K11 Owners Group

[Flying Duck]

I use the term false positive to refer to a siuation where the ABS kicks in when it shouldn't/isn't needed.

ABS II false positive scenarios I've found:

Angular crest in the road: There's an uphill stop sign on a street that I use every time I leave the house. There's an angular crest(where the concrete slabs meet) in the street about ten-fifteen feet before the stop line. Virtually every time I come to this stop, the rear modulator will release the rear brake for a split second - adding maybe 5 feet to my expected stopping distance. I know that this isn't something wrong with MY ABS as the ABS in my brother's 2001 525i will often get fooled by the very same hill.

Here's a profile of what the street looks like:



Braking into a pothole: In this siutation, the front will release for a split second. This doesn't happen every time I brake into a pothole but it does happen. Again, I can also have this happen in my brother's car so I don't think it's something unique to MY bike or even the ABS II system.

Lane-splitting: Sometimes the rear releases when braking on road nipples while lane-splitting. Others here have reported this one too. It's a minor annoyance but it does happen relatively often. When I figure out how to lane-split in a 525i I'll see if I can replicate this one in my brother's car.


ABS I false positive scenarios:

None.

Between the LT and the K100RS4V I had, I've got 35-40k on ABS I bikes vs. about 9k on the ABS II RS. In all that riding I don't recall the ABS I ever producing a false positive - even on the very same hill described above which I've ridden a zillion times.

My theory is that ABS I has a longer cycle interval than ABS II and that the anomolous scenarios above are of such short duration that they don't register in the ABS I brain.

CONCLUSION: Given the above and that spline lubes are easier on an ABS I bike, I kind of prefer ABS I over ABS II.

Footnote: I've only had ABS kick in once when I actually needed it. I was on the LT on an onramp. I was doing a left shoulder check of the traffic I was about to merge into. When I turned back around, the pickup truck in front of me had slammed on it's brakes. Given my momentum and available reaction time,(and following too closely ) swerving around the truck was not an option. Knowing I had ABS, I slammed on both brakes. CHUNK, CHUNK, CHUNK went the ABS I. I came up about a foot short of the truck's bumper. Without ABS, I suspect that I would've locked the rear a bit and ended up kissing the truck's bumper.
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93 LT (x2)
94 RS
86-97 K75F(K75/100/1100 Frankenbrick)
86 K75C w/paralever, hi perf cams,TURBO!
91 & 92 K75Ss
91 K1
86 custom K100
14 WR250R
IBA #17739 (SS1K, BBG, 50CC)
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[Scott_Anderson]

I know it's not exactly the same system, but, I have had similar "releases" of the brakes on my pickup. (3/4 ton with trailer tow suspension & 8ply tires)
Any slight bounce that would cause the wheels to rotate at any different rate causes it to release. Potholes, slab joints, speed bumps, deep rumble strips. The more I have the truck loaded the less it happens obviously.
But it's just anoying.
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Ride safe.



1995 K1100LT 0302044
2017 FLHTK Ultra Limited
Garmin StreetPilot 2820
Garmin Zumo 550
Garmin Zumo XT
"One who does not ask questions is ashamed to learn" Danish proverb
1997 K1100LT 0302488(R.I.P.)
1997 R1100RT ZC62149(sold)