2004 1150RT - Stupid rider, ABS, ???

[autobahnracing28]

Hello to everyone on this site. I have been lurking for some time now and after an incident last weekend thought I would join the discussion.

 

Background - I am a long time rider, various Japanese bikes, with a history of road course racing and some motocross. I am new to BMW cruisers and ABS braking. I purchased this bike about a year ago so my wife could ride comfortably with me and we have enjoyed some nice rides.

 

Last weekend we were coming over the top of a hill, looking into the setting sun, into a downhill, posted 15 mph, left-hand corner. As I let off the throttle to downshift and brake the rear tire momentarily locked up before I pulled the clutch in. As I transitioned to braking I had virtually nothing except, I assume, a whirring sound from the ABS. We went off at mid-corner, about 25-30 mph, and I was able to keep it on the wheels as we went down a bank into a field and then back up onto the road.

 

Further investigation revealed that we had encountered a diesel fuel spill that I was unable to see due to looking into the setting sun. Supposition and observation of subsequent corners suggest that a big-rig we had met just prior to the incident had probably left his fuel cap off and was sloshing fuel out as he went around corners.

 

My riding experience tells me that I should have been able, even with the slick condition, to brake and slow enough to negotiate the corner. I feel as though the ABS caused a dangerous situation to become far worse.

 

I would welcome all thoughts and certainly don't mind any criticism.

 

Randy

[lawnchairboy]

I'm sure you won't find a shortage of opinions on this.

 

[cali_beemer]

I'm lost on what actually happened...were you leaned into a turn, slam on the brakes and the ABS kicked in?

[autobahnracing28]

I'm lost on what actually happened...were you leaned into a turn, slam on the brakes and the ABS kicked in?

 

It all happened before I had a chance to lean into the corner...bike was straght up.

[tallman]

"left-hand corner. As I let off the throttle to downshift and brake the rear tire momentarily locked up before I pulled the clutch in. As I transitioned to braking "

 

I read this to mean;

 

bike upright

you had downshifted/ applied brakes/ not pulled in clutch

 

the rear wheel locked

only the rear wheel

 

on a 2004 R 1150 RT

w/pillion

?

[philbytx]

Not a brake issue. A Sh&* happens issue.....

[Quinn]

I'm understanding that you eased off the throttle, applied brakes. ABS kicked in but caused no change in forward speed and you rode it straight off the road where I assumed the brakes were able to stop you?

 

And your question is what would have happened differently without ABS?

 

------

 

 

[autobahnracing28]

I'm understanding that you eased off the throttle, applied brakes. ABS kicked in but caused no change in forward speed and you rode it straight off the road where I assumed the brakes were able to stop you?

 

And your question is what would have happened differently without ABS?

 

------

 

 

Substantially correct restatement. Initial rear wheel lockup was due to release of throttle just after cresting the hill. After immediately pulling in the clutch and braking there was no further lockup and no noticeable braking either. It all started several hundred feet before I got to the corner. Initial speed over the hill was about 45 mph.

 

Yes, that is a question. I think I would have been able to slow enough to negotiate the corner or even come to a complete straight ahead stop w/o ABS.

[autobahnracing28]

"left-hand corner. As I let off the throttle to downshift and brake the rear tire momentarily locked up before I pulled the clutch in. As I transitioned to braking "

 

I read this to mean;

 

bike upright

you had downshifted/ applied brakes/ not pulled in clutch

 

the rear wheel locked

only the rear wheel

 

on a 2004 R 1150 RT

w/pillion

?

 

Not exactly correct...I did not get to the downshift until I was off-roading. I released the throttle, then pulled in the clutch and braked. Yes, only the rear wheel locked.

[lkraus]

It sounds like the fuel spill simply created a situation where there was no traction, and you did not see it due to the sun and your approach speed. A curve posted at 15mph is pretty tight. I tend to automatically add 10 to 20 to the "suggested" curve speeds when they are in the 30 to 50 mph range, but if suggestion is down to 10-15 I tend to heed the road engineers advice. Doubling the speed in a 15 with a passenger is probably pushing your luck without perfect conditions, which you did not have.

 

It sounds like you never began the turn. With diesel on your tires it is probably just as well.

 

If the ABS kicked in, it was because the tires had insufficient traction to handle the amount of braking you were trying to apply. On a non-ABS bike it is probable the wheel(s) would have locked up - motorcycles with non-spinning wheels tend to fall over quickly, steer poorly and throw you off when they regain traction.

