Servo brakes

[Marty Hill]

They stop the bike just fine. Better than fine.

If that was true we wouldn't be complaining.

 

 

Thats a joke!

[jaytee]

They stop the bike just fine. Better than fine.

If that was true we wouldn't be complaining.

 

Have you ever riden with servo brakes???

 

They do stop.

 

Sometimes a little too well (at slower speeds).

 

Thats why I dont get the complaining. Out of 6 bikes I have owned/rid on a regular basis the servo brakes on my R1200ST are the most confidence inspiring of the lot.

 

The caveat being that I am not a professional racer, nor do I use my bike to its limits on the track. But for my high-speed SoCal riding and moderate speed mountain riding (both of which I do a lot of) I can brake harder with more confidence on my servo brakes than with ANY other bike I have owned. What bikes, you might ask? Recently, FZ-1, Roadstar Warrior, SV1000S.

 

So, I respectfully, completely disagree with you.

 

JT

[Bob Palin]

They stop the bike just fine. Better than fine.

If that was true we wouldn't be complaining.

 

Have you ever riden with servo brakes???

126,000 miles on my 1150RT. I just posted a story to the hopping thread that explains my problem with them.

 

I will say however that the RT brakes are no better at stopping than the brakes on the 1990 ST1100 it replaced were. They are certainly no better than the brakes on my CBR600 were. Neither of those had ABS but that's not the question here (servos)

 

edit: argh I'm hoisted, when did my own petard get so touchy? My story relates to the ABS of course and it's really the whole servo/ABS/linked system I rant about.

[John in VA]

They do stop.

 

Sometimes a little too well (at slower speeds).

 

 

Sometimes a LOT too well at slower speeds, which is very annoying when the front dives unexpectedly -- and independently of the pressure on the brake lever. It's also annoying that when I hold the bike with a dead-steady pressure on the front brake lever on a steep incline (waiting to exit an underground parking garage), after 15 seconds or so the bike "resits" itself on its suspension, which is a bit startling, while emitting its typical whizz-zip-chirp-weeeeeez R2D2 sounds. My 1100 never did such unnecessary histrionics, and was, of course, completely silent.

 

At speed, my 06 brakes work well - but no better IMO than my 1100's non-powered brakes. The 07 1200's seem to have been improved by dropping this complex and noisy power system that only last year was "state of the art."

[russell_bynum]

So, I respectfully, completely disagree with you.

 

You disagree with BMW, too then...because they are in the process of doing away with the servo assist "Feature" on all the new bikes.

 

No system is perfect. Period. All systems have flaws and/or drawbacks. Period.

 

Some of you are just so busy getting roundel Tattoos and kneeling facing Munich and praising the God of Motorcycle Supremacy twice a day to actually recognize the faults and understand what that means for us, the rider.

[Bob Palin]

Some of you are just so busy getting roundel Tattoos and kneeling facing Munich and praising the God of Motorcycle Supremacy twice a day to actually recognize the faults and understand what that means for us, the rider.

Oooh, that's gonna leave a mark (and I agree totally)

[jaytee]

So, I respectfully, completely disagree with you.

 

You disagree with BMW, too then...because they are in the process of doing away with the servo assist "Feature" on all the new bikes.

 

No system is perfect. Period. All systems have flaws and/or drawbacks. Period.

 

Some of you are just so busy getting roundel Tattoos and kneeling facing Munich and praising the God of Motorcycle Supremacy twice a day to actually recognize the faults and understand what that means for us, the rider.

 

Bullcrap.

 

Never owned a BMW until this one. Don't care what color their roundels are. Never heard of a Farkle before this board. Don't care. Never said the servo/abs system was perfect. Try reading.

 

Now that I've blown off the steam generated by your semi-rude post insinuating that I am nothing more than an ass-kissing BMW wannabe who knows nothing about which I speak, why dont you try actually reading my posts instead of using your considerable talents at belittling everyone else's experiences and opinions to reflexively lash out at anyone who does not share your opinion.

 

/rant

 

 

My point is that they do function to stop the bike well. They may have their odd traits, and maybe its more complex than you would like, and maybe their odd traits are something you dont care for - fine. That doesnt mean they dont work.

 

JT

[jaytee]

I just posted a story to the hopping thread that explains my problem with them...

