|Topic Review (Newest First)|
|06-22-2010 07:46 PM|
Originally Posted by AJCruzin View Post
(one should also read up on "Trail Braking")
There is a decreasing radius turn I run through here alot that does require me to brake while leaned over. The problem with falling really has to do with overbraking or locking a wheel.
And admitedly I may be confused myself as to the result of not using the rear brake and locking the front wheel in a turn.. mostly because I have never done so and lack that bit of first hand knowledge...
|06-22-2010 12:32 PM|
When leaned over in a turn, it is possible to use your brakes, but you have to remember that you only have a certain amount of braking traction available, since a lot of your available traction is being used to corner. Several of the better MC books cover this in great detail. Here is the diagram used to demonstarte the concept:
|06-22-2010 01:36 AM|
At least that's how it looked to me...he could have hit a patch of gravel or tried to counter-steer the wrong way...or ran into a bat. I did not get to interview him after the crash to ask what he did.
The laws of physics seem to say you are more likely to high side locking the front wheel than the rear...(But as you say, letting go of the rear brake can cause a high side)
Also keep in mind a good rider knows how to avoid a highside....like turning the wheel as hard as you can into the inside of the turn ....much like what it looks like the fellow on the red bike did. He felt the rear give out and rather than risk a high side he rode the bike into the ground by turning the wheel hard to the left.
But hey I could be wrong, perhaps someone knows him and can ask him what he did.....
|06-22-2010 01:04 AM|
|06-22-2010 12:15 AM|
Originally Posted by Knifemaker View Post
Watch the red one. He touches his front brake in the turn and low sides. http://www.youtube.com/watch?v=WNrp1Jzs7pg - Leaning left, falling left (low).
This other guy locks his rear brake and then lets go of it while leaning over on good pavement and high sides. http://www.youtube.com/watch?v=hR5GGmwbmNI - rider goes airborne, (high).
This next guy high sides and he doesn't even use his rear brake. He just loses traction and then backs off the throttle trying to save it. http://www.youtube.com/watch?v=rlMbFlPzS24 Engine braking is still braking and anti-lock brakes still wouldn't have saved him.
The danger with the high-side accident isn't locking the rear wheel, it's letting go of the rear brake on good pavement. As the Skidding / sliding rear wheel starts to spin again and gain traction it wants to snap back in line behind the front wheel's track. This snap causes the bike to throw you off the high side.
This isn't as scary for an experienced rider on a lose surface like gravel or sand since traction will be reduced and the snap won't be as violent. However many novice riders who accidentally lock their rear wheels hear the tire screech and instinctively let go and high-side as a result. Larger picture point being: Don’t brake in turns and if you accidentally lock the rear wheel when stopping in a straight line it’s safer to just keep it locked until you stop.
Originally Posted by Knifemaker View Post
|06-21-2010 08:47 PM|
Locking the rear will usually cause a low side , but as you mentioned, if the rear end has already lost traction and has broken loose, and you let go of the rear brake, real good chance it will highside.
You have to keep in mind there is a difference between skidding and sliding. The rear end can "slide" but the wheel is still turning and has forward traction. If the the wheel stops turning, or looses traction so it is no longer driving the bike forward, then it is a skid.
Modern ABS systems react in 1/10,000ths of a secound, Older ABS might have left "dashes" but the ones on bikes now release the wheel long before rubber gets laid.
"If you lock up your wheels while leaning in a turn you will fall down before the anti-lock brakes detect the skid and start working"
You may not have "locked" the wheel, because you can fall down because you simply over braked...not because the wheel ever locks up. If your going 35 mph through a turn and you slow the wheel down so it is only turning at 30 mph you can loose traction , low side or high side with out the wheel actually being "locked"...(not turning) ABS will not kick in because the bike itself has slowed down, which will still make you fall , or because the wheel has not locked up.
The point here is if you brake hard enough to even get close to "locking the wheel(s)" while leaned over in a turn, you are going to eat asphalt, but it not because the ABS did not have time to react, it is because you have upset the balance of the two forces working on the bike.(See my other post) and have sealed your fate..the bike will begin to fall or flip nano seconds before the wheel actually stops spinning, and that is why the ABS would be useless in a turn.