 

I'm not familiar with the 2004 RT ABS, but I had an older truck that seemed to lose all braking ability once the ABS kicked in. Getting off the brake entirely to deactivate the ABS, then reapplying with less pressure at least gave me the illusion that I was more in control, but I'm doubt it really helped my stopping distances.

 

Basically, it sounds like you were just traveling too fast to see and prepare for the road conditions. I can recognize the situation because I've been there and survived to tell the tale. I think we all have at one time or another.

 

Larry

 

[autobahnracing28]

It seems that the ABS is only good for ideal situations where traction has not been compromised and it exacerbates problems in situations with less than ideal traction. If so, of what use is ABS? I don't need any help under ideal conditions and I certainly don't need any negative help in less than ideal conditions.

 

On my non-ABS bikes I would, and did attempt to on this one, have immediately taken the rear brake to pending lock-up and feathered in as much front brake as possible.

 

Some questions I have are:

 

- What could or should I have done differently?

- Did the rear wheel lockup on deceleration in some way activate the ABS? (I was able to clutch and momentarily release the lockup prior to brake application)

- What is the relationship between the ABS and the front and rear brakes? It seemed that I had zero braking power in either front or rear even though I was standing on the rear brake and just attempting to feather the front.

- I there a way to shut off the ABS and still have good brake function?

[lkraus]

I'm a slow typist so there were several new posts and more information while I was preparing my last reply.

 

I'm not clear on a few points. Rear wheel lockup on deceleration (not braking) at 45mph tends to indicate you were already into the diesel? The ABS should not have been activated at all if you were not on the brakes.

 

With "several hundred feet" before the corner I agree you should have been able to stop, unless the entire road was covered in diesel. In that case you would have been screwed on any bike.

 

I don't think I would have been "feathering" the front brake unless I already felt a loss of front end traction. On my '06 RT (different ABS) my response would have been to hit the front brake as hard as possible and rely on the linked ABS to apply the rear brake as needed, knowing my ABS will treat each wheel independently. I understand the 2004 brakes are different. We may need some '04 riders to chime in here.

 

Larry

[autobahnracing28]

Thanks Larry

 

Yes I was in the diesel as soon as I crested the hill. It was a significant and still wet spill but did not completely cover the road. It was a rough/chip seal asphalt surface with what seemed to be enough traction to slow even with the spill.

 

You are probably correct. I should have nailed the front brake also but years of riding non-ABS has tuned my reactions to do the opposite. Although I did not know exactly what I was in, I did know I locked up due to something slippery rather than speed or some other reason so my reaction was to feather the front.

 

"linked front and rear" I really need more information on this bike. I bought it used and it did not come with any kind of manual and no BMW bike dealer within 300 miles of here. There are a number of things about this bike I wish I knew more about.

 

Randy

[Quinn]

I've got an '04RT with linked brakes. Since I can't do anything about that, I just have faith that they know what they're doing. You applied rear brake action by chopping the throttle and that didn't seem to change anything. The ABS system never found enough traction to give you any braking either. Only thing it probably did for you was keep you from high siding when you got back to having traction; without ABS you would have a locked up rear wheel when you hit a patch of traction.

 

All this is guessing on my part. Only times I've actuated the ABS in an emergency has been on good pavement and it kept me upright and pointed correctly.

 

----

 

 

[lkraus]

"linked front and rear" I really need more information on this bike. I bought it used and it did not come with any kind of manual and no BMW bike dealer within 300 miles of here. There are a number of things about this bike I wish I knew more about.

 

Randy

 

Most, if not all, of what you need to know you can find here on this forum using the advanced search function. Check one or more threads completely. Sometimes misinformation gets posted, but eventually it gets straightened out, so you really need to read the whole thread. One of many threads on your linked brakes is at this link.

 

ABS or not, for any bike the vast majority of your stopping power is in the front brake.

 

On your RT, the brakes are linked so that using either the hand lever or the foot pedal applies some brake pressure to both wheels. This happens regardless of whether conditions require activation of the ABS. Squeeze the lever and you get mostly front brake and some rear brake. Press the pedal and you get mostly rear brake and some front brake. The only disadvantage to this system that I am aware of can occur when riding on loose gravel or dirt. Applying the rear brake incautiously can cause the front to lock up or wash out. Or so I've been told, experiment carefully. Newer (2005-present) models have separated the rear pedal from the front brake, though the front lever does operate the rear brake.

