Servo brakes

[Matts_12GS]

Just got back from doing some comparison sitting amongst Japan, Inc and a few BMWs and it seems that one member of this household has fallen in love w/an R1150RS.

 

It has the servo brakes but I don't know about them other than they source of nearly as much animosity as paper/plastic, metlzer/dunlop nicky/roger lee...

 

Can someone give me a primer on how the work and the implications for them without a (coffee) bar fight breaking out?

[Sidmariner]

Oh no! Not Again!

 

OK, I'll start this round. I really like them, which according to many here makes me an incompetent rider. Mine have been perfectly reliable, don't make horrible noises like some might complain, and so far have not contributed to any close calls or accidents. They can definitely bring the bike to a controlled stop quickly, more quickly I believe than the brakes on my other bikes.

 

However, I still practice "proper" brake usage on my two K bikes, just to ensure I stay grounded in old technology and can defend my abilities before the experts.

[Matts_12GS]

yeah, but what is different in the system's design from non servo brakes?

[Calvin (no socks)]

Matt, I have two bikes with and 4 without.... I have 60k miles with the servo brakes and no problems... one finger braking... no worries...if it breaks... well then..... thats another thread.....

[jaytee]

Ok, as a new servo brake user I'll tell you what I can...

 

These are essentially partially linked power ABS brakes, which means less effort is required to brake with them. This is usually a good thing, and linked ABS works very well indeed for 95% of all riders. There are numerous actual controlled tests that have been done and ABS just flat out works in most cases.

 

That being said there are a few of caveats and idiosyncracies to servo brakes...

 

First, the caveats: First, if you are a very high performance rider who gets to know your vehicle so well that you routinely use the brakes at their limit of adhesion on a regular basis, you may notice a difference working with ABS as it may let go right when you are expecting a minor loss of traction but are ok with it. Second, if you are a very high performance rider who uses braking to adjust a line while under extreme cornering, you might also notice a difference if you are at the limits of adhesion as the abs might let the brakes go when you are expecting a slight loss of traction. Third, controlled testing with very accomplished riders indicates that ABS servo brakes do *not* stop any faster (and *might* stop ever-so-slightly slower) than non-ABS brakes in dry conditions with near perfect pavement. NOTE: These same test, however, reveal that in less than ideal conditions the ABS outbrakes the traditional brakes every time.

 

As to the idiosyncracies, the first is that the servos make noise. When you hold a brake down you hear the little servos whining as they maintain preasure in the line. Secondly, if the key is off, you have no power brakes. This means you are back to traditional brakes that take substantial effort to use. They work fine, but you need to pull harder than normal. This can be a bit disconcerting in the garage when you are not expecting it, as it seems the bike will not stop unless you really clamp down on the brakes. third, the braking effort seems a bit inconsistant at speeds below 25mph or so, especially the front brake. This can result in abrupt stops if you are using the front brake lever (remember that using the front actuates both the front and back brakes). Finally, some people feel that the servo brakes give slightly less feedback about traction conditions while braking at the limits of adhesion.

 

Now, as to my personal impressions...

 

Whatever.

 

It is a braking system that has its own idiosyncracies, but I am not a professional racer, nor am I a professional rider who test these things. They flat-out stop. Period. The ABS is a great comfort as I am not constantly worried that I might lose traction on the front tire from over-agressive braking. Parking lot speeds, I just use the rear brake (which works quite well). I admit that the servo whine is a bit annoying in the garage, but once on the street it is a non-issue.

 

In the final analysis, these are no more differnt than say the brakes on a Harley as compared to the brakes on a sport bike: differnt, but both still quite servicable for their intended purpose, namely stopping the bike.

 

Hope this helps!

 

JT

[Matts_12GS]

Thanks JT, that's what I was looking for.

 

I think they'd be fine for my wife as a new rider and Calvin, if they break, I'm bringing to your house for help fixing them!!!

 

I just never knew what the hullaballoo was about them so I was trying to get my head around what was going on.

Thanks!

