair, I was lane-splitting on broken lines. Car to the right of me changed to the left without indicating, so I got on to the brakes. Rear did an S-shake, although I suspect it hit the painted line as well. While splitting I often have my foot on the brake and have my hand hovering on the other. Might not be much, but even a foot might be enough to make a difference. Didn't even touch the horn, but the car to my left climbed on his as he had to get on the brakes as well and he hammered out a few notes. |
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September 26th, 2011, 12:50 PM | #26 |
ninjette.org dude
Name: 1 guess :-)
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But if you're locking the rear, you're not gaining a foot. Once sliding the coefficient of friction goes right back down. You need to be able to manage both brakes without locking either when trying to stop, and it sounds like you're using too much pedal.
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September 26th, 2011, 01:21 PM | #28 | |
ninjette.org member
Name: Werner
Location: Johannesburg, South Africa
Join Date: Apr 2011 Motorcycle(s): EX-250K Posts: 48
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Quote:
Also - You'll lose the most of the useful gyroscopic effect at about 15mph, and that's reached in less than half a second at slow speeds. --- Taking it in a different light, if my front touched paint, and my rear didn't, I at least would've had braking force on the rear although I might've wiped out the front Braking with just the front wouldn't I have an even higher chance to wipe out if I lose traction on the front? Braking on the rear at least 'pulls' the back of the bike swinging the front towards the direction of motion. |
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