There is no reason to ride a bike with ABS any different than a bike with out ABS. All ABS does is keeps the wheels from locking up. Once the wheels are locked, you are not in control, and are a long for the ride.

Search on youtube about ABS, there are lots of videos showing how the system really works.

 

I wanted ABS on my bike but they didn't have one with it. And there's no telling what they'd cost to install...even if they could.

 

It does not take "longer to stop with ABS". ABS is not the brakes. ABS is a system that prevents the brakes from locking the the wheels.

The same motorcycle will take longer to stop with ABS activated, than it would with proper threshold braking. However, only a rider with excellent braking skills achieves that. Look at this video:


This is on a very good surface, under controlled conditions, and compares properly executed threshold braking with the total reliance on ABS (jerking the front brake lever, and stomping the rear brake pedal). The motors are identical, and both are ABS equipped. From 40 MPH I stop in 48 feet using threshold braking, while the other rider stops in 71 feet.

The vast majority of riders cannot get stopped in 71 feet from 40 MPH so, for them, even inappropriate use of the ABS system is better than what they have now.

However, with very little practice, a rider can improve braking skills to out-perform total reliance on ABS (the far motor in the video). More importantly had the other rider in the video attempted to brake properly, then over-braked resulting in ABS activation, the stopping distances would have been much closer. With the far motor's stopping distance only 5 to 7 feet longer.

The proper use of ABS is to correct for errors, not as the primary means of stopping. Every time a rider has ABS activate, he should be asking himself "what did I do wrong?". The likely answers are either poor braking technique (improper application) or poor surface appraisal. The great thing is that, with ABS, those questions can be asked in comfort. Without ABS, the same circumstance would have led to a skid, and likely a crash.

Again, if anyone is interested in more information on ABS, please email for my booklet at:

motorlessons@hotmail.com

Harris
Denver, CO

www.youtube.com/conedown

 

What you describe here is actually a pitfall of ABS. In this scenario once the wheel hits the paint and the ABS detects a potential lock up the brakes are virtually released so the wheel won't lock up on the paint. That's great, but once the wheel has moved 6" you want it back on will full braking power. That doesn't happen, the bike will continue for some distance with NO brake what so ever. A very dangerous situation.

So consider the exact same scenario without ABS. You're full on the brakes almost skidding the wheel on the dry pavement. You hit the paint the wheel locks and you skid for 6", then you hit the pavement again and you can once again work the brake for full effect.

Nothing scarier than when you hit the brake, especially the rear, the wheel hops on a bump or rattles over a train track and you feel the brake pedal rise under your foot releasing the brake to an unchecked roll. This is common and people should be educated to handle such events.

 

what should we do when this happens?

 

I'm more worried about the front locking up, relying the rear brake for stopping is dangerous.

 

What you're interpreting as "pitfalls of ABS" are actually indications of two things: one is a lack of understanding of how ABS works, and two is human nature.

To understand the concerns you mention, one must accept the fact that if ABS activates a locked wheel skid would have occured on a machine not equipped without ABS (for the super-tech people, there is a theoretical band where this would not be true, but it can be ignored in the real world).

So, if we accept the above, lets look at the change in surface affecting front braking. Lets assume the motor is traveling 40 MPH, which is 66 feet per second (fps). If the painted line causes a lock-up, on a non-ABS machine, the only way to stop the skid, and resume braking is for hte rider to properly execute the response to a front wheel lock-up. that is to Release immediately and reapply properly. Considering human percetion and reaction time, the best possible interval for this to occur is 1 second, and likely more; and that is just to get braking re-initiated. The H-D ABS system samples at a little over 6 times per second. ABS effectively performs the Release Immediately and Reapply Properly sequence 6 times a second. Thus a rider skilled enough to recognize the front wheel lock-up, and then react to it perfectly will lose at least 66 feet of braking distance. A rider on an ABS equipped machine, who simply pulls the lever and keeps it pulled, would lose just over 10 feet. Of course better to be the rider that has perfect surface appraisal skills, who loses no braking distance, but since our emergency stops don't occur in ideal pavement conditions, I'd rather have the ABS handling my front lock-up than having to do it theold fashioned way. Mind you inthe days before ABS equipped motors, we'd seem to have one wreck during threashold braking training in an operator school. That's a rider with training, and practice, under a controlled condition, who still failed to recognize the front wheel lock-up. When you change the circmstance to a rider confronted with an unexpected hazard, on an unfamiliar surface, and without warning, and the odds end up stacked against him in a hurry.