[Firefight911]

Now if I could ever get around to actually calling you, I'da told ya the hullabloo is all hot air.

 

 

After dealing with Richard (BeniciaRT_GT) and Matt (Bakerzdosen) at my house this weekend, and, of course, me being at work, it'sa wonder I have any sanity left in me!!! I needed to go to work for the rest!!

[Matts_12GS]

Well, I've not met Matt, but given the name he can't be all bad...

Richard though... I'm surprised he got there early enough to actually be seen before you went to work!

[Firefight911]

Well, I've not met Matt, but given the name he can't be all bad...

Richard though... I'm surprised he got there early enough to actually be seen before you went to work!

 

And he stayed 8 hours AFTER I left!!!! My poor wife and puppies!!!

[Matts_12GS]

Next time, tell Jaime just to put on her gear and leave... He gets the hint about 4-5 hours usually. That's what Danny said...

 

ring ring working man...

[russell_bynum]

Thanks JT, that's what I was looking for.

 

I think they'd be fine for my wife as a new rider and Calvin, if they break, I'm bringing to your house for help fixing them!!!

 

I just never knew what the hullaballoo was about them so I was trying to get my head around what was going on.

Thanks!

 

Just look for a 2001 or earlier R1100RS. Same bike as the 1150RS without the screwy brakes.

 

You do give up 50cc, but I would be astounded if anyone other than a dyno machine could tell the difference.

 

The 1150RS does have the partially linked servo ABS brakes...which is a big improvement over the fully-linked servo ABS brakes that were inflicted upon the RT. But still...the servos are an added bit of technology that makes the bike take longer to maintain, cost more to fix when they go out, servo failure is a fairly big deal if it happens when you're actually riding the bike, and the servos don't actually add anything positive to the equation.

 

If I found a "I'd be an idiot to pass this up" deal on an 1150RS, I'd take it, but given the choice, I'd rather have the R1100RS's non-servo ABS-II system.

[smiller]

But still...the servos are an added bit of technology that makes the bike take longer to maintain, cost more to fix when they go out, servo failure is a fairly big deal if it happens when you're actually riding the bike, and the servos don't actually add anything positive to the equation.

Which is why the servo brakes are often summed up as... a poor answer to a question nobody asked.

[russell_bynum]

But still...the servos are an added bit of technology that makes the bike take longer to maintain, cost more to fix when they go out, servo failure is a fairly big deal if it happens when you're actually riding the bike, and the servos don't actually add anything positive to the equation.

Which is why the servo brakes are often summed up as... a poor answer to a question nobody asked.

 

Well, I wasn't going to go there, but...yeah.

[Matts_12GS]

interesting.....

 

Neither deal I've seen on 1150s has been stellar, although I did see a nice deal on a fairly well ridden 1100RS not too far away. It was just barely broken in at 65K miles, probably has 3 or 4K more till the final drive or splines give out....

 

Speaking of FDs.... I was talking to a guy today in Dogtona about bikes.... 05 12GS, 110K MILES on the clock, on the 4th final drive.

 

Shite!!

[John Bentall]

I'll tell you what the hullabaloo was about - and that applies only to the 1150RT not the RS. On the 1150RT, which BMW reckons is designed to be ridden 2-up, fully laden, the brakes are fully integrated to maximize braking effect. In this configuration, the brake pedal operates the front brakes and well as the rear.

Quite a number of riders who use the rear brake to balance the bike at very low speeds and through corners, were annoyed because control of the machine had been taken away from them. This is good riding technique and I would have to agree with them. But folks were sloppy in their criticism and howled at the servo brakes in general, rather than just the integration aspect. Eventaully the 1200RT returned to partially integrated set-up in response to this.

However......many, many, many riders are perfectly happy with the 1150RT set-up.

Servo brakes were the best that BMWs ABS system supplier could come up with at the time. Improvements in technology relating to the speed of control of the ABS shuttle valve (from a new ABS supplier) means that servos are no longer required.

