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Does TRAC engage while in reverse?

Discussion in 'Gen 2 Prius Main Forum' started by GreenMachine, Dec 1, 2005.

  1. GreenMachine

    GreenMachine New Member

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    My driveway is such that I have to back uphill to get out to the road (See my avatar -- that's Subaru on the left and a Honda Civic on the right)

    Will TRAC kick in and prevent me from getting out? Rocking forward is not an option normally.
     
  2. daniel

    daniel Cat Lovers Against the Bomb

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    My general experience is that traction control helps, rather than hinders, movement. When one tire spins it applies a brake to the other, allowing power to go to the tire that is not spinning. It also reduces the gas. Thus, at an icy intersection, when other cars are madly spinning their tires and going nowhere, I can floor the accelerator and the car says to itself, "Silly driver, that's too much gas." and gives it just the right amount of gas for the conditions, and my Prius moves ever so slowly (but faster than most of the other cars) through the intersection.

    But you probably want the best snow tires you can get.

    You cannot rock the car, but you cannot rock an automatic either.
     
  3. GreenMachine

    GreenMachine New Member

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    That sounds as if it will work perfectly for this situation Danny, thanks.

    I am gonna be getting Michelin X-Ice snows unless something changes my mind by January when I pick up the Prius. CU rates them at the top for traction in ice and snow as far as non-studded tires go and I don't want studs.
     
  4. GreenMachine

    GreenMachine New Member

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    Oops --- I still don't know if TRAC works when the car is in reverse? Since there isn't actually a reverse gear and the car uses the electric motor for reverse -- TRAC might not engage?
     
  5. finman

    finman Senior Member

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    yep, it works in reverse. Tried it yesterday on 2" of packed snow. punched it and sure enough I had a controlled backing up instead of the spinning tires with no steering control.
     
  6. GreenMachine

    GreenMachine New Member

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    Great! Thanks, just what I wanted to hear.
     
  7. jayman

    jayman Senior Member

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    Having bogged down on Winnipeg streets last winter during our blizzards - before my winter tires arrived - I will also positively state Trac engages in R.

    Proper winter tires make all the difference.
     
  8. KTPhil

    KTPhil Active Member

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    "When one tire spins it applies a brake to the other, allowing power to go to the tire that is not spinning."

    I don't think the Prius TC works this way. It seems to be more of an ICE-cutout than a limited slip diff or electronic braking control. It just cuts power for a second and then retries.

    My jaded opinion is this is a Microsoft-esque "it's not a bug, it's a feature" kind of marketing effort. They needed to limit wheelspin to protect the PSD, and call it TC to make it sound like a feature. And it's "free"! What a marketing trick!
     
  9. dufusone

    dufusone New Member

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    I believe that because of the way the planetary gear works, TRAC is more important in reverse to prevent overspin of MG1 than in drive.
     
  10. oly_57mpg

    oly_57mpg New Member

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    Just don't try to back up a steep icy slope. My house sits at the end of my very steep and short driveway. As I was backing up this morning in the 1-3 inches of snow, the TRAC engaged and stopped both front wheels from turning. Ok, fine, but there isn't anything else to grip to. Guess what, the car slid back down to the house. I came really close to taking out the garage door... I really wish there was a way to disable the traction control.
     
  11. GreenMachine

    GreenMachine New Member

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    Wow! That is exactly what I was worried about here. Do you have very good snow tires?
     
  12. tumbleweed

    tumbleweed Senior Member

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    Well actually there is and it's posted here. It's called Inspection Mode.

    http://priuschat.com/index.php?showtopic=6...ion%20mode&st=0

    It's on page 2 of this topic but I would suggest reading the whole topic before use use it. I think it would be easy to damage the PSD with TC disabled. I have tried it and it works but I was very careful with the car when I tested it.
     
  13. oly_57mpg

    oly_57mpg New Member

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    Nope. I have the stock OEM tires. I'll bet that I _could_ get better tires but for the two or three days that the weather might be bad... Or, I could just stay at home and not worry about it.