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Model X Brake Hold While on Incline Works Differently Than ICE

Discussion in 'Model X' started by mswlogo, Jun 30, 2020.

  1. mswlogo

    mswlogo Well-Known Member

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    Well I thought the X was a great tow vehicle until this summer when I’ve had to back up a trailer up a hill several times.

    An absolute dangerous train wreck. In fact one situation I had to give up.

    I was in Hold mode and tried switching to Creep which helps a little.

    When stopped on a hill with a trailer headed up hill, as soon as you take your foot off the brake the car starts rolling down the hill. I try to get my foot on the throttle as quick as possible but it’s not enough. Even with throttle fully down it’s still rolling forward down the hill. Then it figures out I want to go in reverse and starts to zing up the hill to fast. Trailer ends up not where I want it. Rinse and Repeat over and over.

    This was with a 1500 lb trailer.

    I’ve towed the same hill with 4500lbs trailer with ICE (Jeep) no problem. With ICE you drive TWO FOOTED. You bring the throttle up BEFORE you let the brake go. Then you just let up on the brake and smoothly go up. You can’t do this with the Model X.

    This could be fixed with software with a tow mode. But right now, if anyone asks I’m saying don’t even think about towing. You never know when you might need to tow backwards up a hill.

    I just got a new property on a lake with a hilly driveway. If I want a boat I will need a new vehicle.

    I’ve been towing for 40 years. Including with 2WD *sugar* boxes. Nothing has come close to this poor or dangerous for backing up a trailer of any size.

    Buyer beware.
     
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  2. njhtran

    njhtran Member

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    how is it for towing other than backing up a hill?
     
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  3. Saghost

    Saghost Well-Known Member

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    I’m confused by your experience.

    Normally, from a stop the car holds on to the brakes until I hit the accelerator, vehicle hold engaged regardless of creep setting.

    Was that not happening? Or were the brakes not being held firmly enough to stop the trailer?
     
  4. mswlogo

    mswlogo Well-Known Member

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    Great
     
  5. mswlogo

    mswlogo Well-Known Member

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    That’s a valid question. I had not thought about it. The car works fine in Creep or Hold with no trailer (forward or backward going up a hill). But it is rolling forward when backing up with the added weight (and not that much). I forget if it is rolling when letting go of the brake or the moment you touch the throttle (before you have enough throttle to overcome the the extra wait). I need to tow more today, moving. I’ll double check what’s happening. Might try unplugging the trailer and see if it behaves different out of “tow mode”. I’ll double check with no trailer too.

    What ever it’s doing it’s terrible.

    2029.24.6.1 LR Raven
     
  6. ShawnA

    ShawnA Supporting Member

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    Hi Mswlogo,

    Do you have electric or hydraulic brakes on the trailer???
    The load is pretty "light" for additional brakes but they could help
    in this situation.

    Shawn
     
  7. Plan B

    Plan B Active Member

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    lmao
     
  8. wooter

    wooter Nou ik heb niet te klagen over Tesla support

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  9. mswlogo

    mswlogo Well-Known Member

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    I have hydraulic surge brakes on one trailer and MUST be disabled when backing up. There is a locking pin just for that purpose. Otherwise they would engage when backing up. Especially a hill. I have forgotten to put the pin in on the Jeep and the trailer brakes work perfect and I could not over power it. ;)

    I have Another light duty trailer that has nothing. This is the one I was using recently.

    Another trailer that has electric brake controller. The brake controllers sense deceleration to engage brakes. They would not apply backing up slowly.

    So in all 3 cases they would NOT help.
     
  10. mswlogo

    mswlogo Well-Known Member

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    Hold mode should automatically activate when I’m when stopped in Hold mode. Creep actually worked better.

    When backing up a trailer up a steep hill you kinda of “ride the throttle”. You let up it goes down, you give a little gas to hold and more gas to go up. I think the car starts rolling down to fast as soon as hold releases. You have to give it a lot of throttle and there is to much lag if the car is move the opposite direction.

    On the Model 3 if you flip direction opposite of motion it bites and responds quick. I notice on Model X there is huge lag. This lag is causing the problem.

    Try it even with no trailer. Backup about 2mph and flip it to drive and step on throttle. You’ll starting moving forward after a very long delay. It’s fine if fully stopped. But when your backing up you don’t full stop every 3 feet. You ride the throttle.
     
  11. MP3Mike

    MP3Mike Well-Known Member

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    Have you reported the issue to Tesla?

    I suspect that some of this will improve with software updates, but it may not come until after the release of the Cybertruck when they get serious on towing. (Though I would think they might have some experience now with the Tesla Semi.)
     
  12. Yinn

    Yinn Active Member

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    Admittedly, my initial reaction was BS. But these two statements stuck out to me. Creep handles most of my going backwards issues - but not if I'm loaded up to 5000lbs on a hill. In those situations, I've done as you stated - I two footed it.

    But...I haven't done it since the software change to disable acceleration when both pedals are pressed. That software change was to address unintended acceleration, but it may have actually been harmful for towing in this exact situation.

    The only other thing I can think of is to use the hill hold and chill mode, which is probably why I haven't two footed it. I currently have a drivers profile called "Towing" in which it moves my mirrors our, enables creep, and enables chill mode so I don't have to toggle them individually. When I'm using chill, I let the hill hold work while I'm fully stopped. When I go, I can mash the pedal harder than normal and let chill mode prevent me from lurching, upsetting the load, and putting unnecessary stress on the car from the instant torque. It essentially takes the need to feather the pedal away.