[motorman587]

I will add my $.02. When we got them as a cop bike I told folks that servo brakes, which a whine to them at a red light, act as a power brakes on a car.

 

With out the key on the servo brakes do not work, but you still have brakes, just got to pull/push harder.

 

Servo brakes were made for the people who lack in training in the use of brakes. Most people are scared, again lack of training, in the use of motorcycle brakes. Servo brakes took out the fear factor in the squeeze of the front brake lever. Non trained person have a % where their inital squeeze in the front level is lacking in the fear of locking the front brake. The servo brakes is suppost to add in that area That is why serious motorcycle riders had them. We got use to them and never had problems with them.

[tallman]

Thanks JT, that's what I was looking for.

 

I think they'd be fine for my wife as a new rider and Calvin, if they break, I'm bringing to your house for help fixing them!!!

 

I just never knew what the hullaballoo was about them so I was trying to get my head around what was going on.

Thanks!

 

Just look for a 2001 or earlier R1100RS. Same bike as the 1150RS without the screwy brakes.

 

You do give up 50cc, but I would be astounded if anyone other than a dyno machine could tell the difference.

 

The 1150RS does have the partially linked servo ABS brakes...which is a big improvement over the fully-linked servo ABS brakes that were inflicted upon the RT. But still...the servos are an added bit of technology that makes the bike take longer to maintain, cost more to fix when they go out, servo failure is a fairly big deal if it happens when you're actually riding the bike, and the servos don't actually add anything positive to the equation.

 

If I found a "I'd be an idiot to pass this up" deal on an 1150RS, I'd take it, but given the choice, I'd rather have the R1100RS's non-servo ABS-II system.

 

1150's have 6th gear, different throttle cable routing and few other diffs.

I put 45k on a '96 R1100RSL w/ABS II and loved the bike.

I think the 1150 adds a bit more to the equation and wouldn't pass up one because of the brake changes.

.02

[russell_bynum]

1150's have 6th gear, different throttle cable routing and few other diffs.

I put 45k on a '96 R1100RSL w/ABS II and loved the bike.

I think the 1150 adds a bit more to the equation and wouldn't pass up one because of the brake changes.

.02

 

6th gear: I don't recall what the ratios are, but if it is the idiotically tall 6th that the R1150RT gets, then I would consider than a drawback, not a feature.

 

How is the throttle cable routing different? Lisa's RS is exactly like my 1100RT in that regard, and I've helped a few R1150RT guys change their throttle cables...other than the different fast idle setup, it seemed exactly the same to me.

[russell_bynum]

I'll tell you what the hullabaloo was about - and that applies only to the 1150RT not the RS. On the 1150RT, which BMW reckons is designed to be ridden 2-up, fully laden, the brakes are fully integrated to maximize braking effect. In this configuration, the brake pedal operates the front brakes and well as the rear.

Quite a number of riders who use the rear brake to balance the bike at very low speeds and through corners, were annoyed because control of the machine had been taken away from them. This is good riding technique and I would have to agree with them. But folks were sloppy in their criticism and howled at the servo brakes in general, rather than just the integration aspect. Eventaully the 1200RT returned to partially integrated set-up in response to this.

However......many, many, many riders are perfectly happy with the 1150RT set-up.

Servo brakes were the best that BMWs ABS system supplier could come up with at the time. Improvements in technology relating to the speed of control of the ABS shuttle valve (from a new ABS supplier) means that servos are no longer required.

 

Wrong.

 

 

Yes....the fully linked setup where the rear pedal acuates the front brake was the biggest complaint about the "new" brakes on the R1150RT.

 

And yes...the 1150RS (along with the K1200RS and I think the R1150R) got the much more intelligent partially linked system, which removed the biggest criticism for the new brakes.

 

But the servos are still an added bit of tech that don't add anything worthwhile, make the bike harder to work on, and create another point of failure. And a servo failure leaves you with "residual braking" only, which means that you might suddenly find yourself with a fraction of the braking power you were expecting.