New ABS systems also can compare wheel speed of front and rear wheels to make sure they are the same when braking, and the same sensors are used in traction controll systems to make sure when you grab some throttle going through a turn you don't break the rear tire loose by opening it up too much (a possible problem with mega horsepower bikes) or to keep you in controll if you are " accelerating abruptly while swerving"...
|06-21-2010 06:14 PM|
Locking the front wheel = low side kind of accident. You will basically fall down towards the side you were leaning towards.
Locking the rear wheel and letting go of it on a good surface = high side kind of accident. The bike violently throws you off in the opposite direction that it was initially leaning.
Anti-lock brakes work to keep the wheel spinning once it's locked up. If you lock up your wheels while leaning in a turn you will fall down before the anti-lock brakes detect the skid and start working. Ever see a kid mark from a car that used its anti-lock brakes? The skid marks look like dashes not like a solid line. That was the anti-lock system pumping the brakes very quickly… after they were locked up.
Hard braking while leaning is generally a bad idea. That's why the MSF teaches the technique for doing quick-stops in turns as Straighten, Square and Stop -in a straight line because that's when you have the most traction for stopping. Of course if that's not an option for you due to circumstances (the possibility of going over a cliff for example) then trying to brake and straighten up the bike simultaneously to stop becomes more preferable than going over the cliff. You'd have to weigh your options with that one.
Braking while swerving is very bad for your health. So is accelerating abruptly while swerving. You want to maintain steady throttle to keep your tires within their limits of traction.
ATGATT, I'd rather sweat then bleed any day.
|06-21-2010 05:31 PM|
Read the summary of the Hurt Report on motorcycling accidents. Read it again, and think of how each point applies to YOU, and what will you do about it. Then choose your gear and riding tactics to best keep you safe. Not to look cool, or fit in. This is for YOUR LIFE (and skin).
It takes some personal strength to ride smart. You have to ignore the legions of T-shirted types making jokes about your high-viz armor. You have to put up with being hot while stopped in traffic. It's worth it. The ATGATT riders I know who have crashed have all (so far!) walked away with bruises. The non-geared tend to get skin grafts, therapy, and months out of work.
I'll be riding home ATGATT today and it's 95 degrees. I'll sweat a lot when I'm stopped in traffic, look weird in the bright yellow jacket, and I LOVE IT. The Endless Belt Sander is running under my cycle, and I'm not risking bare skin.
|06-19-2010 03:12 PM|
KM-I deleted the reply but since you replied I will put it back up...lol...
My bad experience came with my first ABS equipped 4 wheele Dr. PU pulling a boat & trailer, bet you can guess what it was, and you can pull the steering wheel off but they don't do anyharder breaking...lol...
I'm not knocking ABS by no means, but experience and a cool head w/skilled hand and foot is hard to beat...
Same with auto, but panic will get the lid closed on you, that is where ABS can and does save unnessary diggin...
But it is also like a lot of other safety devises, we get to depending on them, ie outboard neutral switches, mower kill switches, KICK STAND KILL SWITCHES...lol...
Just my thoughts on the subject, others will differ...
Have a good one...Old Dog...
|06-19-2010 03:03 PM|
Originally Posted by Old Dog View Post
ABS , and the new technology of "traction controll" on motorcycles is a real good thing. Perhaps the best thing ever that has been added to a motorbike.
A "cool head" is very hard to find when an 18 wheeler is baring down on you, no matter how skilled or experianced you are.
Tests on dry clean roads do show a "skilled rider" on a non ABS equiped bike can outbreak a newbie on an ABS model easily. The real mind-fk is that same "newbie" on the ABS bike out braked the "skilled" rider as soon as the road surface was altered, either by sand, water, or gravel. In one instance the new rider with ABS stopped 30 feet sooner than the experianced racer on a wet course, when starting at 60 mph.
So as a "safety feature" is really hard to argue against, and may be more significant in rider protection than a helmet....
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