Your theory that the wheel would skid for six feet, and then begin rolling again upon encountering the improved surface, is in error. Once the front wheel has locked, even if the surface improves, it will not begin rolling again. The braking pressure muse be released, and then re-applied. \

As for the rear brake over rough surface scenario, again ABS is doing exactly whatit is designed to do - keep the wheel from locking. What happens is again the rider is not appraising the surface correctly. The bumps are enough to completely unweight the rear end of the motor. ABS senses this,and only allows enough braking power to not lock the wheel. If the wheel is off the surface, or nearly so, this amount of braking power is none. More likely the surface is so poor the amount is very low, and the rider's perception is that the barkes are doing nothing. Typically this occurs at speeds down in the 10 MPH range,and all of us who began riding in the pre-ABS days, are familar withthe fact that a moment of rear wheel lock-up in that circumstance is no big deal. We would typically just keep the brake pedal under pressure, and perhaps modulate it a bit. Alas, the 1/6 of a second that ABS uses, at 10 MPH ia about 4 feet, and often the surface doesn't improve in that distance, so it can be very disconcerting. This is human nature,and I'll be the first to admit that in the times I've had it occur, I can simultaneoulsy know exactly what's happening, and still have it in my mind that the brakes have failed.

You mention the pedal coming up under your foot indicating the brakes "released" actually that is the pulse built into the system, designed to alert the operator that ABS has activated. It is not actually the "release" of braking. H-D decided to go with a particularly strong feedback pulse, but the rider should continue to apply pressure.

That feedback pulse is a reason I feel it's very important for a rider to deliberately engage ABS under a controlled situation, to know what it feels like. It's not uncommon for a rider, or the driver of a car, to release pressure on the braakes, because the feedback pulse feels like somehting is wrong. In fact it's doing exactly what it's supposed to - telling the operator that ABS has cactivated.

Harris
Denver, CO

www.youtube.com/conedown

 

Well, I disagree about the 6 times a second. Also I have never activated the ABS on the front, I was only presuming it worked as the rear does.

But many times I've been in situations where the rear wheel momentarily locks up. The best example is when crossing a train track at 90 degrees. If you also happen to be slowing down using normal braking power, the wheel rattles over the tracks and your foot is pressed up from the ABS actuating, releasing (yes releasing) the brake and you continue on with no rear brake. Luckily the front didn't behave in this mannor or I would have no brakes at all.

So the solution is to manually release the brake when you approach an area where the wheel might hop then reapply. Problem is, you don't know where it's going to happen for sure, and most of the time when you're on the brakes it's because you need them NOW. Otherwise I'd anticipate and gear down let the engine slow me accordingly.

You don't know me, or my experience level, but believe me I have plenty of experience. I've been riding my entire life and not just pleasure riding but competing, and at one point in my racing career at the professional level.

This is a pitfall to ABS.

 

Finally! A thread that concerns something that could truly save your life. If I ever move down to a bagger, it will have ABS.

 

Negatory on the release and reapply. You're not understanding the situation that I described.

Let me say a different way. Lets assume you are applying the brake at 50%, and slowing at a controlled and reasonable rate of deceleration. Far from any skidding situation. Then the wheel rolls over something really slippery, like a wet piece of shiny train track. With NON ABS, the wheel will stop due to the 50% brake application, the when it his traction again will continue to roll again with the brake maintained as before. You might here a little squawk as it momentarily skids hitting the dry pavement.
With ABS, that millisecond when it would have locked up will result in a release of the brake. You will have no brakes. You say it re-evaluates 6 times a second, in my experience it seemed a lot longer than that. Even so that is 1/6 of a second running with no brakes, and if you're on a downhill it's 1/6 of a second accelerating due to gravity.

That sir, is a pitfall.