 

As far the ABS is concerned, you might want to try practicing hard stops in a parking lot somewhere. Start with low speeds and increasingly hard stops until you know what to expect when the ABS kicks in. That type of practice is what makes me confident that I can get my best possible stopping power with just the front brake.

 

Larry

[Danny caddyshack Noonan]

You did everything right other than predicting the diesel. The ABS maybe avoided a lockup. The give away that something is seriously wrong is when it feels like the bike is accelerating instead of slowing. The ABS will apply modulation to prevent the tires from locking. With no traction due to fuel, that effect is no braking. At that point, you're in for the ride....where ever that goes. If the rear was the only brake applied, then you avoided what could have been a high side or tank slapper without proper control. You might have been able to pull that off but, when you release the brake, the tire doesn't want to spin back up like it will on dirt or a dry track.

 

Grabbing the front in a straight line probably could have not been a disaster but, with a little lean, ABS isn't going to help. You'll maybe be on the way down by the time ABS kicks in.

I've seen some curious crashes in fuel because the math sucks. Sort of like putting out a magnesium fire.

[autobahnracing28]

Great advice and information

 

I wish I had something a little smaller and lighter to practice with but good advice.

 

I have felt and suspected the link between the front and rear but it is good to confirm it and have some information on how it is designed to function.

 

The first day I rode the bike I picked it up at a guys house situated at the top of a small mountain with a fairly steep, 6-10%, 1/2 mile long, deep and loose gravel driveway. After scaring the %$## out of myself trying the brakes I used compression the rest of the way down.

 

Now any advice about getting my wife to go riding with me again

 

Randy

[racer7]

There are several issues with bike ABS that are different than for cars- and exist in part because bike systems, especially on BMWs, have primitive designs that are still about a decade behind the best stuff available for cages.

Your older generation system is even worse than the current BMW system which is not in the league of several others...

 

Some of the issues are fundamental to bike physics and hard to overcome. A locked bike tire on low traction surface has so little ability to gain any traction to start rolling that its a real challenge for the software and hardware guys to make stuff capable of dealing with it.

The ridiculously long stopping distance you experienced is created in part by the long delay times and made worse if you don't immediatly reduce braking effort to help a marginal system- the ABS systems can effectively go brain dead if the tire can't get up to speed quickly.

 

I've got an 08RT and its ABS sucks -but not as much as your older model -because its rear is not linked when used alone.

Having 50 years on bikes without ABS including riding in snow in winter, I'd be perfecly happy to always be without them especially if they don't get a lot better on bikes. I've spent a lot of time teaching on tracks in the best cages and there is some truly impressive electronic stuff in some but BMW bikes don't even make mediocre grade for ABS function.

[tallman]

"It seems that the ABS is only good for ideal situations where traction has not been compromised and it exacerbates problems in situations with less than ideal traction. If so, of what use is ABS? I don't need any help under ideal conditions and I certainly don't need any negative help in less than ideal conditions."

 

Still having some understanding problem.

You let up on throttle dumped it down a gear, apparently on diesel, riding blindly into cresting hill with turn into the sun, wheel locked from the downshift (you said above no braking until later) on the diesel?

Then you blame ABS saying you don't need help under ideal conditions.

Most of us don't in an ideal world. That isn't reality.

Those were not ideal conditions.

 

Looking for help after riding into a situtation like that isn't

going to happen.

Sounds like you just got a new to you bike, haven't practiced using the brakes (your trip after buying the bike down the driveway) then rode 2 up into less than ideal situation.

Not sure what your ABS has to do with this particular situation

Why not try them in the rain?

[g_frey]

The only time my ABS activated in 8 years it let me roll right past a stop sign into the middle of a luckily deserted road. Not a fan, I managed fine for 30 years without it. Some times that involved leaving the line I had chosen. Love the rest of the bike.

[Mister Tee]

ABS has limits, and some bike ABS systems are better than others. If you hit ice or oil on the road, all bets are off, as ABS is only effective if you have a chance of regaining traction after momentarily or partially losing it. But, that's an issue with manual braking as well.

 

I never really got a chance to fully test the ABS on my 08 RT, but when it did kick in it was quite abupt and annoying. I'm quite happy with the ABS and traction control on my Concours - and I have tested that out on cold, wet roads.