 

So....linking is not the only reason to dislike the braking system that includes servos.

[sgendler]

what? No one is going to mention the anti-stoppie 'smarts' built into the servo brakes which causes th front brake to let go when the rear wheel locks up when braking over a bumpy surface? If there was a single reason to complain about the servo brakes, it was braking on the bumpy approach to a stop light or when lane splitting and bouncing off a bott's dot. In either case, you can easily wind up with no braking whatsoever for a half second or so. It is very disconcerting, utterly unavoidable (since you can't apply the front without the rear brake), and totally useless. Between that and the near total lack of braking when the servos die (just turn off the ignition to see what that will be like - then imagine what will happen when you discover that effect only when applying the brakes on the way into a corner or while approaching a stoplight or stopped car), and I'd say do what you can to avoid the servo brakes, especially if it means spending LESS money.

 

--sam

[russell_bynum]

what? No one is going to mention the anti-stoppie 'smarts' built into the servo brakes which causes th front brake to let go when the rear wheel locks up when braking over a bumpy surface? If there was a single reason to complain about the servo brakes, it was braking on the bumpy approach to a stop light or when lane splitting and bouncing off a bott's dot. In either case, you can easily wind up with no braking whatsoever for a half second or so. It is very disconcerting, utterly unavoidable (since you can't apply the front without the rear brake), and totally useless. Between that and the near total lack of braking when the servos die (just turn off the ignition to see what that will be like - then imagine what will happen when you discover that effect only when applying the brakes on the way into a corner or while approaching a stoplight or stopped car), and I'd say do what you can to avoid the servo brakes, especially if it means spending LESS money.

 

--sam

 

Yeah, there's that, too.

[tallman]

Early RS's had a change where the throttle cable split and hooked up w/2others at a Bowden connection (sumptin like dat) so there is a diff depending on which years.

Also, valve sizes differed in early models.

Very early ones had some tranny issues.

Sixth gear "overdrive" for a novice rider would be a benefit IMO. She might be riding a bit differently than you do and I don't think it was going to be a track bike.

I found 5 gears to be fine on mine, and used 4th for most situation until reaching XXX speed, and then only under closed road conditions on private property.

I always liked the RS/RSL version Boxer the best.

[Bob Palin]

what? No one is going to mention the anti-stoppie 'smarts' built into the servo brakes which causes th front brake to let go when the rear wheel locks up when braking over a bumpy surface?

Oh OK, there is that too. Happened to me just Friday in Bryce, what appeared to be a perfectly smooth road and suddenly the "ice patch" effect kicked in. After all this time it doesn't panic me any more but I have been left half way out in a cross street more than once due to this effect. I have also had the brakes go into residual mode without my knowing it, I re-started the motor at the top of a steep driveway and at the first corner discovered I had "no" brakes, ran off the far side of the road, no warning lights at all. I haven't been able to reproduce this problem so I don't know how to avoid it, hasn't happened again in over 100,000 miles. I'm used to the servo/linked/ABS brakes now but I still don't like them and would be reluctant to buy another bike with them.

[Matts_12GS]

What is the RSL? What makes it different from an RS?

Also, what is considered an early or late? I know there were 94/95 model years... Are you talking about early RS in general? Early 1100, early 1150?

 

[Paul Mihalka]

If you had to cross Kansas or Nebraska you'd love the long sixth gear...

[smiller]

If you had to cross Kansas or Nebraska you'd love the long sixth gear...

Only if I had a V1 at the ready...

[Bob Palin]

If you had to cross Kansas or Nebraska you'd love the long sixth gear...

Only if I had a V1 at the ready...

Sixth gear is really good for US50 across Nevada...

[russell_bynum]

If you had to cross Kansas or Nebraska you'd love the long sixth gear...

Only if I had a V1 at the ready...

Sixth gear is really good for US50 across Nevada...

 

The only time I had an 1150 up to speed (Leslie's RT), it was actually faster in 5th gear than 6th. 6th was just way too tall.

