fish_antlers
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posted October 03, 2005 10:48 AM
Can you stoppie with ABS?
??? Well?
   
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k bryant
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posted October 03, 2005 12:08 PM
 Edited By: k bryant on 3 Oct 2005 13:09
Sure why not? You don't have to lock up the wheel to do a stoppie. I think the bike you're doing it on is more of the challange.
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deathpulse
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posted October 03, 2005 12:26 PM
I don't think so... tried on a BMW with ABS... but didn't get to radical. I think the slowing of the rear affects the ability to pull it up?
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CrotchRocket
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posted October 03, 2005 04:37 PM
I bet it's possible...Just need the right technique, since you dont lock the wheel during an endo or stoppie...
The ABS will be perfect, you will never see a guy trying to do a stoppie, locking the wheel and falling...
It will be great for bracket racing, grabbing the brake at 150mph without going down!!!
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Jason Miller StreetBike Seminars
*****DragRacers do it better, because they dont cut Corners*****
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trenace
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posted October 03, 2005 05:55 PM
If the ABS system is lightweight, can be retrofitted, and I can understand how to do it (some systems probably would not allow this idea) I would like to try having the ABS hooked to only one of the front brake lines. I would then have direct control over one caliper with the ABS being unable to affect it, and the other caliper, the ABS could release pressure as it sees fit to help avoid locking.
Might give the best of both worlds -- feel and control of standard, plus a large measure of the super-fast-reflex lock-avoidance assistance of the computer. Interesting to try anyway.
Ultimately there's no reason ABS can't be done where it is ONLY a benefit on the bike -- it is not as if actual locking is ever something beneficial. Apparently no one has quite gotten there yet though. The new BMW system is reported to be not bad except for feel being degraded and except for HAVING JUST ABOUT NO BRAKES when the engine isn't running. (Oops just a minor flaw there.)
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Hells Dark Lord
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posted October 03, 2005 10:10 PM
<-----doesnt do stoppies.......
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When in doubt, lean farther and go faster....
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tuusinii
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posted October 04, 2005 12:36 AM
I'd say that You can't do a stoppie, but You could raise the rear if You still have some speed - so not stopping the bike. That's because in a stoppie the tire dosen't "lock" relatively to ground but relatively to the sensor (its in the front fork) it gets stopped. So the ABS does takes some pressure of.
And Tre, I think that with that setup You'd get worst of both world. Ie, even the one disk would be enoug to lock the wheel and so the ABS could do nothing to You. The features in the BMW don't have anything to do with ABS but with power. It's like in Your car - if Your motor isin't running You need a whole lot of force to try to brake the car. Nowadays the ABS is usually better also in bikes - with regard to stopping the bike in emergency. Thats mostly because You can't lock the feel even when Your not "at Your best". They can still be made better though. But I also think that You still should have the ability to turn of the ABS for some conditions - gravel for example. If and when ABS works good You don't notice it during normal riding it only affects when tires try to lock. Of course there is this trouble of how close of locking can the tires be without losing control.
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lizard
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posted October 04, 2005 01:34 AM
I don't see why you couldn't.
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trenace
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posted October 04, 2005 09:49 AM
Edited By: trenace on 4 Oct 2005 11:09
tuusinii, you might be right, but it also might be right that easing the pressure on one caliper would be sufficient to avoid lockup where one was just modestly overbraking anyway. That would be all I'd want out of it.
I'm not sure what you're saying regarding a stoppie. The front tire by no means stops or locks relative to the fork. It's just engaging in normal heavy braking.
However, if a bike has linked brakes (as some ABS bikes do but presumably not the Kawasaki) then the rear wheel will stop or approach stopping as all weight comes off of it, which would cause release of the brakes, which would put weight back on it. Additionally, where there is no linked braking, if the front wheel is spinning much slower than the rear wheel, this is taken by the ABS as evidence of incipient skidding, causing release of the brake.
So if your rear wheel is still spinning 100 mph, ABS probably would not allow a stoppie to any speed below for example 80 mph, I would think.
If one stops the rear tire with the rear brake while its in the air, does that loss of gyroscope effect decrease safety of the stoppie? I don't know myself, I never put the rear tire more than a couple inches in the air.
Lastly, you are right that the BMW's situation with virtually-no-brakes-when-engine-isn't-running isn't inherent to ABS per se, but it is inherent to BMW's system because their ABS system is built around it being a power-assisted system. The brakes wouldn't be power-assisted if not for the ABS, and BMW failed to make them so they would work decently without the power assist.
Does it ever matter?
Well, sometimes you're maneuvering the bike on foot and by hand without the engine running. One journalist already wrecked a BMW this way.. it was on a grade and he had not been warned there were essentially no brakes without the motor running, so it caught him totally by surprise when he reached for the front brake and could not stop the bike from rolling down hill out of control. Secondly, of course one could have an engine failure while riding. I'd suppose that if one stayed in gear and kept the clutch out the brakes would keep working though. I don't think it's a huge issue, but it seems a needless one... plenty of cars with power brakes have adequate brakes without the engine running so I can't imagine why that should have been impossible for BMW.
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frEEk
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ummm... yeah
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posted October 04, 2005 10:04 AM
you really can't answer this question without knowing exactly how the ABS system works (ie. their algorithm for when to engage). i basically echo trenace's answer, in that it probabyl depends on whether the brakes are linked. either way, i would suspect that taking a rolling stoppie right to a full stop would likely be next to impossible, as you would have to get both teh front and back wheels to stop and the same time to avoid triggering the lockup sequence.