[nealopp]

I'm going to echo some previous comments: practice, practice, practice.

 

Take the MSF expended rider course. Unless you've taken it before, there's something you will learn.

 

Take it with your RT.

 

Practice panic braking. Find an empty lot. Spool up to about 25 mph, then squeeze front and stomp the rear as much as you can. Get used to the feeling. Do it a couple times.

 

Let the brakes cool down for a while, then try it from 40. And squeeze for all you got!

 

Cheers,

Neal

[BFish]

just ride it normally. the linked brakes/abs will not be an issue after some saddle time.

[Bill_Walker]

There's a phenomenon with R1150 ABS that may have contributed to your issue. The system, for some reason (anti-stoppie control?), if the rear wheel locks and the front doesn't, will reduce brake pressure to BOTH wheels. This is sometimes experienced when hitting a bump while braking down a steep hill. Suddenly, the bike rushes forward as though you've let off the brakes! But in that situation, braking usually comes back quickly. But I'm thinking that this effect may have played a part in your incident.

[autobahnracing28]

Thanks for all the responses. What a great group. I have learned and will continue to learn.

 

I am still not sure if I like ABS but I feel increasingly comfortable having greater knowledge of how it functions.

 

Randy

[tallman]

Randy, if you need it you will be very glad.

Sudden stops when a vehicle/critter/something falls off the truck ahead and nowhere to go.

Throw in rain etc and there are times it is a gift.

As you discovered (maybe) there can be times it takes getting used to.

The BMW rider Jean P who would demo models loved doing stops

through wet course and threw them all around, even LT, like he was on a trials bike.

Good luck.

[cali_beemer]

I put many miles on my 04 RT...from the description, although still a bit uncertain...it sounds like you had as another user reffered to, "an Oh S&%$ moment"...It sounds like the ABS prevent the bike from what could have been a lay down. Anytime ABS engaged on my 04, it was for rightfull reason...If the ABS engaged, it means you didnt have enough traction....any other bike that usually means a lock up...I wouldnt look at this as a ABS is lame, but more as a ABS saved my bacon situation. As another user posted, find an empty parking lot and get familiar with the bike engagaing ABS...I do it with every ABS bike I own (I wont buy a non ABS bike anymore)..it gets you famiiar with its threshhold point and also what the bikes characteristics are under such situation so dont freakout when it happen for real.

[autobahnracing28]

Well I went out and did some testing today. Hard braking from different speeds on pavement, gravel, straight line and cornering. It is supposed to rain this weekend so maybe some careful testing on wet also.

 

I was able to duplicate the freewheeling effect on gravel. With no reservations I will state that I can easily out brake the ABS on gravel and still maintain control.

 

One other thing, maybe not the correct forum, but will throw it out anyway. I wonder if I might have damaged the engine in some way due to the incident I had.

 

I rode the bike about 10 miles home after the incident and it has been parked for a number of days now. Had the bike on the side stand so the left side was the low point. When I went off the road I was still in 4th, holding the clutch in from my initial reaction to locking the rear wheel, after landing about 2 feet down the bank, I downshifted to 2nd, then 1st and drove out of the field. A little bit of a jar as we went off and landed but not enough to unseat us.

 

Never had it happen before but today when I started it up for the first time since the incident all was normal for about 15 seconds then the left side exhaust stated belching smoke. Smoking lasted for about 2 minutes then back to normal. Rode about 70 miles today, several stops with start-ups, and no further indication of a problem.

 

Randy

 

 

[biometrics]

Possibly oil crept into the left cylinder and you burned it off after your initial idle... check your oil level and make sure you aren't overfilled. Just my $0.02 -John

[autobahnracing28]

Thanks, I was wondering about the possibility, that is why I stated how it was parked. I fly old rotarys and they accumulate oil in the lower cylinders.

[George S.]

Silly rider, You will never outbrake ABS!

[tallman]

George,

Being facetious, right?

I'm huge advocate of ABS.

But in some situations non ABS wins.

However, in the majority of cases modern ABS provides shorter stopping distance.

Do a search, this has been bandied about...

I think it was May 2-3 years ago Cycled World did comparo w/professional riders on new Honda ABS system.

In all but one scenarios ABS won, and the one situation where nonABS stopped shorter it was by 1 foot and aqfter several attempts (best I can recall)

 

Older tests going back to early ABS w/a variety of riders the ABS won by huge margins.