    Not sure if it'll solve it on your particular situation, but might be worth a try.
     
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  13. Uncle Paul

    Uncle Paul Well-Known Member

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    Agree. Issue might be something that Tesla has not experienced, and will need some new software to rectify.

    Backing up a hill might be one of those edge cases that never came up in development.
     
  14. ShawnA

    ShawnA Supporting Member

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    Hi Mswlogo,

    Thank you for your reply.
    Hydraulic brakes would definitely be bad without the lockout pin...

    I have mostly used electric brakes with various Tekonsha controllers.
    Most of them have a manual switch where you can brake on demand.
    Sometimes it is used briefly to stabilize a swaying trailer.

    It would be awkward but in your case it could be used to hold the trailer
    while you are preparing for your next maneuver...

    Just a thought...

    Shawn
     
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  15. wooter

    wooter Nou ik heb niet te klagen over Tesla support

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    Sorry but I don't have that experience, and I back up on a hill every day to my garage. I can ride the throttle, but I can also engage hold, and from hold I can touch the pedal to start moving backwards.

    I always use creep mode. I find it gives me more of a fine-tuned control when manoeuvring. But this means I also have to explicitly put the car in hold mode, by pressing the brake pedal harder than normal.
     
  16. shikk

    shikk Member

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    Sorry you had a bad experience. Like @wooter I back up into a steep driveway every day and did find it took some getting used to because i have it sent to automatically stop and hold and it seems to get confused when I'm trying to ride the throttle. My experience is the same as his, I know for a fact that you can go from a "hold" to a state to where you are riding the throttle and a little input will allow you to reverse. As others have alluded to, you want to keep the car in (H), then just press on the gas just enough to release the hold and maintain your position, then hit the gas harder to reverse. It's no different to me than two footing it or using a parking brake with a manual when reversing up a hill, have plenty of experience with that and this is actually much easier.

    I tow a 3500lb trailer and on my second time out had to do a 3 point turn from a narrow street up a sloped driveway. Not only did the X handle the reversing well, it saved my rear (literally) by allowing me to raise the suspension enough to let the WD hitch arms clear the end of the driveway where I had to turn. Trailer has electric brakes and I'm using the Tekonsha P3. I find that regen/hold does not actually apply any brake voltage unless I press on the brake predal, I try to just let it regen to stop as much as possible.

    Will be posting more on my experience with the trailer soon. Hope that helps. First post from a long time lurker.
     

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  17. scottf200

    scottf200 Active Member

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    I've done this press harder/deeper on the brake to go in (H)old mode dozens of times at stoplights in the past (before stoplight support and if I was 1st in line). You definitely don't need to press twice.
     
  18. RedXowner

    RedXowner Member

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    Without reading all the posts, I had to post this about using a trailer. I haul my boat at least 2 days a week every week. It took a couple times, but now I understand exactly how it's supposed to work. No need to ever race your foot off the brake and onto the accelerator. Unsafe and unnecessary. When you're on an incline or decline in a certain gear (reverse or drive), hold the brake down with your foot in the gear you wish to use next. The automatic brake will lock the car in place IN THAT GEAR so that you can slowly and safely take your foot off the brake and move to the accelerator. When you're ready to move the car and trailer, simply press the accelerator. Just make sure you press it hard enough so the car actually goes in the desired direction and doesn't roll the wrong way. The car is engineered to tow a trailer, and it works exactly as designed. But you have to understand how it works and take the actions above so your car doesn't inadvertently roll in an unsafe direction when taking off from a stop. This exact sequence has to be completed every time I launch my boat; otherwise, my car would wind up in the river.
     
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  19. mswlogo

    mswlogo Well-Known Member

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    Who the hell changed the subject. Well I guess the subject is right. Because it doesn’t work.

    No, hold mode DOES not cover it.

    As soon as hold mode is off if your backing up a STEEP incline you ride the throttle. You never touch the brake again. The balance is wrong when towing backwards up a steep incline. Works fine when not towing or a modest incline.

    I don’t go back to the brake on ICE and you don’t keep jumping in and out of hold mode. It’s fine for the initial move but once your moving you let up on the throttle and starts rolling the wrong way. And it takes to long to recover.
     
  20. RedXowner

    RedXowner Member

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    Prior to getting my MX, I have only owned manual transmission pickups, and I still own one. With a manual trans, you always drive two-footed, but the left foot is 100% for the clutch. I never used the left foot for the brake, especially whenever backing a trailer. Right foot for accelerator and brake 100% of the time. One one occasion, my daughter was towing her horse trailer and pulled the trailer down the hill of my driveway and parked at the house. So the task was now to back the horse trailer UP the driveway to exit. I did it for her when she asked. Every time I would let off the gas to adjust as I was backing uphill, I would have to let off the gas with right foot and depress the clutch with left foot and depress the brake with right foot simultaneously to keep the truck and trailer from rolling forwards. But then taking off from that stop with a manual trans - that's the real challenge. Let right foot off brake, press accelerator kind of a lot while simultaneously letting out the clutch to start moving the rig without stalling and without unintentionally rolling forward - fun stuff. The Tesla eliminates that challenge by allowing the brake to lock for you whenever you stop to adjust. Seems to me as if that would make it easier than the task I had, not harder. MX has tremendous towing power, so you're never challenged to make the car and trailer move, regardless of how steep the hill is. From what you're describing, sounds like the challenge is applying the correct pressure to the accelerator while backing up the hill. My guess is this will get easier as you back up that hill several more times. Like everything in life, there's a trick to it. Once you learn the trick, you're golden.
     

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