1150RT Coordinated brakes

[Redman]

Excuse my ignorance, but just HOW coordinated are the brakes???

.. doesnt matter if use front lever or rear pedal, get the same braking on both front and rear?

.. front lever gives more braking on front? rear pedal gives more braking on rear?

.. lite braking coordinated different than heavy braking??

 

? ?

[dirtrider]

35 minutes ago, Redman said:

Excuse my ignorance, but just HOW coordinated are the brakes???

.. doesnt matter if use front lever or rear pedal, get the same braking on both front and rear?

.. front lever gives more braking on front? rear pedal gives more braking on rear?

.. lite braking coordinated different than heavy braking??

 

? ?

 

Afternoon Redman

 

When you say "coordinated" are you referring to linked or integrated?

 

 

There is a big DEPENDS on that--

 

Basic operation is that either front lever or rear brake pedal gives you both front & rear brake apply. From there is where the DEPENDS comes in.

 

For basic (non adapted) 'light' braking you get slightly more braking (very slight) from the end that you apply from, so rear brake pedal (only)  gives just slightly more rear braking at very light input. Same with the front, at very light front (only) apply you get just slightly more front brake bias (this is due to how the crossover passages & internal reaction pistons operate).

 

At heavier braking, once the brake system ABS  module computer has adapted or adjusted  to your load & stopping traction the ABS computer module automatically adjusts (adapts) the front/rear braking bias  & applies the proper front/rear bias for best stopping. (this works best if you only use the front brake lever for anything but very light rear pedal braking). If you start adding in more & more rear pedal pressure in the middle of a hard stop it can somewhat confuse the ABS computer & give you uneven braking until the ABS part kicks in & evens it out with individual brake release based on wheel spin-down or loss of traction.

 

Under very heavy (panic type) braking the ABS computer watches rear wheel spin down vs front wheel decel rate then can either adjust the braking bias or even release some front braking  to prevent excessive rear wheel lift (stoppie prevention).  You can still get a small  stoppie with a quick & very harsh front lever apply but it will be (should be anyhow) limited by the ABS system.  

 

The early  2002 1150RT is a little more unsettled than the later 1150RT bikes as BMW made some braking changes in the later 11500RT's  in both ABS module firmware updates & the biggest change was increasing the rear brake master cylinder piston size to get more fluid volume & better rear brake modulation  plus the firmware update  allowed the rear servo pump to turn off at light rear  brake pressure with bike sitting still (this was mainly a power saver to reduce battery run down in very heavy repeated stop & go conditions or  in repeated braking during training situations)

[Redman]

Coordinated.... integrated..... linked...... ah , um, 

 

I suppose I should have asked "duh, what my 02 1150RT got? I dont know nuffin bout it."

 

I gather that your discussion above does apply to my 02 RT.

And that it does more than just anti-lock. 

Thanks DR.

 

My habit that I learned from decades of conventional brakes is to most always use both brakes, and apply both harder if needed.

 But under heavier braking maybe let off the back a little to avoid it skidding as it become unweighted, sounds like the RT brakes does that for me.

Having to let off on the front to avoid a stoppie has never been a concern on my other (1980s) bikes.

 

I am thinking I should continue to use both brakes when on the RT,  just so I dont loose the habit for when on the other (1980s) bikes. I would welcome any further comments.

[dirtrider]

12 hours ago, Redman said:

 

I gather that your discussion above does apply to my 02 RT.

And that it does more than just anti-lock. 

 

I am thinking I should continue to use both brakes when on the RT,  just so I dont loose the habit for when on the other (1980s) bikes. I would welcome any further comments.

 

Morning Redman

 

Yes, it does apply to your 02 RT & it does do more than just a basic ABS anti-lock function.

 

A lot of 1150RT riders use both front & rear brake lever/pedal for the reason that you mention (keeping in practice of using both brakes on other non I-ABS bikes).

 

The later (after 2002) 1150RT I-ABS system was slightly better at allowing this as the larger rear master cylinder piston removed some of the rear pedal aggressiveness therefore allowing a little more rear brake pedal pressure without upsetting the adaptive braking function. 

