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Over zealous ABS

Discussion in 'Technical and Troubleshooting Torque' started by starling_bird, Dec 17, 2012.

  1. Riding my 2010 V-Strom to work today, I got to the first set of lights and tried to pull up behind the car stopped there, but the ABS on the front brake kicked in and I may have well have been on rails as I coasted into the back of the car. After exchanging details (bike left running) I tested the brakes a few times then rode to work with it behaving perfectly. Why did this happen?!
    It was dry asphalt and I was going slow with plenty of stopping room. The ABS should not have done anything. It often kicks in on the back brake when I'm down-shifting, and settles within a second, but I've never had it act on the front brake in the month I've owned this bike. Only thing I can think of is that the ABS reacted to a bump in the road or something and ended up being self-perpetuating for a few seconds. It's a very flimsy explanation and I'd like a better one if anyone can shed some light.

  2. Am I getting this straight - your ABS caused you to NOT stop in time (extended your stopping distance)?
  3. Wow! I never heard of that happening. I will interested to see the replies.
    I would hate that to happen on a corner.
  4. I agree, that sounds like a pretty serious malfunction to me; from what you report the brakes didn't work at all? That doesn't sound like an ABS-specific problem.....
  5. had this happen on my car... i dont like ABS 90% of the time.

    anyway my best guess would be you didn't lock the front brake but maybe grabbed it a little hard and lifted the back wheel without braking on it. The computer would see a speed differential where the front wheel was going slower than the back and ease off the front brake to try and get them to match...... bang.

    the opposite happens when you lock the back downshifting. the back wheel goes slower than the front and the computer eases the back brake to let it grip again....

    if it's not that then it could be a faulty sensor that the computer thought was functioning properly. if it didn't pick up that the front wheel was turning but the rear was then it would act as if it locked.... this is the issue i had with my car.

    edit: your bike may have an additional yaw sensor to detect whether the back wheel has come up and that could also be faulty.
  6. sorry to hear your woes!! I had similar thing happen when i had a bmw r1100rt once in the dry and once in the wet, abs didnt work and i could not stop, so after that incident i turned the abs off, worked most of the time but wasnt prepared to take the risk. ALSO had the dealership look and test the ABS system and no faults but they admitted there software was as good as useless- coming from a bmw master technician!
  7. Exactly. The brake did work, but not as expected. I only grabbed a small bit of brake, certainly didn't lift the back wheel. And I felt the ABS in the leaver, and the front brake did the on/off/on/off thing.
  8. You most likely don't even want to touch the breaks in a corner.
    If you do it, you are either a very skilled rider or going to crash next second :)
  9. #9 dima, Dec 17, 2012
    Last edited: Dec 17, 2012
    Did you think that you could have been a bit too eager with the breaks and shifting?

    The front ABS could kick in if you had grabbed the lever.
    The rear ABS could kick in when downshifting if the RPMs were too high (so you are basically mini-locking the rear wheel). ABS could be confused since you have the rear break on and "mini" locked wheel caused by the downshifting.

    That's the only reasonable explanation (apart from faulty unit) I can think of.

    But I would probably go to dealer and double check it because it sounds pretty strange.
  10. I have had the exact same thing happen in the car, and nearly drove through the storefront of the salvos when dropping off some stuff for christmas last year. Took the car in, and they identified a fault abs wheel speed sensor. It was sending lock up signals when there was no lock up, causing the abs to release the brakes.

    Get it checked out, you might have some build up around the sensor causing it to give a bad signal. I would just be having it replaced all together as a precaution.
  11. I'm leaning towards the theory that ABS has cut in as I grabbed the brake, then I grabbed a whole lot more brake to compensate. ABS kicks in again, and due to low speed, front suspension unloads before I get brakes back. Rinse and repeat. I could probably do the same thing 100 times and not get it to happen again.

  12. This sounds the most likely.
  13. That sounds like bs. Get it checked
  14. Hi
    when you say 'grabbed' were you startled when you needed to stop behind the car?

    um not sure that question makes sense ... what I am asking is >> were you caught napping and needed to e-brake?
  15. This doesn't seem correct. Rear wheel ABS releases the rear brake to help prevent it locking. I haven't heard of any systems that will release the front because of that the back is doing.
  16. No, I was surprised when the bike didn't slow as expected. Before that it was all very routine. After that I probably grabbed the brakes pretty hard, by automatic reactions.
  17. Similar problem from another forum http://goo.gl/PefRf
    But his was repeatable. My bike is clean, but previous owner took it around Australia, so sensor could be dirty/loose.
    I think pulling the ABS fuse for the ride home this afternoon would be good, and some spanner work when I get home.
  18. Well I'd be taking it in to Suzuki and having it checked ... if they fail to find any errors then perhaps get an instructor to review your braking practices ... this is a new bike to you isn't it? so is it the first bike you have ridden with ABS? Sometimes new technologies can highlight a technique issue.
  19. Worth getting it checked out, but not many problems would get past the computer, so I doubt they'll find the answer.
    Don't think there's a technique issue. I haven't locked a front brake in years.
  20. If there is a fault in the system a warning light should light up on the dash.

    Have you ridden with ABS before? Have you, 'tested' the ABS on this bike to see how it operates?