Braking by Nick Ienatsch

I am not sure the numbers but someone who designs roads could give you the traction co-efficient for a given turn, all factors being equal. But the final outcome based on his numbers will be generic and may or may not work well for a bike since they do the numbers based on auto's etc.

Here's a dumb question.

First, a preface: I consider myself a very techno-friendly rider. Meaning, I'm not at all averse to whatever 21st century gizmo can be added to the bike to make it easier or safer to ride. No, I don't want the stuff legislated, and no, I don't want it on every bike. But I like having a marketplace that supports making all the nifty gizmos and doo-dads available to the riders that want them.

With that out of the way... I can't recall any training course / motorcycle expert / experienced rider tell me anything different from "always brake progressively." Holding a baby bird, cradling an eggshell, counting "one-one thousand"-- whatever you call it, everyone says the same thing: don't grab or slam on the brakes or else bad things can happen.

Now, maybe there are instances you need to grab or slam the brakes as hard as you can (on dirt, maybe? I don't ride dirt, I wouldn't know). But on the street?

So... where are all the electronic-assisted brake options out there? It seems to me that wiring the front and/or rear brakes on a street bike with a system that resists grabbing/slamming and progressively engages the brakes no matter how hard you yank on them would avoid go a long way to avoiding this problem, no?

Alright, what's wrong with this option? Fire away...

Bikes are two wheels not four, and those systems are available, they are called anti-lock brakes but they only work well in a maximum braking straight line situtation and we are talking about braking in a corner here.

awesome read, a reason why I hate linked braking but love abs

Really?? Hadn't noticed.

Sorry, I either mistyped or you misread (I'll charitably assume the former!).

ABS indeed works best in a straight line situation, but to my knowledge, works only when traction is lost, i.e. ABS kicks in the moment a wheel locks to release and re-brake.

It seems to me, however, that there may be benefit to a system that engages the brakes progressively BEFORE wheel lock is achieved and ABS would be required. Perhaps (some) bike ABS systems do this already; I'm unaware of the technical differences between the various ABS systems out there.

Again, if the ideal is to brake progressively to avoid locking and losing traction-- yes, even in cornering, thank you very much-- why not have an electronic system that addresses this problem before it becomes a problem, versus after?

Since we now have electronic traction control which helps control wheelspin in a corner, I'm sure ABS which works in a curve will come along before too long. The drawback of these systems is that once they become commonplace people will loose the ability to ride without them and will no longer even understand the dynamics of the bikes they are riding. Just look at all the cage drivers out there unable to drive with a manual transmission, and absolutely clueless on the dynamics of driving.

Of course, plenty of riders don't really understand what they are doing so more electronic safety devices may just save their asses.

For the guy wondering about measuring traction changes as conditions change.

Go straight, pull in clutch, apply back brake until tire locks, unlock wheel get a feel for how much pressure it takes to do this.

Wait for conditions to change, repeat above.

I do that whenever I wonder what the actual traction of the road is. You do it enough you'll develop allot of confidence in shitty conditions.

Yes it's a sad world, Even in cars people have forgoten how to use brakes, now days its mash the pedal and thats it. Its sad for many reasons, we had to learn to use the brakes properly and having brakes that you could lock up helped in bad winter driving conditions when you could not make the hill and locked it up going backwards to allow you to flip ends and then get back down the hill.

Your understand of ABS is flawed, a good system detects that the wheel is slowing down faster than it can possibly slow down, and should start to release pressure before the wheel is actually locked.

This is why with training a good person can outbrake ABS by a bit because the person can keep it right on the threshold of maxium braking about 5-10% slip depending on tires, meaning the braking tires are turning 5-10% slower than actual speed over ground, versus abs going from below maxium braking and 0% slip back to 15% slip and repeating.

Why do you think current ABS doesn't work in a curve?

Go take an ABS equipped bike and grab a handfull of brake while leaned way over. Then let us know how it worked out. Make sure you are wearing all your safety gear and there is no guardrail.

Already done. Except that there was a guardrail. It worked out just fine.

My point was that a lot of people say ABS won't work in a curve. I've never heard anyone say that it didn't work in a curve. And yes, I realize that there are several reasons that could be the case. :)

Thanks for the response.

Yeah, I know there's the "this dumbs things down too much" factor in play-- comes out in EVERY thread here-- but not every rider out there is an expert on this stuff, and let's acknowledge that even the experts often appreciate the assist/margin of safety that tech can provide.

Besides, don't like the tech? Don't buy it. Or, buy more bikes, so you can choose which one you want to ride that day- the tech-enabled machine, or the pure classic experience. I'm a fan of the latter school

Your hatred is misplaced. I have two bikes with linked, ABS brakes and both work beautifully. You don't have to think about the fact they're linked or ABS equipped, you just use the brakes and you stop.

Everything I have read says that ABS is not designed to work in a curve. I never put it to the test on my R1100GS. The newer systems are more sensitive than the older ones. I guess it all depends on how far you are leaned over and how much brake you use. I'm sure it works just fine at a mild lean angle but if you're way over I wouldn't depend on it, especially on an older bike.

Yup, I've read a lot of that too. I've also read that you can't use regular brakes in a curve. I've never read that anyone actually tried to activate ABS in a curve intentionally. Something about how ABS bikes are always too new and expensive to risk scratching up.

I was on a '95 1100GS. But I don't know that the newer systems are necessarily better. I don't have an ABS bike any more, so couldn't experiment myself.

Were you leaned way over, or just a little bit? I regularly used my brakes in curves on my 95 R1100GS but in 87000 miles, I never had the ABS activate in a curve, and I never crashed except for an encounter with Bambi. Of course, I never tried to use the brakes hard while leaned way over.

As for using regular brakes in a curve, trail braking has been a common and well know technique for a long time even if there are some who say not to do it.

How would it know?

I'm not great at physics and this may be totally wrong, but my understanding of ABS & curves is as follows:

The ABS system is measuring wheel rotation in line with the bike. That is, no lateral component of motion or force comes into play in ABS calculations, strictly wheel rotation in comparison with speed.

In a curve, if you hit your brakes, you are unlikely to be able to slow the tire quickly enough to engage ABS without lowsiding.

You have extreme lateral forces when cornering that are NOT taken into account by ABS. Any lateral sliding beyond the traction of the tires obviously can't be compensated for by the ABS.

If, in some impossible situation, in-line traction loss could occur due to hard braking while cornering without lateral traction loss, ABS would kick in just fine.

But I think that's an impossibility at anything but shallower lean angles. I couldn't begin to calculate the thresholds, but at any reasonable lean, lateral traction loss will occur far sooner than in-line traction loss when braking hard.