 

You actually get slightly better (more even) braking using just the front lever as that allows the ABS computer to better adapt & more accurately balance front/rear braking but under normal, or normal light, braking it doesn't make that much difference.

 

BMW did come up with a better (partially integrated) system on the 1200 I-ABS gen2 braking system as that retained the front lever (only) integrated front/rear computer balanced braking but also allowed stand alone (rear brake pedal only) rear brake apply. 

 

It also allowed more rear brake apply than the front lever supplied if the rider really stepped hard on the rear pedal but if rear pedal pressure was under what the front lever (servo assist) supplied to the rear brake then it actually did or added nothing  to the rear braking.

 

The BMW 1150RT police bikes also had a slightly better braking system for experienced riders as it was a partially integrated system.  From front brake  lever both front & rear brakes were applied & computer balanced  but from the rear brake pedal 'only' then only the rear brake was applied. (kind of the best of both worlds). In fact some riders back in the 1150 era actually installed the RT-P (police bike) partially integrated ABS control module on their civilian 1150RT bikes to get the partially integrated braking system.   

 

Or, for very experienced 1150RT riders there is the option of completely removing the ABS & integrated power braking system then reverting to a conventional non-linked/ non-power-assisted/ non-ABS braking system. Actually gives a very smooth easy to modulate (non grabby)  conventional braking system but you do lose the ABS safety net.

 

 

 

 

[AndyS]

2 hours ago, dirtrider said:

Or, for very experienced 1150RT riders there is the option of completely removing the ABS & integrated power braking system then reverting to a conventional non-linked/ non-power-assisted/ non-ABS braking system. Actually gives a very smooth easy to modulate (non grabby)  conventional braking system but you do lose the ABS safety net.

 

+1 on that.

[pgm]

On 10/2/2019 at 6:56 AM, dirtrider said:

Or, for very experienced 1150RT riders there is the option of completely removing the ABS & integrated power braking system then reverting to a conventional non-linked/ non-power-assisted/ non-ABS braking system. Actually gives a very smooth easy to modulate (non grabby)  conventional braking system but you do lose the ABS safety net.

 

Not recommended, except for practice in an Advance Motorcycle course.

ABS is the number one reason for a huge drop in patrolman accidents by the CA Highway Dept when they switched from HD to BMW.

[dirtrider]

58 minutes ago, pgm said:

Not recommended, except for practice in an Advance Motorcycle course.

ABS is the number one reason for a huge drop in patrolman accidents by the CA Highway Dept when they switched from HD to BMW.

 

Afternoon Pgm

 

I would sure like the see the case studies showing  how it was determined that the  ABS brakes were  the number one reason for a huge drop in patrolman accidents. If it was gathered from non-ABS BMW vs ABS equipped BMW (like bikes) then it might be  somewhat meaningful.

 

Those are 2 very different motorcycles with vastly different riding positions, very different handling characteristics, greatly different braking systems with different rear brake pedal placement. (it's very easy to over-brake  the rear wheel on a non-ABS  HD police bike).

 

If in fact  the ABS is (was) the BIG defining difference then it sounds like  the  CA Highway Dept needs more & better thought out  police-bike braking training. No doubt that ABS (especially the newer ABS systems) are a more forgiving braking system but if ABS is the BIG or #1 factor in decreased motorcycle accidents then there is (or was)  something seriously lacking in  the LEO motor  training program.    

 

I can see ABS being a factor in rookie riders or inexperienced riders but much less of a factor in experienced  or well seasoned 'expert' riders.  

[pgm]

15 hours ago, dirtrider said:

I would sure like the see the case studies showing  how it was determined that the  ABS brakes were  the number one reason for a huge drop in patrolman accidents. If it was gathered from non-ABS BMW vs ABS equipped BMW (like bikes) then it might be  somewhat meaningful.