 

I went and read your post, and I agree with it. The linked ABS has its idiosyncracies, no doubt. Mine is only partially linked and is the only servo-assisted ABS type that I have direct experience with. Its a bit odd, but I really dont understand the reflexive hatred of it. IT stops. Sometimes a LOT better than a standard brake system. Sometimes worse than a mroe conventional system used by a skilled rider. So what? They still stop the bike.

 

JT

[Bob Palin]

I think the main problem that many of us have with the servo system is that we see it as unnecessary and overly complex which makes the bikes more expensive, harder to maintain and more likely to fail.

[jaytee]

Fair enough...

 

But for the typical user the partially linked servo-assisted ABS on my R1200ST is still better to have than the typical conventional brakes on all my other bikes. It may have been a step sideways/backwards for all you BMW owners, but coming from the Japanese bike world its a significant step forward for my uses (again, no track and I'm not a super-highly-skilled-motorcycle-ninja).

 

I think its a bit misleading for the old hands here to insinuate to new/potential owners that they are looking at a bike that is inordinately dangerous due to (non-existant) failure rates and quirky braking behavior.

 

JT

[russell_bynum]

Let's see...you said

 

I have to say, a lot of you guys sound down right religious in your hatred of a brake system that despite (because of?) its complexity - works.

 

For the most part, most of the time, the system works. Nobody is denying that. There are some situations in which it doesn't work particularly well. And system brings its own set of liabilities to the equation.

 

Ok, I grant it might not be how you would have had your ideal brake system designed - so what?

 

Um....so we talk about it. Enough people start saying the same thing and the manfacturer's respond. It took a while for BMW to let go of servos, but they responded to some of the other complaints within a couple of model years. One of the primary functions of a forum like is is to facilitate discussion...on the good and the bad.

 

 

They stop the bike just fine. Better than fine.

 

Except when they don't.

 

 

This seems truly a case of shut-up-and-ride.

 

And why would that be? Have we incorrectly identified flaws in the system? Have we incorrectly identified the impact of those flaws? Do you just disagree that the impact of those flaws is relevant? What's the issue here...why does it bother you that we see flaws in the system?

 

By the way, if your R1200ST is the only servo-equipped bike you've ridden, then you're not getting the complete picture. As I mentioned, BMW made some fairly substantial changes as the system evolved that improved it quite a bit. Servo brakes would not stop me from buying an R1200ST if that's the sort of bike that I wanted right now. I'd prefer that it didn't have the servos, but BMW fixed enough of the flaws by the time the R1200's came out that servo brakes would not stop me from buying the bike.

[Ken H.]

Slight Hijack

Right from BMW Motorrad

ADVANTAGES OF BMW'S NEW INTEGRAL ABS

 

• Monitoring of the tail and brake lights.

• Dimmed brake light replacing the taillight should the latter fail to operate.

 

I take it this no longer applies to the CanBus bikes in which the tail and brake lights are one and the same?

Yes it still applies. The ZFE module (of CANBus equipped bikes) sends a PWM (Pulse Width Modulated) square-wave to the bulb(s) which it changes depending upon function desired at any moment. Example, lengthens the square-wave's duration to make the bulb burn brighter for braking light.

 

There is either two single filament or one dual filament bulb depending upon model. In the event of a failure of a filament in any bulb another filament is used as a surrogate for the failed one by changing the PWM going to it.

 

/slight hijack

[jaytee]

Let's see...you said...

 

now that's a well thought out, well argued, reasoned post which I duly acknowledge as such. Thank you for the feedback and insights.

 

JT

[russell_bynum]

I think its a bit misleading for the old hands here to insinuate to new/potential owners that they are looking at a bike that is inordinately dangerous due to (non-existant) failure rates and quirky braking behavior.

 

Baloney. The system has flaws and quirks and a potential owner needs to know about that. Nobody has said that the failure rate is high (We HAVE seen reports of failures here, so it DOES happen, but it is pretty rare.) It DOES introduce added complexity, weight, and cost. It DOES make it more difficult to work on the bike (not to the point that a sufficiently dilligent DIY mechanic would have problems with it, but there IS more to it than the non-servo ABS system that preceeded it).

 

Potential owners can weigh that information against the percieved benefits and make an educated decision that meets their personal needs and preferences.