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ninja12
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posted October 04, 2005 12:26 PM
"So if your rear wheel is still spinning 100 mph, ABS probably would not allow a stoppie to any speed below for example 80 mph, I would think. "
So you are saying the the ABS would assume the 80mph front was slidding when compared to the 100mph rear.
If that's true what would happen if you were on a 80mph wheelie and touch the brakes?
Would it think the 5 mph front was slidding? What would it do to the rear?
just for thought
Watch out, here comes traction control .
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trenace
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posted October 04, 2005 12:36 PM
Yes, I believe that's correct, if the computer does not know the rear is in the air and is not programmed to account for that, if it detects one wheel spinning much faster than the other while on the brakes, it assumes the slower wheel is sliding.
Never thought about the wheelie question and the speed difference there. I guess it would think the front was sliding, unless it has logic to disregard the front wheel sensor when no front brake is being applied. One would hope that even if it "thought" that, it would see no need to interfere with the rear brake, there being no evidence of the rear sliding.
A bike with anti-rear-spin traction control I think could decide the rear was spinning when instead the front was wheelying, if it didn't have logic to detect the full fork extension and permit the speed difference in that case.
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238mph
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posted October 04, 2005 06:38 PM
Too much BS.... pretty soon we won't need to know how to ride either....
I can remember how insulted I was when the 900cc Z-1 came out with an electric starter
Any bozo could climb onboard and hit the button... (women...)
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ZXLNT
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posted October 05, 2005 12:49 AM
Lol funny but true..
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tuusinii
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posted October 05, 2005 01:10 AM
Edited By: tuusinii on 5 Oct 2005 02:23
In stoppie I meant that at the very end when the rear lifts the tyre isin't sliding but it is rolling slower than it should (so the rear would be in ground). At that time the fork (and the rest of the bike) is rolling around the front axle so relatively to the front wheel the abs sensor sees the tyre is locked so it takes some pressure away.
Of course all this have much to do how the ABS is programmed to work. And one thing about the ABS. It dosen't work so that it compares the front and back wheel speeds but it is monitoring both wheels simultanously. When the tire is close to locking it has very fast acceleration (deacceleration). The ABS ECU notices this and then takes some pressure of because it nows it's not possible to the bike (or car) to stop that fast. So then the wheel starts to acclerate again and the ABS then gives back more pressure. ABS does this so fast that the wheel won't lock up but is very close to that. Ideally the tire is in fact sliding 1-10%. (At least on a car for maximum braking). Then there are the limitations how fast the system can work and how close to the locking the tire can be left to go. Because even if the stopping is faster when the tire is sliding a little it makes steering harder so it's a compromise.
And in cars the power brake (usually) works for couple of brake times even after the engine has been shut down because it works with airpressure (well in fact a lack of it). So the pressure stays there for a while if the brakes aren't occopied.
About the original question. You could theoritically do a stoppie but I doubt any of the real systems are made so that You can do it - at least not very high.
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trenace
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posted October 05, 2005 05:22 AM
Really? You have it for a fact that given ABS systems do not utilize both accelerations AND the speed of each wheel, taking the higher speed wheel as evidence of what the road speed still is?
My understanding is you're mistaken -- ABS systems generally use the higher wheel speed and particularly reference point of recently or presently known speed of an unbraked wheel (as is the case of the rear wheel in a stoppie) for their principal determination of road speed: not accelerometers, GPS etc. Deceleration rate of each wheel is also part of the picture but not the entire picture.
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ninja12
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posted October 05, 2005 08:04 AM
Anti lock or traction control.
Why would anti lock release pressure on the front because it thinks rear is sliding.
Should it not release the rear? In which case it would have no effect on the stoppie
other than the gyro effect.
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fish_antlers
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posted October 05, 2005 08:11 AM
what a can of worms!! guess someone's gonna have to get their hands on a 14 and try 
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k bryant
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posted October 05, 2005 09:26 AM
You started it! 
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fish_antlers
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posted October 05, 2005 09:56 AM
nope.. it wasn't me
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D
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posted October 05, 2005 10:13 AM
quote:
what a can of worms!! guess someone's gonna have to get their hands on a 14 and try
Fer sure - way too many variables present in order to try and answer that question.
One thing to remember about most ABS is that most of them are programmed not to engage below a certain speed (usually in the 25-35 mph range, BUT maybe the bike application will be different).
And of course as mentioned earlier in this post - if there is ABS then traction control can't be too far behind (basically reverse ABS if ya think about it).
Some differences here (versus cars) is that bikes will need an angle sensor to calibrate for activation of said systems - if that comes into play (or already is) then whichever system it is may well prevent a stoppie/wheelie.
Does the 14 ABS rely on wheel speed only or is there and anti-dive portion built in to the ABS as well?
Is the rear also ABS/linked or independent?
Just too many variables and not enough info.
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zxfingyz
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posted October 10, 2005 07:38 AM
So the 14 comes with ABS as an option or standard?
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D
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posted October 10, 2005 10:04 AM
Optional (I believe).
At least it had better be.
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CrotchRocket
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posted October 10, 2005 04:16 PM
You can stoppie a Honda XX with Linked Brake System!!!
I think we have a new Vince Hill
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Jason Miller StreetBike Seminars
*****DragRacers do it better, because they dont cut Corners*****
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Hannula
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posted December 12, 2006 03:11 AM
The thread has cooled down but with no conclusive answer. Here it is (drum fill...): the 14 ABS can do a stoppie, a low one at least. Haven't tried high ones for obvious reasons.
Second, my previous bike, a VFR with linked ABS, could stoppie low ones as well.
Myth...BUSTED!!
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