[Firefight911]

If you had to cross Kansas or Nebraska you'd love the long sixth gear...

Only if I had a V1 at the ready...

Sixth gear is really good for US50 across Nevada...

 

Why yes it is!!!!!!

 

 

Although, since I got out of this as a speeding ticket, did it really happen????

[Boffin]

If you had to cross Kansas or Nebraska you'd love the long sixth gear...

Only if I had a V1 at the ready...

Sixth gear is really good for US50 across Nevada...

 

The only time I had an 1150 up to speed (Leslie's RT), it was actually faster in 5th gear than 6th. 6th was just way too tall.

 

6th was advertised an overdrive gear over here, good for motorway/autoroute/autobahn cruising, less useful for normal riding. My complaint with the 6-speed RT box is that if 6th was intended as overdrive then 5th is not tall enough - they should have kept the 1100 ratios and added a cruising gear.

 

As to the servo brakes, another vote for a cure for a non existant problem. I did check out the operation of the servos and residual braking on a brake testing machine during a UK tech inspection a while back. Servo Brake data thread .

 

Andy

[russell_bynum]

My complaint with the 6-speed RT box is that if 6th was intended as overdrive then 5th is not tall enough - they should have kept the 1100 ratios and added a cruising gear.

 

Yeah, that would have been great.

[Stan Walker]

If there was a single reason to complain about the servo brakes, it was braking on the bumpy approach to a stop light or when lane splitting and bouncing off a bott's dot.

 

Pretty much doesn't do this if you are on both brakes at the same time. In short, don't just use the front brake lever to actuate both brakes, use both the front lever and the foot brake pedal.

 

Stan

[Bob Palin]

If there was a single reason to complain about the servo brakes, it was braking on the bumpy approach to a stop light or when lane splitting and bouncing off a bott's dot.

 

Pretty much doesn't do this if you are on both brakes at the same time. In short, don't just use the front brake lever to actuate both brakes, use both the front lever and the foot brake pedal.

 

Stan

Agreed, but isn't it odd that they would build a braking system that actuates both brakes from either control but then forces you to use both

[Ken H.]

Just don't confuse "servo brakes", i.e. power assisted brakes, with ABS brakes, with linked brakes. Three separate, distinct things that have been used in various combinations on various BMW models.

[Matts_12GS]

I can't believe that I'm asking Ken for advice...

 

So, to clarify, this is power assisted, linked front to rear (right handle) NOT rear to front (right pedal) right?

[tallman]

Matt,

RSL had a full fairing, it was an RS w/the lower fairing portion.

Of the 26,000+ RS’s sold, only @ 1200 were RSL’s.

To Confuse matters, once the RS was only available as an RS, post 1996, the RSL version was sold as the rS in Canada, and possibly Europe.

 

1994

 

1996 last year imported

The full lower fairing was prone to heat up where the pipes were if bike was left idling for long periods and allegedly a fire happened so it was DC’d here.

But, still available elsewhere.

The “early” model 93-95 9I think) had different valves, the Bowden cable changes were also around ‘96 as I remember mine differing in length from others.

The 1150's were pretty much the same each year (I think).

[Matts_12GS]

Thanks!

[John Bentall]

I can't believe that I'm asking Ken for advice...

 

So, to clarify, this is power assisted, linked front to rear (right handle) NOT rear to front (right pedal) right?

 

Correct, on the R1150RS

[MotorinLA]

If there was a single reason to complain about the servo brakes, it was braking on the bumpy approach to a stop light or when lane splitting and bouncing off a bott's dot.

 

Pretty much doesn't do this if you are on both brakes at the same time. In short, don't just use the front brake lever to actuate both brakes, use both the front lever and the foot brake pedal.

 

Stan

Agreed, but isn't it odd that they would build a braking system that actuates both brakes from either control but then forces you to use both

 

I think they were trying to compensate for the "idiot" factor, obviously they failed...

[Ken H.]

I can't believe that I'm asking Ken for advice...