[Paul Mihalka]

This seems truly a case of shut-up-and-ride.

 

JT

This is about the only statement in this whole 6 page (more coming) thread that I can 100% agree with

[ltljohn]

WOW there is more difference of opinion in here than a thread about oil, tires and batteries.

[ghaverkamp]

WOW there is more difference of opinion in here than a thread about oil, tires and batteries.

 

Whoa, there. A thread about oil, tires, and batteries? I don't think the server could take it.

[steve.foote]

WOW there is more difference of opinion in here than a thread about oil, tires and batteries.

 

Whoa, there. A thread about oil, tires, and batteries? I don't think the server could take it.

 

Should we toss in climate change?

[ghaverkamp]

Should we toss in climate change?

 

I don't understand the question.

[IanW]

There is either two single filament or one dual filament bulb depending upon model. In the event of a failure of a filament in any bulb another filament is used as a surrogate for the failed one by changing the PWM going to it.

 

Ken

If there is only a single filament bulb in some models, and it blows, what happens then???

Ian

[AnRSguy]

I think its a bit misleading for the old hands here to insinuate to new/potential owners that they are looking at a bike that is inordinately dangerous due to (non-existant) failure rates and quirky braking behavior.

 

Baloney. The system has flaws and quirks and a potential owner needs to know about that. Nobody has said that the failure rate is high (We HAVE seen reports of failures here, so it DOES happen, but it is pretty rare.) It DOES introduce added complexity, weight, and cost. It DOES make it more difficult to work on the bike (not to the point that a sufficiently dilligent DIY mechanic would have problems with it, but there IS more to it than the non-servo ABS system that preceeded it).

 

Potential owners can weigh that information against the percieved benefits and make an educated decision that meets their personal needs and preferences.

 

From the lack of significant numbers of servo failures versus the number of failures of final drives and splines it would seem that you are on the wrong topic if you want to discourage potential buyers from buying a particular bike.

 

It also doesn't seem that BMW has listened one iota to those complaints.

[russell_bynum]

From the lack of significant numbers of servo failures versus the number of failures of final drives and splines it would seem that you are on the wrong topic if you want to discourage potential buyers from buying a particular bike.

 

Good grief.

 

 

I don't give a flying flip what kind of brake system you or anyone else decides they want. I'm not trying to convince anyone of anything...other than the facts.

 

If you look at the facts and decide the servo system is what you want, or if it isn't important to you either way, or even if you don't like it but like everything else about the bike enough to just live with the servos....it makes no difference to me whatsoever.

 

What I'm after providing accurate and complete information so you can make your own educated decision.

 

As for the failure rate of the servo brakes, all I said was that we HAVE SEEN some failures reported here. I also said that these failures are pretty rare...but they DO happen. And that just follows logic...when you add components and complexity to a system, all things being equal, you reduce the reliability of that system. That's just the way it works and it doesn't matter if we're talking about BMW motorcycles or pencils...more complexity means moreopportunity for failure.

[AnRSguy]

From the lack of significant numbers of servo failures versus the number of failures of final drives and splines it would seem that you are on the wrong topic if you want to discourage potential buyers from buying a particular bike.

 

Good grief.

 

 

I don't give a flying flip what kind of brake system you or anyone else decides they want. I'm not trying to convince anyone of anything...other than the facts.

 

If you look at the facts and decide the servo system is what you want, or if it isn't important to you either way, or even if you don't like it but like everything else about the bike enough to just live with the servos....it makes no difference to me whatsoever.

 

What I'm after providing accurate and complete information so you can make your own educated decision.

 

As for the failure rate of the servo brakes, all I said was that we HAVE SEEN some failures reported here. I also said that these failures are pretty rare...but they DO happen. And that just follows logic...when you add components and complexity to a system, all things being equal, you reduce the reliability of that system. That's just the way it works and it doesn't matter if we're talking about BMW motorcycles or pencils...more complexity means moreopportunity for failure.

 

Well if that's the case have you read the description of the "new" brake system? It sounds even more complex.

 

From BMW:

 

"Integral brake with electrohydraulic pressure generation.

