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Model X towing: ball hitch offset

Discussion in 'Model X' started by Padelford, Jul 22, 2017.

  1. Padelford

    Padelford Member

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    IMG_0581.JPG I've used my trailer towing option to pull a small U-Haul trailer fir a quick trip to IKEA. The U-Haul folks set me up with the attached ball hitch using the "rise" configuration. With this, the trailer was nearly perfectly level with the vehicle at standard height (which is what the manual calls out for towing).

    The Tesla manual says the ball offset is supposed to not exceed ¾" above the receiver. This ball hitch violates that but makes the trailer level, which it is supposed to be based on what I've read. So, am I incurring some risk to my vehicle using this ball hitch? If so, what do I do to get the trailer level with a smaller offset?
     
  2. McRat

    McRat Active Member

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    You need all kinds of offset hitches to haul trailers. Because not all trailer have the same tongue height. The potential issue of a high ball point, is that if the trailer has no brakes, and is heavy, a ball that is higher than the receiver will lift the rear of the vehicle under heavy braking which can cause a jacknife. This very unlikely. The other possibility is that there is a weakness in receiver when it come to lift, again, I find to be unlikely since lift happens anyways with the bumps in the road.
     
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  3. KarenRei

    KarenRei KarenRei KarenRei KarenRei KarenRei KarenRei

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    This talk about jackknifing makes me curious about something. I'm ordering a Model 3, and if they have a tow hitch option, I'll be getting it so that I can haul my trailer with it and get rid of my pickup. But one thing makes me concerned: several weeks ago, I accidentally forgot that I was hauling a trailer (it's not visible behind my truck with the tailgate up), backed up for something, jackknifed, and bent my rear fender (as well as requiring repairs on the trailer). Now, in my old beat-it-up pickup, that's not a big deal to take some damage, but in a new Model 3, that'd be tragic.

    Does Tesla have anything to prevent accidental jackknifing while backing up? If not, can you think of any good improvised solutions? Maybe taping on some empty aluminum cans so that there comes a crunching sound first? ;)
     
  4. Padelford

    Padelford Member

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    Ultimately, I want to understand the ¾" offset limit that Tesla puts in the owners manual.
     
  5. GoTslaGo

    GoTslaGo Learning Member

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    All the Teslas* so far have rear-view cameras which will show your trailer as you back up (although you cannot see behind the trailer itself). So typically you can eyeball your trailer position as you back up. Bjorn (Youtube fame) has a good amount of videos showing towing issues with the X. He even rigged a camera on the trailer to see behind it. Also, you may be able to use summon to do this as well...IIRC he did it somehow.

    I know @ohmman has been doing lot's of road-tripping towing an airstream, and has some impressive posts about it. You may want to check out some of his posts too (both OP and you).

    *I assume Model 3 will too.
     
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  6. jamtek

    jamtek Member

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    @Padelford I think you ask a legitimate question and have a legitimate concern. I have tried to delve into this myself. I have asked this very question to Tesla engineering but am still waiting for a response from them.

    The offset limit may be relevant to acceptable force loads placed on the factory hitch system. This may limit what hitch "add-ons" are safe with the factory hitch, such as weight-distribution/anti-sway systems. I contacted Bosal (maker of the Tesla factory hitch) and the response I received was that a WD hitch system "cannot be recommended." I am still waiting to hear back on the "why."

    There are several users who are active on this forum that are using WD systems with their Model X. Hopefully, they can chime in here. I intend to post what I learn here, FWIW.
     
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  7. ohmman

    ohmman Maximum Plaid Member

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    Tesla engineering is unlikely to answer. The question should really be posed to Bosal, as the limitation is theirs.

    I believe that @jamtek is correct. It has to do with the way that the offset changes how loads represent themselves in the system. In the case of the factory hitch, that offset is most relevant when it comes to the attachment point of the removable receiver. A higher offset increases strain on the receiver attachment. 3/4" represents the distance from the top of the receiver to the wedges that lock into the vehicle crossbar. As the tongue weight is pushed farther up, more torque is seen at the attachment point.

    There are probably some tolerances and one could put less weight at a higher offset safely, but I think Bosal has only tested for their recommended case.

    Leveling the trailer is a real challenge with the stock hitch. That's why I believe it really has a limited (but useful) range of applications, and if one is regularly towing, they should consider upgrading to an aftermarket hitch. That's what I did.
     
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  8. Padelford

    Padelford Member

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    Thanks for these replies. I'd like to know how Bjorn did his big tows with this restriction.

    I suspect that, for lightweight towing like Idid with the little U-haul trailer, the 2 ¼" offset may be OK but the ¾" rule really applies to multi-thousand-pound cases. In 20-20 hindsight, I could have raised the vehicle height above Standard to reduce the ball hitch offset needed to level the trailer.
     
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  9. BerTX

    BerTX Active Member

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    Ride height will automatically reduce as you speed up. You will drop from VH to H at about 15 mph, and from H to S at about 30 mph. YSMV.
     
  10. ohmman

    ohmman Maximum Plaid Member

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    Ride height will not adjust when towing. Tow mode disables that.
     
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  11. BerTX

    BerTX Active Member

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    I was not aware of this, thanks. So to clarify -- if you set it on Very High and drive at 55 mph, it stays set to VH? Or do you just mean it doesn't reset from Standard to Low?
     
  12. ohmman

    ohmman Maximum Plaid Member

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    #12 ohmman, Jul 24, 2017
    Last edited: Jul 24, 2017
    Thanks for asking. I believe I misinterpreted the way this worked, and your question made me research further. I believed it would set the suspension to standard regardless. This doesn't appear to be the case.

    As it turns out, Tesla has recently updated their towing section in the Model X manual. There is quite a bit of new data and I'm going to start a new thread, but as it pertains to the topic at hand, here's what they have to say about it:
    I think I conflated the two statements and assumed no height adjustments were made.

    Regarding whether or not one should use the air suspension to level the trailer, the answer is a clear "no":
    It's worth noting that they do tell you to set air suspension to "STANDARD" prior to hitching the trailer, so effectively what I assumed happened automatically really will be the outcome. There just doesn't appear to be anything stopping it from staying on HIGH or EXTRA HIGH.
     
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  13. Padelford

    Padelford Member

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    "You must choose a trailer hitch and trailer that have the appropriate height for suitable axle loading and trailer balance" subject to the +/- 3/4" offset restriction.

    So it goes.
     
  14. ohmman

    ohmman Maximum Plaid Member

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    Actually, + only. No drop is permissible.
     

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