 

So, to clarify, this is power assisted, linked front to rear (right handle) NOT rear to front (right pedal) right?

The only boxer model that had fully linked brakes, linked front to rear (right handle) and rear to front (right pedal) is the R1150RT.

[Bob Palin]

Agreed, but isn't it odd that they would build a braking system that actuates both brakes from either control but then forces you to use both

I think they were trying to compensate for the "idiot" factor, obviously they failed...

I think I've been dissed!

[Matts_12GS]

I can't believe that I'm asking Ken for advice...

 

So, to clarify, this is power assisted, linked front to rear (right handle) NOT rear to front (right pedal) right?

The only boxer model that had fully linked brakes, linked front to rear (right handle) and rear to front (right pedal) is the R1150RT.

 

Thanks Ken.

Just for that, I'm gonna go start my harley and complain about how loud it is!

Who said there've been no converts?

[MotorinLA]

Agreed, but isn't it odd that they would build a braking system that actuates both brakes from either control but then forces you to use both

I think they were trying to compensate for the "idiot" factor, obviously they failed...

I think I've been dissed!

 

Sorry Bob, the diss was intended for BMW. They apparently tried to make a bike that would be smarter than the rider, with the end result being that riders are back to doing the same thing they have always been doing (or should have been doing), which is to use both brakes.

[AnRSguy]

Just for the record, I like the servo brakes on my 1150RT. The maintainance isn't all that difficult and working on my bike is part of what I enjoy about it.

[Jim VonBaden]

Oh no! Not Again!

 

OK, I'll start this round. I really like them, which according to many here makes me an incompetent rider. Mine have been perfectly reliable, don't make horrible noises like some might complain, and so far have not contributed to any close calls or accidents. They can definitely bring the bike to a controlled stop quickly, more quickly I believe than the brakes on my other bikes.

 

However, I still practice "proper" brake usage on my two K bikes, just to ensure I stay grounded in old technology and can defend my abilities before the experts.

 

+1, and maintenance is easy as well, plus they have not proven to fail like everyone predicted.

 

Jim

 

PS I know, go ahead...

[russell_bynum]

1, and maintenance is easy as well, plus they have not proven to fail like everyone predicted.

 

BS.

 

They're a mechanical component...they can, and DO fail. We've had several reports of servo pump failures just here on this forum.

 

Frequently? No.

 

But it does happen.

 

And no, it doesn't make the bike impossibly difficult to work on, but it is substantially more time consuming to work on than the Non-servo ABS-II system.

 

Servo brakes would not prevent be from buying a bike that was otherwise "the one" (assuming they were not linked, or partially linked) but given the choice, I'll take the simpler, cheaper, easier to work on system that gives better feel and feedback, doesn't have the wonderful "ice patch" anti-stoppie "feature", and doesn't leave you with a fraction of your normal braking power with no warning in the event that it does fail.

[AnRSguy]

Servo failures have proven to be far more reliable than final drives, spines and several other components on BMW's. If ever there was a reason to NOT buy a particular bike, it certainly isn't servo brakes, linked or not.

[smiller]

Not to mention if a servo brake system fails it's a trip-ending situation as the bike is not safely ridable until you get it fixed, vs. a failure of the original ABS system which would cause no difficulty at all.

[Joe Frickin' Friday]

Servo failures have proven to be far more reliable than final drives, spines and several other components on BMW's.

 

That's not exactly a glowing endorsement.

 

Nor is it a really relevant comparison. If we're discussing reliability, servo-assisted brakes ought to be compared against the non-servo system they replace, in which case they come up short.

[Paul Mihalka]

Not to mention if a servo brake system fails it's a trip-ending situation as the bike is not safely ridable until you get it fixed, vs. a failure of the original ABS system which would cause no difficulty at all.

Not to defend servo brakes, just to voice my experience: R1150 servo brakes are ridable without the servo, carefully, with strong hand and foot . R1200 servo brakes are perfectly ridable without the servo working. Application force needed is not much more than conventional non-servo brakes.