To activate the integral function, brake pressure for the rear-brake is generated

actively via an electrohydraulic high-pressure pump as soon as the rider

pulls the handbrake lever. The pump is switched on automatically every time

the rider uses the front-wheel brake and is masterminded by the pressure

sensors in the front-wheel brake circuit. Geared to brake pressure on the front

wheel, appropriate pressure is built up automatically on the rear-brake in

accordance with the brake force distribution predetermined by the control unit,

the rear wheel thus being decelerated ideally with every application of the

front-wheel brake (semi-integral function).

Even when using the integral function, the rider has the option to brake the

rear wheel harder via the footbrake lever than the integral system as such

would allow. This he can do up to the rear wheel locking point where ABS cuts

in. Should the brake pressure applied by the rider be weaker than the pressure

generated via the integral function, the rider’s operation of the footbrake is

not taken into account and the rear-wheel brake is applied in accordance with

the integral function."

 

I wonder what the definition of a "electrohydraulic high-pressure pump" is?

[T__]

{quote] I wonder what the definition of a "electrohydraulic high-pressure pump" is?

 

Answer= An electric motor driving a hydraulic pump..

 

Twisty

[smiller]

It also doesn't seem that BMW has listened one iota to those complaints.

Hence the totally redesigned system on the 2007 bikes.

 

The new system does indeed address many of the nits with the prior servo brake system (removing the 'power assist' feature), and BMW even brags about its superiority and improved feel.

[russell_bynum]

Well if that's the case have you read the description of the "new" brake system? It sounds even more complex.

 

Indeed. The unnecessary complexity and subsequent lack of reliability is one of the reasons I did not purchase a new BMW when I went looking for a bike to replace my R1100RT.

 

But...one thing that this system has going for it vs. the previous servo system is a failure of the servo...errr....I mean "electrohydraulic high-pressure pump" only results in a reduction of braking force on the rear brake. And...I'm assuming (though I admit that I have not tested this) that residual braking is more along the lines of the other R1200 bikes rather than the original implementation on the R1150's...which is to say there's less difference between "servos working" and "servos failed".

[smiller]

But...one thing that this system has going for it vs. the previous servo system is a failure of the servo...errr....I mean "electrohydraulic high-pressure pump" only results in a reduction of braking force on the rear brake.

Actually I think it doesn't even do that. My understanding is that a failure in the servo unit in the 2007 system will affect the linkage between front and rear (as in there won't be any), but not the front or rear brakes themselves, and that the brake system will remain fully functional (albeit without linkage and/or ABS) if the system fails. Not certain about that though.

[russell_bynum]

But...one thing that this system has going for it vs. the previous servo system is a failure of the servo...errr....I mean "electrohydraulic high-pressure pump" only results in a reduction of braking force on the rear brake.

Actually I think it doesn't even do that. My understanding is that a failure in the servo unit in the 2007 system will affect the linkage between front and rear (as in there won't be any), but not the front or rear brakes themselves. Not certain about that thought.

 

Good catch. I believe that is correct.

 

So...the worst case would be that if you only brake with the front brake lever, you will see a slight reduction in your stopping distance due to the fact that the rear brake is not also being used by the servo.

[HexHead]

I think its a bit misleading for the old hands here to insinuate to new/potential owners that they are looking at a bike that is inordinately dangerous due to (non-existant) failure rates and quirky braking behavior.

 

They're just bitter because they're still riding around on R1100RTs.

 

I don't get the problems with the servo brakes at low speeds etc. NEVER been an issue for me. And I love when a car with a dog inside pulls up alongside at a red light.

[russell_bynum]

They're just bitter because they're still riding around on R1100RTs.

 

Not hardly.

[Marty Hill]

But...one thing that this system has going for it vs. the previous servo system is a failure of the servo...errr....I mean "electrohydraulic high-pressure pump" only results in a reduction of braking force on the rear brake.

Actually I think it doesn't even do that. My understanding is that a failure in the servo unit in the 2007 system will affect the linkage between front and rear (as in there won't be any), but not the front or rear brakes themselves, and that the brake system will remain fully functional (albeit without linkage and/or ABS) if the system fails. Not certain about that though.

 

I'm lost here. BMW tells me that my '07 has non servo brakes. Have they lied? Was I cheated? Will someone send me a recording of the servo whine that I can play while I ride?

[HexHead]

{quote] I wonder what the definition of a "electrohydraulic high-pressure pump" is?

 

Answer= An electric motor driving a hydraulic pump..