 

Again, big advocate but once in a while...

that is based on premise one has practiced threshold braking a bunch and have mastered the skills.

Best wishes.

[George S.]

How can you say I'm facetious when your own example shows ABS wins? Even with professional riders doing the test. With all due respect to the OP, I don't think he's a professional. A ONE FOOT difference in the only example that non-ABS won? ONE FOOT? Are you serious? That's probably within the measuring margin of error anyway.

 

I stand by my comment that in the real world, on public roads and highways the non-professional rider will not be better off without ABS.

[jfremder]

I'm going to echo some previous comments: practice, practice, practice.

 

Take the MSF expended rider course. Unless you've taken it before, there's something you will learn.

 

Take it with your RT.

 

Practice panic braking. Find an empty lot. Spool up to about 25 mph, then squeeze front and stomp the rear as much as you can. Get used to the feeling. Do it a couple times.

 

Let the brakes cool down for a while, then try it from 40. And squeeze for all you got!

 

Cheers,

Neal

 

Yep, practice threshold braking!!! Find a place with sketchy traction and practice some more. Practice two-up. Practice with a washboard road surface. Practice on gravel, downhill. Practice in the rain. Practice on wet grass. The '04 linked system has a few more surprises in store for you, especially on a rough surface with intermittent traction. Activating the rear brake first will help with some of the surprises.

[jfremder]

Well I went out and did some testing today. Hard braking from different speeds on pavement, gravel, straight line and cornering. It is supposed to rain this weekend so maybe some careful testing on wet also. --snip

 

all was normal for about 15 seconds then the left side exhaust stated belching smoke.

 

Randy

 

 

Glad you're getting some braking practice in. You have dual exhaust on your RT?!?!

[tallman]

How can you say I'm facetious when your own example shows ABS wins? Even with professional riders doing the test. With all due respect to the OP, I don't think he's a professional. A ONE FOOT difference in the only example that non-ABS won? ONE FOOT? Are you serious? That's probably within the measuring margin of error anyway.

 

I stand by my comment that in the real world, on public roads and highways the non-professional rider will not be better off without ABS.

 

George,

You said, "always".

Going downhill and encountering rumble strips approaching stop sign ABS can have issues.

There are other exceptions such as this.

So, I would no profess always when asked.

YMMV

Personally I recommend, advocate, and use ABS on my previous and present bike.

Best wishes.

[Quinn]

Am I reading in this responses that the ABS has trouble recovering and functioning if the tires get airborn?

 

-----

 

 

[George S.]

The problem with all this practice this and practice that is many times you can't realize you need ABS until it kicks in, and even if you think you can recognize instances where you can brake in a better way, reality has a way of happening upon you so fast that just the time you spend thinking about it, you'll lose whatever edge you have yourself believing that you have.

[autobahnracing28]

 

Glad you're getting some braking practice in. You have dual exhaust on your RT?!?!

 

Yes my bike is one of the rare 8 cylinder, 640 hp, dual exhaust versions either that or I am an idiot and stated with out thinking that it was coming from the left hand exhaust pipe. Thanks for pointing my stupidity out to the entire world I think I will go out and bang my head on a tree now

[autobahnracing28]

Silly rider, You will never out brake ABS!

 

I may not be a pro in your mind, but what ever my riding ability, what I personally am able to do is what is relevant.

 

I respect your opinion, but I challenge you to to take your bike out on a gravel road with normal chatter bumps and nail the brakes at about 35 mph.

 

My ABS rt takes a rough average of 12 ft longer to stop than my non ABS R1, a couple times it would completely freewheel and was a great deal longer. I know they are very different bikes but the majority of the difference is the ABS, not the bikes.

 

In loose gravel, straight line, no bumps, ABS stops about the same as non ABS but keeps the bike in a straight line. Non ABS stops about the same but I am crossed up a little.

 

On wet pavement this morning I admit the ABS is somewhat better than the non ABS.

 

Can't wait for the ice and snow to start

[tallman]

R1200 RT 119.4

'07 R1 117.9

data from Motorcyle Consumer News

link to '09/10 performance articles

 

 

Not looking to argue but modern ABS will out stop non ABS bikes comparing apples to apples, same model ABS and non ABS bike.

Saying an R1 will stop 12' shorter than a full dress sport touring bike isn't apples to apples wrt weight/wheelbase/tires etc.

