Rear overhang length?

Discussion in 'The Beginner' started by White Rose, Oct 15, 2009.

  1. White Rose

    White Rose Read Only Funster

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    This may well be a thoroughly dim question and I reckon the answer probably lies somewhere back in the recesses of my maths memory ... When we buy our motorhome, it will be stored at my dad's - how can I figure out whether I can get a MH onto his drive without grounding the rear end.... In order to park there, I need to drive down a steep hill, wide enough for two cars to pass but no more, then make a steep and fairly sharp uphill left turn onto his lane. Is there any way of working it out what the maximum rear overhang could be?

    I know twenty-odd years ago he used to take the caravan on there with the aid of a couple of planks of wood to level out the angles but I'd prefer not to have to resort to that after every trip out ...!
     
  2. The Wallace

    The Wallace Read Only Funster

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    It's not just the length of the overhang you have to worry about in that situation but the ground clearance at that overhang - some vans are lower than others. Every van is different so you more or less have to measure up the van you are considering.
    There is a thread somewhere about a guy who creased the side panels of his van because his towbar grounded.
    Remember to err on the safe side - when you see an empty van then that is the best clearance it will ever have - start to fill water, toys and people and that clearance will reduce instantly.
    Some people fit extra Air suspension units which allow you to 'pump up' your ride height and therefore increase clearance - but they are not cheap.
     
  3. scotjimland

    scotjimland Funster Life Member

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    Hi

    What you refer to is called the departure angle..

    Here are some examples....

    [​IMG]

    First thing to do is measure the angle of the the drive.. if it is greater than the departure angle of the proposed vehicle, it will ground.


    Bear in mind what the previous poster said about loading

    hth

    jim

    Edit

    If you Google ' angle measuring tool' there are some reasonably cheap ones, basically a folding ruler with degrees marked at the hinge with a spirit level built in ...
     
    Last edited: Oct 15, 2009
  4. vindiboy

    vindiboy Funster

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    Physics , don't ya just love it .:Rofl1::Rofl1::Rofl1::Rofl1::Eeek::Eeek::Eeek:
     
  5. zaskar

    zaskar Funster

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    ...............and if you want to know how to work out the ground slope, have a look at the attachment which i've (hopefully) added!:Wink:
     
  6. scotjimland

    scotjimland Funster Life Member

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    Nice one mate ... :Laughing:
     
  7. White Rose

    White Rose Read Only Funster

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    Nope, not even a little bit :Angry::Angry::Angry: :cry::cry:

    Well I might, if I hadn't abandoned it with a yell of relief at 14! Along with algebra, which i suspect is also coming into play here - no wonder it's making my head hurt!

    Looking at those pictures, I suspect I'm going to have an insurmountable problem - 9 or 10 degrees is nothing compared to the angle of the hill or the angle of the drive alone, and putting the two of them together makes rather a sharp V .... hmmm
     
  8. White Rose

    White Rose Read Only Funster

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    Thank you! That needs a cup of tea to digest it with ... hang on ... :BigGrin:
     
  9. scotjimland

    scotjimland Funster Life Member

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    Hi

    Have you considered a panel van conversion rather than a coach built ?

    A short wheel base Ford or Fiat van would have a greater departure angle ..

    failing that... a Unimog expedition camper (pic 4) :Eeek:

    jim
     
  10. The Wallace

    The Wallace Read Only Funster

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    Like your style White Rose but a glass of something is even better!
     
  11. White Rose

    White Rose Read Only Funster

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    Zaskar - I think I get that ... but I think my complicating factor is that my ground line won't be straight, if you see what I mean - if my back wheels are still coming down the hill as my front wheels are going up the next one, isn't that going to play havoc with my calculations ...? Sorry - I've no idea here, can you tell :Blush:
     
  12. White Rose

    White Rose Read Only Funster

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    I'm supposed to be at work, dontcha know :Rofl1: i'm going to be playing catch-up at midnight after this bit of skiving!
     
  13. White Rose

    White Rose Read Only Funster

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    Oh, is that what the last one is? It's a funky bit of kit, isn't it!

    Yep, perhaps I'm going to have to have a re-think about storage (or just move house ourselves!). Our plans were for something six berth - hence the appeal of coachbuilt.
     
  14. zaskar

    zaskar Funster

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    Ahhhhh.......errrrrrrrrrr, double OUCH!!!!!!:Doh:
    You're into what effectivly amounts to a compound curve there and really, the only way to sort that out (short of resurecting Einstien!) is to lay it out on CAD.

    edit =
    actually, thinking on, it's not THAT bad, well not from the calculation point of view anyway, but you (or possibly I) would needfull dimensions of where each "part" of the slope began and ended ( on the "double" slope side) and you'd also have to perform the same calc on the opposite slope as well. That way, you can add the "upward" angle of the opposite slope to the angle of the slope you're coming down!
    TBH, from what you've described, I'd hazard a gues and say you're stuffed! :-(
    J.C.B anyone? :)
     
    Last edited: Oct 15, 2009
  15. scotjimland

    scotjimland Funster Life Member

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    nowt wrong with a nice compound curve :Cool: :Wink:
     
  16. White Rose

    White Rose Read Only Funster

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    Um, to be honest, I have a sneaking feeling I'd find it easier to resurrect Einstein :Rofl1: :Rofl1: (I do like this little laughing man, but he does remind me of Peppa Pig's family all flinging themselves to the floor to laugh - ah, the delights of toddler TV!!)

    Ok, perhaps what I'll do instead is just start to look at secure storage .... Thank you for all your help!
     
  17. zaskar

    zaskar Funster

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    At the risk of stating the bl**dy obvious:Blush:, could you not approach the drive from the bottom of the first hill, that way, as you turn in to the driveway, you're already running with the slope?
     
  18. White Rose

    White Rose Read Only Funster

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    I could do with being able to draw a picture, I think ... The road hill is very steep - the sort that bus drivers curse and multi-gear cyclists get off and walk. My dad's lane/drive slope is kind of cambered, so is a gentler angle on its left as you look at it, therefore coming down the hill and turning left into it is relatively easier. The right hand side of his drive is more of a vertical drop than a slope, and I'm not sure there's enough road width to get a van round to get onto the left side. Gosh, that's hard to explain - I have to keep stopping typing to wave my hands around!
     
  19. vwalan

    vwalan Funster

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    you could look at many chassis cabs then get a box to fit may mean shortening the overhang on the chassis. i cut over 3ft off my unit to make it do what i wanted, given what you have said i think you have to think about rearwheel drive . look at iveco daily,s or renault mascotts not masters. (mascotts are rear wheeldrive).you need wheels as far back as you can get them . also right up on the front aswell to help coming out when you turn round. easy sorted with a bit of thought.
     
  20. Theonlysue

    Theonlysue Funster Life Member

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    Rear overhang

    This is fascinating! perhaps a few photos of said area and measurements. Someone might think of a new approach......:clap:

    S
     
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