 

Twisty

 

In other words, the new "non-servo" ABS brakes only don't have the servo on the front brake circuit. It's still there on the rear, So basically, you just don't hear it whining when stopped.

[smiller]

In other words, the new "non-servo" ABS brakes only don't have the servo on the front brake circuit. It's still there on the rear, So basically, you just don't hear it whining when stopped.

No, the 2007 brakes do not have servo actuation of the front or rear brakes, only the linkage between the front and rear brakes. It is a pretty big departure from the 'power assist' concept of the prior system.

[AnRSguy]

It also doesn't seem that BMW has listened one iota to those complaints.

Hence the totally redesigned system on the 2007 bikes.

 

The new system does indeed address many of the nits with the prior servo brake system (removing the 'power assist' feature), and BMW even brags about its superiority and improved feel.

 

I was actually referring to the final drive and spline problems.

[smiller]

I was actually referring to the final drive and spline problems.

Oops, yes, re-reading the comment I see what you were saying. Sorry.

[T__]

{quote] I wonder what the definition of a "electrohydraulic high-pressure pump" is?

 

Answer= An electric motor driving a hydraulic pump..

 

Twisty

 

In other words, the new "non-servo" ABS brakes only don't have the servo on the front brake circuit. It's still there on the rear, So basically, you just don't hear it whining when stopped.

 

HexHead, I haven’t seen the actual 07 BMW ABS architecture yet but by reading between the lines on the BMW promo publications it looks like the front brake is conventional NON POWERED with a possible servo kick in at front wheel ABS initiation.. (re. possible front servo here)

In using the front brake lever ONLY it looks like the front functions in the conventional plain old hydraulic method BUT at the same time the REAR servo motor comes on & applies the rear brake at a force determined by the front brake pressure, vehicle speed, & front/rear wheel slip rate delta.. If the rear brake pedal is also used it looks like the system ignores the rear brake pedal input IF the brake pedal pressure is below the current servo pressure threshold.. If the rear brake pedal pressure is ABOVE the servo pressure threshold the system will then allow the added pressure to add more rear braking power (up to the point of REAR ABS initiation.. It doesn’t look like the rear pedal is linked to the front brakes..

 

I do like the new BMW system with the partial linking & it looks like they have found a way to get the front ABS response times & modulation frequency (& TOTAL brake release) without needing a constant running front servo..

 

Twisty

[AnRSguy]

Well read and said Twisty. That's the same info that I read and referenced earlier. Let's just hope that there aren't any bugs in it.

[bimmers]

ignorance is no defence in court. I am flabbergasted over the ignorance of facts. I am also aghast over the stoneage mentality of BMW riders (u are supposed to be technologically savvy and progressive).

How many automobiles or in particular race cars come without linked and servo assist brakes? Not too many winning cars anyway. How many of you are driving cars without power brakes (and power this and that)? Hardly one I would guess.

Those who like ABS and servo (power assist) and linked can choose it those who don't can be without it.

As a technologically minded rider without the urge to at this age become a racer I do feel safer with both ABS and linked brakes on a heavy bike. I ride the Ducati without power and links and ABS without a problem so WHAT IS THE PROBLEM?

No issues with the 1200RT brakes so far.

 

h

[smiller]

u are supposed to be technologically savvy

We are.

[russell_bynum]

How many of you are driving cars without power brakes (and power this and that)? Hardly one I would guess.

 

 

 

You've got to be freaking kidding me.

 

My truck weighs 6800lbs. My Motorcycle weighs 410lbs. I think there might be a slight difference in the amount of braking force needed to stop my 410lbs motorcycle vs my truck which weighs SIXTEEN TIMES MORE!!!

 

 

My car weighs 2400lbs and also has power brakes. But FWIW, I've disconnected the power steering because I like the feedback better and the only time it's ever even remotely issue is manuvering around at very low speed (parking lots).

 

Not that my car's braking system (or power steering, or pretty much every other system in 4-wheeled vehicles) is remotely relevant in a discussion about motorcycle brakes.

 

Even my big-ass RT...I could put it on its nose with one finger (and no servos). Tell me again why I need assistance applying more braking pressure.

 

 

Those who like ABS and servo (power assist) and linked can choose it those who don't can be without it.

 

Absolutely.