 

And according to data above, the difference is 18 inches.

 

From another article.

 

"Test results from non-ABS motorcycles were noticeably more sensitive to rider performance variability. The data in Table 2 include the best stopping distances obtained without ABS, compared to the average braking performance obtained with ABS. The average results were favored for presenting the performance with ABS because the best results could be more representative of threshold braking, whereby the ABS operated for only a portion of the entire test. Despite being compared to the best stopping distances without ABS, the average results with ABS provided an overall reduction in stopping distance of 5%. The stopping distance reduction was more significant when the motorcycle was loaded (averaging 7%). The greatest stopping distance reduction (averaging 17%) was observed when only the rear foot pedal was applied to stop the motorcycle from 128 km/h"

link

 

 

So real world data and application favors ABS in almost every conceivable scenario.

Best wishes.

[autobahnracing28]

Ok, the R1 has a shorter stopping distance on pavement, it may have the same advantage on gravel also. I don't have the resources and am unable to test to the same standards as a magazine.

 

If I were to face a busy intersection or similar situation I would rather lock up the tires and lay a bike down, scrape off some speed, than go freewheeling into traffic.

 

At this point in my understanding, the more I think about it, the less I like ABS. It seems the marginal advantage ABS has in some situations is not worth the one or two where it falls short and gets you killed.

[JWMcDonald]

"At this point in my understanding, the more I think about it, the less I like ABS."

 

So just disable / remove the ABS and be done with it.

[Matts_12GS]

Make sure you check the level you fill your crankcase to. If it is overfilled sometimes windage will blow oil up into the airbox.

 

I had a similar issue where I had overfilled mine on the way to a trip and dropped the bike on the left side. It hydrolocked that cylinder but fortunately I didn't do any damage to the engine. I pulled the plug, blew the oil out and rode the bike 500 miles home. It smoked for the first 50 or so but cleaned up and I rode it another 10,000 or so before selling it.

[Ken H.]

Simply put an actuation of the ABS, any ABS is an after the fact event. It engages after traction has been lost. (Even if only milliseconds, it’s still after.)

 

Maximum deceleration is achieved at the traction limit (threshold braking), but when traction is not yet lost. I.e. before for the ABS engages. Thus theoretically a skilled rider can indeed out brake, decelerate the bike quicker without the use of (engagement of) an ABS system.

 

Once the ABS system has engaged that’s an indication that the amount of traction available to the rider to use for deceleration has been exceeded and the ABS system takes over to reduce the braking pressure in an attempt to regain traction enough to return to the point of maximum deceleration traction. But while that is going on time is lost. Depending upon the speed and sophistication of the ABS that time can be detectable, thus the ‘freewheel’ effect.

 

The engagement of the ABS is in every sense an indicator that the rider has failed to properly find and utilize the maximum traction available to decelerate for that situation and moment. (And almost always the situation is not a constant, so the braking maximizing rider has to vary his braking to the constantly changing condition.)

 

Now that being said, most all of us mere mortals fail to find and use that threshold braking point all the time. Meaning we are either underutilizing it and we could have stopped sooner than we did, or we overshoot it and the ABS attempts to compensate for our failure. Which also means we could have stopped sooner than we did. But not necessarily sooner than had we continued our (again we’re talking in terms of milliseconds) inappropriate over braking for the traction available at ever changing moments.

 

ABS saves our bacon not because it can out brake a rider, it saves our bacon from our own ineptitude at maximized threshold braking. Which is not necessary a bad thing.

 

[Ken H.]

Am I reading in this responses that the ABS has trouble recovering and functioning if the tires get airborn?

 

-----

Yes. But so does a rider operating the brakes while the wheel is airborne.

 

There is no traction available during that time to utilized for deceleration. The ABS system can not do a calculation on how much to reduce braking pressure to reestablish the maximum braking threshold until a few hundred milliseconds (when for example talking about over a washboard) after the tire re-contacts a surface. And that takes time. How long depends upon the sophistication of the system, but time (again often in milliseconds) never the less.

 

No difference than a rider w/o ABS actually. During the period of time the tire is airborne the rider has no traction frame of reference to use to decided how much braking force to apply either so deceleration can continue once tire contact returns.

 

[Dave_zoom_zoom]

Simply put an actuation of the ABS, any ABS is an after the fact event. It engages after traction has been lost. (Even if only milliseconds, it’s still after.)

