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Problem backing up a hill

Discussion in 'Gen 2 Prius Main Forum' started by greybeard, Sep 29, 2004.

  1. greybeard

    greybeard New Member

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    I found myself in trouble today when I pulled into a neighbors driveway and then tried to back out. Is their a problem backing up a hill? I put it in reverse, and it didn't move for a couple of seconds and then barely backed up his hilly driveway. I thought I was going to have to be towed or pushed out. Is this normal for the hybrid?
     
  2. V8Cobrakid

    V8Cobrakid Green Handyman

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    I'm sure you will eventualy look for the answer you are looking for. I have notices this too. The reverse on the car is electric only. It starts off slow no matter what. I've been able to back up my driveway but i was rolling beforhand. my driveway is probably about a 25-30 degree angle. i think i have the angle about right. hehe. anyways, the car will start out slow. It does this. Once going it gets quick. If it's on an incline it may stop itself from going "all out" because it doesn't want the electric motor to get damaged. The motor has almost 300 ft/lbs of torque. The same torque my HO 5.0L V8 had. It's capable of burning the tires but the system stops it. I learned this when driving on a gravel road.. hehe

    glad to hear you made it out of his driveway though. i don't think a driveway would stop it. I heard that it wont' back over a curb though. *shrug*

    I'm sure more will reply

    :mrgreen:
     
  3. peart75

    peart75 New Member

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    if i am correct, only the electric engine can be in gear when in reverse. i was wondering if this would ever become a problem if the battery was low, the grade was too steep, etc...

    certainly something to keep in mind.

    -drew
     
  4. HTMLSpinnr

    HTMLSpinnr Super Moderator
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    They say to crank the wheel and zig-zag up the hill if going straight up won't work.
     
  5. DaveG

    DaveG Member

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    Also, don't be afraid to floor the pedal in reverse if you need the power - I noticed that the classic had problems reversing up the incline (fairly steep) to my parking lot. It took much firmer pressure on the pedal than it did going forward to go up the hill.

    Once I pushed harder on the pedal, it moved OK (though I wouldn't wanna try it with a car full of passengers - probably best to park facing uphill then).

    Dave.
     
  6. TCD

    TCD Junior Member

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    Hi Folks,

    I actually had just the opposite problem in that I became stuck going forward up a steep gravel hill. I found that the traction control simply shuts down the power rather than driving the wheel with the most traction; this caused a real problem for me.

    The Prius came to a stop in the middle of the hill and I had a very tricky job of backing down! Each time I tried to go forward, the wheels would slip a little and then the power shutdown.

    I overcame this by driving from the bottom, up the hill much faster than I wanted (later I also backed up with no problem). I am concerned that this behavior of the traction control will prove to be a problem this winter. It certainly does not provide “traction controlâ€! I wonder if there is a way to by-pass the traction control?
     
  7. V8Cobrakid

    V8Cobrakid Green Handyman

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    Your experiance is the exact same as mine. As for winter, i test drove the prius a couple times. Dry weather test drives were fine. One time i test drove it in the rain. When getting onto the highway, i was wishing for actual traction control. You look speed when the car starts slipping. Again, this is because of the huge amount of torque when you first start to accelerate. I guess we have to just get a head start on anything slipery. Hey, doing high speeds on the dirt road was more than fun. The steering assist and traction control work better around 30mph. The car steers and moves like a charm. :mrgreen:
     
  8. V8Cobrakid

    V8Cobrakid Green Handyman

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    I also found the car does not slip while in soft dirt. it climbs like a champ. So.. i guess it's just hard surfaces it shuts down.
     
  9. jamarimutt

    jamarimutt New Member

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    My previous car, a 2002 GTI, had a switch to turn off traction control. The owner's book recommended leaving the control on all the time, but acknowledged that under some slippery conditions it should be turned off. My brother-in-law's 2004 Chrysler 300 has a similar on/off switch.
     
  10. randalla

    randalla Member

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    My '99 GrandAm GT also had an on/off switch for the traction control. Has anyone found a way to switch the Prius's traction control on/off yet?
     
  11. greybeard

    greybeard New Member

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    I'm not experiencing any wheel slippage. It's just that it backs up the driveway (hill) with so little power, I was afraid I would have to be pushed.
     