 

My gripe is that it seems that a big chunk of the "I like servos/linked brakes/ABS/whatever" people don't actually have the foggiest clue what they're talking about. They get technologies mixed up (i.e. "I like linked brakes because the other day I jammed on my brakes when someone pulled in front of me and the wheels didn't lock." Linked brakes had nothing to do with that...that's ABS.) or they just spout the marketing mumbo jumbo without actually knowing or understanding what the hell they're talking about.

 

That's not to say that everyone who likes <insert technology feature here> is like that...there are quite a few who understand the systems, understand their flaws and limitations, and have decided that they are a "good thing" for their riding needs. That's great. For the record, I like ABS on street bikes (mine doesn't have it and that isn't a deal breaker for me, but if it were available and implemented well, I'd have it). I see some nice benefits (and few drawbacks) to partially linked brakes (i.e. the pedal controls only the rear brake, but the lever controls both), especially on a long wheelbase touring bike. It wouldn't be of much use on my sportbike because the short wheelbase means the rear wheel is unweighted (and therefore not doing much to help slow you down) very easily. I don't care for servo assist (as it was implemented on any of the pre-2007 bikes), but it would not stop me from buying one of those bikes...particularly the later implementations on the R1200's starting in 2005. I'd rather go without servo, but like I said...it isn't a deal breaker. I've ridden several fully-linked bikes (both controls actuate both brakes) and that would be a deal breaker for me.

 

I do feel safer with both ABS and linked brakes on a heavy bike.

 

Good for you. We're not talking about linked brakes or ABS...we're talking about servo-assisted brakes.

[Ken H.]

If there is only a single filament bulb in some models, and it blows, what happens then???

Ian

The models with single filament bulbs, e.g. the RT, have two bulbs, the models with one bulb, e.g. the GS, have dual filaments in the single bulb. Obviously if two filaments blow in either configuration the back of the bike is dark. But you will also have a dash indicator telling you that it has happened.

[Ken H.]

I'm lost here. BMW tells me that my '07 has non servo brakes. Have they lied? Was I cheated? Will someone send me a recording of the servo whine that I can play while I ride?

Kind of depends upon use of the word "servo". Generally when people (include BMW) say the '07s do not have servo brakes, what they are saying is that the servo power assist function of the brakes since 2002 is gone.

 

But there is still a single servo motor (electro-hydraulic pump) in the ABS controller that provides proportional front to back linking when the front lever is applied.

 

Unfortunately (???) it is now a quiet one!

[Marty Hill]

Ken,

 

Thanks for the explanation.

 

Guess that means I've made another mistake/have another BMW with suspect brakes/fd/canbus and who knows what else.

 

Will I never learn?

[SageRider]

...Will I never learn?

Marty,

Time to buy another bike....

[Marty Hill]

Hey Michael,

 

Yeah, I hear the '08's come without brakes...problems solved.

[Todd_Z1]

100% agree with Killer. I share the same complaint. I don't need an electric motor to generate braking force, that is what mother nature gave me adrenaline for.

 

Cheers!

 

I think the main problem that many of us have with the servo system is that we see it as unnecessary and overly complex which makes the bikes more expensive, harder to maintain and more likely to fail.

[Todd_Z1]

That's right Marty, real men don't use brakes.

 

Cheers!

 

Hey Michael,

 

Yeah, I hear the '08's come without brakes...problems solved.

[Marty Hill]

Hey Todd,

 

It's tough on shoes tho.

[Matts_12GS]

So, what kind of oil does the battery in the new servo pump run on? Do the new brakes work better on set of tires?

 

 

[tallman]

But...one thing that this system has going for it vs. the previous servo system is a failure of the servo...errr....I mean "electrohydraulic high-pressure pump" only results in a reduction of braking force on the rear brake.

Actually I think it doesn't even do that. My understanding is that a failure in the servo unit in the 2007 system will affect the linkage between front and rear (as in there won't be any), but not the front or rear brakes themselves, and that the brake system will remain fully functional (albeit without linkage and/or ABS) if the system fails. Not certain about that though.

 

I'm lost here. BMW tells me that my '07 has non servo brakes. Have they lied? Was I cheated? Will someone send me a recording of the servo whine that I can play while I ride?

 

To go with your whine...

Boy am I glad I've deleted posts twice for this thread.

 

Loud brakes save lives.