I believe you can find info on this in one or more of David Hough's books.  My recollection is that in less than ideal road conditions, rain slick or sand/leaves, it provides a margin of safety with quicker stops.  Not sure if still true, CA was training officers to "drop" their bikes if crash is imminent.  Shortest stopping distances is achieved by braking in a straight line, even with over-braking (skidding) rear wheel, than any other method - per Hough's books.  His writing makes a compelling argument for straight line braking with data, even if you do crash.

15 hours ago, dirtrider said:

I can see ABS being a factor in rookie riders or inexperienced riders but much less of a factor in experienced  or well seasoned 'expert' riders.  

Agreed.  This is why at my Advance Motorcycle Training course (circa 2005), they had us stand on the rear brake into a skid from 20 or 30 MPH.  The skill being developed was to show that you can easily control the bike with back wheel locked up and still stop quickly with modulating the front. 

 

To participate, I disabled the ABS on my '04R1150RT.  I still had a hard time locking up the rear wheel, and was able to stop in a shorter distance than any HD, Honda, MotoGuzi or other brand in the class.  I was left with the feeling that BMW engineered brakes beyond linking or ABS.  I still practice emergency braking at the beginning of each riding season to insure I know how to stop quickly in an emergency.  Plus, it's fun.

[dirtrider]

19 minutes ago, pgm said:

To participate, I disabled the ABS on my '04R1150RT.  I still had a hard time locking up the rear wheel, and was able to stop in a shorter distance than any HD, Honda, MotoGuzi or other brand in the class.  I was left with the feeling that BMW engineered brakes beyond linking or ABS.  I still practice emergency braking at the beginning of each riding season to insure I know how to stop quickly in an emergency.  Plus, it's fun.

 

 

Morning Pgm

 

How did you disable the ABS on your 1150RT?   (not easy to do)

 

Even if you disabled the ABS part  then you probably still had (retained) linked servo assist as I doubt that you could out-brake anything on an 1150RT with the servo pumps disabled.

[dirtrider]

46 minutes ago, pgm said:

I believe you can find info on this in one or more of David Hough's books.  My recollection is that in less than ideal road conditions, rain slick or sand/leaves, it provides a margin of safety with quicker stops.  Not sure if still true, CA was training officers to "drop" their bikes if crash is imminent.  Shortest stopping distances is achieved by braking in a straight line, even with over-braking (skidding) rear wheel, than any other method - per Hough's books.  His writing makes a compelling argument for straight line braking with data, even if you do crash.

Agreed.  This is why at my Advance Motorcycle Training course (circa 2005), they had us stand on the rear brake into a skid from 20 or 30 MPH.  The skill being developed was to show that you can easily control the bike with back wheel locked up and still stop quickly with modulating the front. 

 

 

Morning Pgm

 

I would still  like to see the actual case study reports, not someone's book, on HOW it was determined that  ABS brakes (alone) were  the number one reason for a huge drop in patrolman accidents given the fact that the motorcycles used were  completely different. No doubt that ABS is a contributor to motorcycle safety  but I'm still finding it difficult to believe that ABS (alone) was the biggest factor when the bikes were being ridden by supposedly  well trained & experienced LEO riders.

 

You even mentioned it yourself in the above that your BMW 1150RT (even without active ABS)  was able to stop in a shorter distance than any HD, Honda, MotoGuzi or other brand in the class.

[pgm]

In the U.S., major law enforcement agencies, including the California Highway Patrol and the New York City Police Department, require that all motorcycles in their fleets have ABS. 

 

BMW Group introduced the first motorcycle with ABS in 1988, and made them standard equipment on all of the bikes it sells in the U.S. in 2012. Harley-Davidson, the nation’s largest manufacturer with about half of all domestic sales, began offering ABS on police department motorcycles in 2005, and then as optional equipment on some civilian bikes starting in 2008. By 2014, Harley offered ABS as optional or standard on all of its models, albeit, an expensive option.

 

Crash Data:

https://www.fairwarning.org/wp-content/uploads/2017/03/2013absStudy.pdf

https://www.fairwarning.org/wp-content/uploads/2017/03/2014-ABS-study.pdf

https://www.fairwarning.org/wp-content/uploads/2017/03/Swedish_study.pdf

 

These studies do a solid job in statistically separating the impact of both experience and riding style from the addition of ABS. They directly address your inference that experience level is more important then ABS.  I just can't come up with the CHiPs specific info/data.