  12. HTMLSpinnr

    HTMLSpinnr Super Moderator
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    No way to disable the traction control. It's there to protect the PSD (power split device, planetary gearset) and to prevent MG1 (generator) from suddenly overspinning if spinning wheels were to suddenly slow and gain traction with a revving engine.

    Only one way to disable and it's with a mini-scanner, and it's temporary for purposes, emissions testing (dyno), spedometer testing, or any other test that would require the front wheels to turn independant of the rear.
     
  13. norman

    norman New Member

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    re: Reverse issues : electric only.

    I have done some extensive research and discussed with others who understand newton metres and etc etc. The reverse angle is limited to around 38% (not degrees), that is 38 rise / 100 distance in reverse, and 46 / 100 forwards. THis is very steep. Many rear wheel drive cars facing down an incline like this would just skid their wheels. I have attached a spreadsheet which helps you calculate the steepness. BTW, I searched for the steepest street in my neighbourhood. No problems backing up. We must really be talking STEEP!!
     
  14. KMO

    KMO Senior Member

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    I'm not totally convinced by that formula. It's mathematically correct, but simplistic, and assumes that the traction control systems actually allow full torque to be applied from a standstill. That's the primary problem - we don't know how the software limits the hardware.

    Other details: 478Nm isn't available forwards from a standstill - it'll be slightly less.

    Also, it could be worse in reverse if the battery is low; if the engine is running then some torque is applied in the wrong direction, reducing the output torque.

    Oh, and some rolling resistance should be added.

    Basically that formula gives an upper limit to what the Prius can achieve, but it may be less in practice.
     
  15. wetntacky

    wetntacky New Member

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    This traction issue concerns me alot. I have yet to experience my first Chicago winter with my 2003 Classic. Where I live I must enter a parking garage that has a ramp at about 35 degree incline on smooth concrete. You have to pull up onto the ramp at a dead stop to operate the keycard device to open the door. People in standard cars without sufficient weight have difficulties getting in without slipping and sliding. This could prove to be a major problem for me if the traction control device will not actually provide me with some traction. Anyone have any more input on this particular situation? From the dead stop I will be at, I must travel up about 20 feet before I reach the flat area of the garage.
     
  16. bruceha_2000

    bruceha_2000 Senior Member

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    Are they running snow tires? Will you be?

    I just got my car last week so I'll not see first hand until winter. I asked a friend who got hers last Nov if they used snow tires and she said "Don't know if was necessary, but we had them and the car handled FANTASTICALLY".
    I will have snow tires, it isn't reasonable to live here and not use them. Sure, MOST days they aren't needed, but when you need them, you need them (in my best Yogi Berra impersonation voice) :)

    A lot of people who run all weathers slip and slide all over the place, especially getting going from a stop, even on the flat. I suppose they might be passable when they are brand new but they just don't have the tread pattern to grip in snow. Nothing but chains or studs grip on ice.
     
  17. DaveinOlyWA

    DaveinOlyWA 3rd Time was Solariffic!!

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    38% grade!! OMG!!

    where you gonna see that??

    i had to do some research on this one and the steepest hill in Olympia is San Francisco street and it is closed anytime there is anything remotely resembling a freeze and its grade is 24% and it is STEEP.

    it is steep enough that rocks will not stay on the road.
    the reason why it was so steep was because of property disputes, switching back was not available.

    many people are familiar with Lombard Street in San Francisco. it is so steep that walking up the road is difficult on the curvy part. it is a 16% grade.

    the steepest street in San Francisco is Jones, 22nd and Filbert street at 29%...
     
  18. DaveinOlyWA

    DaveinOlyWA 3rd Time was Solariffic!!

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    some more steep stuff

    the 20 steepest streets in Seattle range from 21% to 18%... that surprised me ( that Olympia beat Seattle in something besides most politicians) as some of those streets are a real bear to stop in time for lights. i have skidded through countless stop lights before.

    keep in mind that 14 of these steep stretches are only one block long. a sustained slope like that would be extremely dangerous.
     
  19. DaveinOlyWA

    DaveinOlyWA 3rd Time was Solariffic!!

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    ok last thing on the subject of steepness.

    i guess if the 38% grade thing is correct then we have nothing to worry about since the steepest street in the world is Baldwin Street in New Zealand at a relatively flat 34%.