Re: BMW brakes in the news

[rene-didier@xxxxxxxxxxx]

I have a R1100S with ABS. After a motorcycle safety course I took a few weeks ago, I am even more convincened ABS is well worth it. We had to practice HARD stops. Yes, it chattered both front and rear. Most others were locking up the rear wheel, some the front. The ABS allowed me the fasted speeds thru the trap, and some very short stoping distances. It will also do "stoppies". I don't use the ABS every time I stop. It would make for some pretty brutal stops. 

After the class, the instructor came up to me and said that he was impresses with the ABS, and would pay the extra on his next bike, if available, just for the extra safety margin.

The top 3% of riders may not need ABS. I'm not in that group.When I need ABS, I am happy to have it.

- -Rene
02 R1100S

- -------------- Original message -------------- 

> Hello all, 
> 
> John Dancoe wrote: 
> 
> > According to the report, BMW's argument is that "...brake failure...only 
> > occurred under very specific circumstances..." 
> [...] 
> > However, the failure which I experienced multiple times was what I would 
> > describe as ABS "chatter" which resulted in me "holding down the brake 
> > lever 
> > as hard as I could but the bike just kept going", and the "very specific 
> > circumstances" were nothing more than bumpy pavement...of which there is 
> > plenty in Michigan. 
> > 
> > But "insufficient electricity due to overuse of the handbraking 
> > mechanism"??? 
> [...] 
> > All that said, I credit BMW for trying to improve motorcycle safety. For 
> > many 
> > riders, especially inexperienced ones, it is surely a good thing. It just 
> > didn't work for me personally; I feel more strongly than ever that 
> > removing 
> > the ABS is the best thing by far that I've ever done to the bike. 
> [...] 
> 
> For those who are interested, the Big List is running like a rabid dog with 
> speculation about (a) the precise nature of the reported problem (as you 
> know, the 'Net article was vague and did describe the symptoms or 
> circumstances), and (b) what was meant by BMW's response. Loads of 
> speculation. No facts. 
> 
> Interestingly, one list member speculated that a rider *may* have operated 
> the power-assisted-brake bike with the ignition key on, and the engine off, 
> for an extended period of time. This could result in a scenario in which the 
> battery was run down (because the engine is not running and therefore not 
> charging it), and at some point, the power-assist would stop working on the 
> brakes, and this may possibly cause the operator to be surprised. Also 
> written on the list is the observation that if BMW's response was in German, 
> as one would expect from BMW Corporate, then a few sentences taken out of 
> the context of a thorough response, and then translated from German to 
> English, it could result in something that appeared to not "hold water." 
> Again, I stress this is ALL conjecture, as the article provides little facts 
> other than someone has a problem and they believe BMW's brakes are at fault, 
> and BMW doesn't agree. 
> 
> With respect to John Dancoe's ABS observations, yes, BMW bike ABS responds 
> suboptimally under some real-world conditions. One such scenario occurs on 
> level road at moderate speed (say 40 mph), and applying brakes moderately, 
> say 1/2 (?) but not near threshold of locking. The rider can gauge when the 
> vehicle will stop under these conditions. However, if a wheel encounters a 
> significant pavement irregularity such as a sudden dip (sunken man hole 
> cover, or the location *after* a significant elevated bump), the ABS senses 
> momentary loss of traction and believes lockup is imminent, and therefore 
> pulses the brakes momentarily. To the unsuspecting rider, this feels like 
> the brakes released momentarily (because they did), and therefore increased 
> stopping distance. This situation is aggravated if a series of such 
> irregularities are encountered, thereby reinitializing the ABS cycling, 
> and/or if the rider is going down a steep hill, in which case gravity is 
> acting as an added accelerator. 
> 
> BMW's ABS does not fare well under these conditions, and it is best for the 
> rider of an ABS-equipped bike to be aware of these limitations, and to ride 
> accordingly. 
> 
> -Steve Makohin 
> '01 R1100S/ABS 
> Oakville, Ontario, Canada 

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