[dirtrider]

1 hour ago, pgm said:

In the U.S., major law enforcement agencies, including the California Highway Patrol and the New York City Police Department, require that all motorcycles in their fleets have ABS. 

 

BMW Group introduced the first motorcycle with ABS in 1988, and made them standard equipment on all of the bikes it sells in the U.S. in 2012. Harley-Davidson, the nation’s largest manufacturer with about half of all domestic sales, began offering ABS on police department motorcycles in 2005, and then as optional equipment on some civilian bikes starting in 2008. By 2014, Harley offered ABS as optional or standard on all of its models, albeit, an expensive option.

 

Crash Data:

https://www.fairwarning.org/wp-content/uploads/2017/03/2013absStudy.pdf

https://www.fairwarning.org/wp-content/uploads/2017/03/2014-ABS-study.pdf

https://www.fairwarning.org/wp-content/uploads/2017/03/Swedish_study.pdf

 

These studies do a solid job in statistically separating the impact of both experience and riding style from the addition of ABS. They directly address your inference that experience level is more important then ABS.  I just can't come up with the CHiPs specific info/data.

 

Afternoon Pgm

 

That is the data that I would be interested in  as couldn't find anything in the crash data that you posted mentioning that "ABS is the number one reason for a huge drop in patrolman accidents by the CA Highway Dept when they switched from HD to BMW".

 

The thing we don't have, & I would guess we will never have, is how much the accident rate dropped just due to the switch from HD to BMW as the BMW probably wasn't offered without ABS.   

 

I'm not disputing the fact that ABS on a motorcycle is effective & does lower some accident types (especially with new or inexperienced riders).

[pgm]

@dirtrider - my apologies that I couldn't provide the direct data, but only connect dots with the requirement of CHiP's (and other's) motorcycle fleet and an in-depth statistical report(s).   If I ever find the original report (data), I will send you a direct message.  It was a significant factor for me buying my R-bike in 2004. I can't believe the government (NTSB) is not requiring ABS on all motorcycles. 

 

The reports demonstrate ABS improves survivability (sp?) for all types of accidents, for all riders.  Not just "some".  All.

 

We are really far off topic from the "linked" I-ABS question of Redman.

[AndyS]

Hi PGM, if you ever have your iABS fail on you, you will change your viewpoint very quickly. I was riding some cliff edge bends when mine failed. I almost met my maker much soon than I expected. The residual braking is NOWHERE near as powerful as the normal braking and when it does happen it will effect you deeply! Dumping that system was the most confidence inspiring thing I ever did on my 1150RT.

I am not saying ABS is bad. It's not. However the one on the 1150RT is bad.

[pgm]

11 hours ago, Tri750 said:

After the first year of the R1100RT-P the bidding spec was updated again requiring ABS since that first year, there were no Motor fatalities from traffic accidents . 

Thank you for the detailed (and accurate) info. 

I could not find the original article & data to support my memory.

 

It is an interesting fact that it was added year 2 based on experience.

 

[dirtrider]

On 10/4/2019 at 3:12 PM, pgm said:

We are really far off topic from the "linked" I-ABS question of Redman.

 

[cat0020]

I'm in the process of removing the servo-assist-linked ABS from my 2002 R1150RS.

Thanks to dirtrider & AndyS for the pdf document on servo-ABS removal. 

 

I had a 2002 R1150RS back in 2003-2005, felt the servo-assist intrusive, drains battery unnecessarily, and never quite felt the need for ABS on any motorcycle I've owned. 

 

My current 2002 R1150RS was purchased cheap with ABS issues, I just decided to remove the unit completely, change out the 17 year old brake lines. 

 

For a bike from that era, repair or finding parts for that ABS unit is likely to be expensive, getting rid of servo-ABS pump would likely reduce some weight from the bike (up high). 

 

Brakes, who needs them; they only slow you down.