 

Maximum deceleration is achieved at the traction limit (threshold braking), but when traction is not yet lost. I.e. before for the ABS engages. Thus theoretically a skilled rider can indeed out brake, decelerate the bike quicker without the use of (engagement of) an ABS system.

 

Once the ABS system has engaged that’s an indication that the amount of traction available to the rider to use for deceleration has been exceeded and the ABS system takes over to reduce the braking pressure in an attempt to regain traction enough to return to the point of maximum deceleration traction. But while that is going on time is lost. Depending upon the speed and sophistication of the ABS that time can be detectable, thus the ‘freewheel’ effect.

 

The engagement of the ABS is in every sense an indicator that the rider has failed to properly find and utilize the maximum traction available to decelerate for that situation and moment. (And almost always the situation is not a constant, so the braking maximizing rider has to vary his braking to the constantly changing condition.)

 

Now that being said, most all of us mere mortals fail to find and use that threshold braking point all the time. Meaning we are either underutilizing it and we could have stopped sooner than we did, or we overshoot it and the ABS attempts to compensate for our failure. Which also means we could have stopped sooner than we did. But not necessarily sooner than had we continued our (again we’re talking in terms of milliseconds) inappropriate over braking for the traction available at ever changing moments.

 

ABS saves our bacon not because it can out brake a rider, it saves our bacon from our own ineptitude at maximized threshold braking. Which is not necessary a bad thing.

 

 

Hi Ken

 

Excellent analogy. Much better that I could do.

 

However, It may be a bit more accurate to use the term "lack of ability" rather than "ineptitude". A lack of ability could be due to unusual or rare circumstances it is not humanly possable to maximize threshold braking. It could also mean a lack of training and pratice that leaves us with a "lack of ability. My point is that a "lack of ability" term has less of a sting to it and may help to promote more effective braking pratices. Which I'm sure is your intention.

 

Thanks Ken

Dave

[tallman]

Ken and DAve,

Again, at the risk of redundancy.

Test data for modern ABS systems don't agree.

Those were professional riders testing the systems.

 

In only one test, and that was after 4 trials, could the professionala rider outbrake the ABS system's average, not the ABS system best stoppage, and by one foot.

 

So, yes, in theory what Ken said is true.

But real world testing my non-mere mortals does not provide the theoretical outcome, it showed something different.

And that was in a test situation where the professional rider

knew maximum braking was going going to be applied, without

real world/street issues like cars/dogs/road surface/etc.

 

We can discuss theory and data ad infinitum.

I concede that some systems of ABS in the real world in some situations can hinder stopping distances.

But how often are we trying to stop quickly going over rumble strips approaching a stop sign?

 

Any anecdotal testing results provided by you or me is merely that and does not stand the same scrutiny that testing in controlled situation with professional riders does.

 

In the real world we rarely know that the moment we need maximum braking is just about to occur.

In our own anecdotal testing we know we are going to brake and try to stop before point X.

If those pesky real world situtaions would just ID in advance, well...

Best wishes.

[Ken H.]

It may be a bit more accurate to use the term "lack of ability" rather than "ineptitude". A lack of ability could be due to unusual or rare circumstances it is not humanly possable to maximize threshold braking. It could also mean a lack of training and pratice that leaves us with a "lack of ability. My point is that a "lack of ability" term has less of a sting to it and may help to promote more effective braking pratices. Which I'm sure is your intention.

Yes, and no offence intended by my poor choice of the word “ineptitude.”

 

I think the only reason ABS can out brake the vast majority of us in the real world is because it can evaluate the rapidly changing data surrounding ongoing deceleration and adjust braking pressures faster than the majority of us can. (Although as we saw in the original 1150 series' ABS implementation that assumption is far more questionable as that system is rather slow.)

 

ABS activation (even in a cage for that matter) represents a failure by the quite human operator. Not to say a failure most of us could always avoid, but one never-the-less.

 

I think the bottom line lesson is learn to maximum brake as if you didn’t have ABS; then be darn glad you do.

 

[tallman]

"I think the bottom line lesson is learn to maximum brake as if you didn’t have ABS; then be darn glad you do."

 

That essentially is what I told customers when selling the bikes.

With a few caveats wrt certain conditions.

 

ABS has never caused me a problem and has helped me avoid

several no brain moves by other drivers/animals/and furniture.