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Abs

Discussion in 'Gen 2 Prius Technical Discussion' started by FirstFlight, Apr 12, 2011.

  1. FirstFlight

    FirstFlight Member

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    I hate it. Is there anyway to disable it?
     
    #1 FirstFlight, Apr 12, 2011
  2. uart

    uart Senior Member

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    Yep. Don't brake so hard. :p
     
    #2 uart, Apr 12, 2011
  3. FirstFlight

    FirstFlight Member

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    That's the thing, I really don't. Even if lightly braking over a pothole, manhole cover, leaf or whatever, the damn thing releases the brakes and makes my braking distance much longer.

    I've had four other cars with ABS and none were even remotely close to the Prius.
     
    #3 FirstFlight, Apr 12, 2011
  4. uart

    uart Senior Member

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    Oh you mean the pothole thing. Yeah that's something that a lot of people have a problem with. I must be lucky though, or not enough potholes or something, because I don't notice it much.

    Anyway, they say that is caused by the switching from regenerative braking to conventional friction braking with apparently a small delay in the switching. The reason for the switching is because the regenerative braking can't do abs, so it has to switch over to friction braking.
     
    #4 uart, Apr 12, 2011
  5. FirstFlight

    FirstFlight Member

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    Ok, so maybe it's justifiable in that sense but it still sucks! This is one area where I miss my VW Jetta. Handling was a lot better.....
     
    #5 FirstFlight, Apr 12, 2011
  6. uart

    uart Senior Member

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    Yeah it's actually worse when you're only braking lightly. Because then it's initially only using regenerative braking. If you're really braking hard already when you hit the pot hole (or railway line etc) then the switch over doesn't happen because it's already doing friction braking.

    Anyway what happens is this, when you hit the pothole or some other rough patch the abs system senses the wheels turn at different rates and switches from full regenerative braking to full friction braking and this gives some kind of discontinuity in braking force.

    Maybe this discontinuity is worse on some cars than others. Some people really complain about it and other don't seem to notice it.
     
    #6 uart, Apr 12, 2011
  7. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Sounds like your car needs new tires. What tires are currently installed and what is the tread depth?
     
    #7 Patrick Wong, Apr 12, 2011
  8. FirstFlight

    FirstFlight Member

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    They are running a little low but I don't know the exact tread depth. Still seems weird that even with the tires as they are, the car slides as much as it does.

    The problem is that the ABS kicks in and there is a delay in allowing you to control the car again. Even if my tires were brand new, this would still be an issue. Yes, older tires may make you slide more but even with new tires you can still slide. If I was to slide for a split second, it seems like there is a loss in braking for longer than there should be.

    So as I understand it, there are two scenarios:

    1. Light braking with a slide - Going from regen to nothing will seem like a slide I suppose. I'll keep a better eye on this to see if it happens in the future but I know for sure that going over a pothole while braking lightly will cause my car to appear as if it is sliding.

    2. Braking hard with a slide - This is different from the above as the ABS kicks in. No question the ABS in the Prius will make your stopping distance longer. I've lived in the same area for the past four years. My VW Jetta would almost never slide, even in the worst driving conditions.

    Other than disabling it, the two things I can think of is to get better tires and increase the distance between me and the next car. However, there are times when I need to stop short and that doesn't give me a good feeling with the Prius.

    Truthfully I feel like I can control the car better without ABS than with it.
     
    #8 FirstFlight, Apr 12, 2011
  9. Patrick Wong

    Patrick Wong DIY Enthusiast

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    It is not possible to disable the ABS. If you buy a set of decent tires, I think you will be much happier with the car's handling and ability to stop short.
     
    #9 Patrick Wong, Apr 12, 2011
  10. FirstFlight

    FirstFlight Member

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    I hope you're right.
     
    #10 FirstFlight, Apr 12, 2011
  11. Patrick Wong

    Patrick Wong DIY Enthusiast

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    If your car is equipped with Goodyear Integrity tires, which are original equipment, don't underestimate how bad they are.
     
    #11 Patrick Wong, Apr 12, 2011
  12. hill

    hill High Fiber Member

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    When it comes to bad tires, Integrities take the cake. We switched to Michelins, and they're EXCELENT
     
    #12 hill, Apr 12, 2011
  13. Econ

    Econ Member

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    Fortunately, my v came from the factory with Michelin . They are 17"
    All of my cars have Michelin tires. Simply the best.
     
    #13 Econ, Apr 12, 2011
  14. cwerdna

    cwerdna Senior Member

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    #14 cwerdna, Apr 12, 2011
  15. FirstFlight

    FirstFlight Member

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    Patrick - I checked tonight and they are in fact the Integrity tires. The local Goodyear tire shop will install new fuel max tires for $470 plus tax. That is the cheapest I could find.
     
    #15 FirstFlight, Apr 13, 2011
  16. FirstFlight

    FirstFlight Member

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    By the way, the 195's are $10 more per tire than the 185's. Not sure if that's worth it or not. Any suggestions?
     
    #16 FirstFlight, Apr 13, 2011
  17. uart

    uart Senior Member

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    Are you looking at 195/60 or 195/65?

    The 60's will be the closest in height to the stock tires and therefore the most similar for speedo/odo readings.

    The 65's will be a little taller and will slightly reduce your wheel arch clearance. On the plus side they will correct the speedo which always reads slightly under speed on new cars.

    BTW, 195/60 is the stock tire size on many overseas models (including Australia and UK).
     
    #17 uart, Apr 14, 2011
  18. FirstFlight

    FirstFlight Member

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    I was looking at the 195 65 tires.
     
    #18 FirstFlight, Apr 14, 2011
  19. FirstFlight

    FirstFlight Member

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    So I have my new tires. I went over the same spot as I did before with the stock Integrity tires. Same result.

    The Prius is horrible when you are regenerative braking and going over a pothole, bumb or anything else similar. You lose all braking (unless you jam on the friction brakes) for about a second before it comes back on.

    This is my only "con" with the Prius so far. I guess you have to take the good with the bad.
     
    #19 FirstFlight, Apr 27, 2011
  20. wick1ert

    wick1ert Senior Member

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    I've gone over a couple spots the stock AVIDs used to help produce this. With the Michelin's on the car now, I haven't had it happen. Of course, I had the ECU update done on my car before I switched tires. A non-LRR tire will help minimize the effect, but you'll take a hit on the MPG also.
     
    #20 wick1ert, Apr 27, 2011
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