Swing up tire carrier
CF Veteran
Joined: Oct 2009
Posts: 1,474
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From: south jersey
Year: 1997
Model: Cherokee
Engine: 4.0
Thread Starter
Senior Member
Joined: Jan 2009
Posts: 562
Likes: 1
Year: 1990
Model: Cherokee
Engine: Renix 4.0L
The only part of this that is going to be attached to the hatch is the latch. This tire carrier will act as a whole seperate "hatch" with it's own supports and everything.
I have not taken any real physics classes yet, but I'm pretty good at figuring out how stuff works, and how to make things work. I do have to take some physics classes for my degree which is Engineering Technology: Drafting though.
I will keep this updated, but it may be a while before I start making it. I hope to also include all the vital measurements that make it work in the end so that anybody who wants to do it can.
I have not taken any real physics classes yet, but I'm pretty good at figuring out how stuff works, and how to make things work. I do have to take some physics classes for my degree which is Engineering Technology: Drafting though.
I will keep this updated, but it may be a while before I start making it. I hope to also include all the vital measurements that make it work in the end so that anybody who wants to do it can.
Okay, first off, I LOVE your idea. Second, you're going to destroy your hatch, I believe around 97 (?, please someone correct me) they went back to steel hatches, you may want to go to a pull and pick and find your self a good metal hatch. Third, the hinges will be fine. Four, I agree winches and pulleys are ridiculous. Five, I really don't like the idea of an actuator, it takes away from the whole: pop the hatch, watch it rise; feeling. Six, not sure what background you have in physics, if you haven't had it sign up for it next year (college, highschool, whatever, it will help you out so much). You need to understand moment arms and consider their placement for gas struts. Unfortunately the stock location won't help you much as they are designed to keep the hatch up, in place, more than raise it (SAFETY!) but if your XJ is pre-97 they can be easily upgraded from almost any fullsize mini-van at your local JY. I also bet it wouldn't be hard to add another set above, below, or both around your current struts. Using a couple of assumptions and measurements it wouldn't be hard to figure out the capable weight (assuming you know how much your struts can handle). Seven, I think attaching the whole deal to the hatch is a great idea, I mean when are you going to want to raise the tire but not the hatch? Eight, you're going to need shackles some where should you decide to connect your roof rack to the whole arrangement, different pivot points and all... Nine, PLEASE keep us informed, I would love to recreate this.
Senior Member
Joined: Apr 2009
Posts: 501
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Year: 2001
Model: Cherokee
Engine: 4.0L I-6
I think you're going to find out this won't be possible without an actuator, or god forbid, a winch. I think you'll have to mount your lifting points on the struts lower, unless you use some sort of torsion spring, like you would find in a garage door.
Member
Joined: Jan 2010
Posts: 153
Likes: 0
From: Helena, MT
Year: 1989
Model: Cherokee
Engine: 4.0l
I brought this Idea up to a few friends of mine(hope you don't mind) who are extremely well educated in such matters, and from your basic design we are going to hit a bit of a snag, you reach a point in your leverage called the "grashof condition" I'm not so well educated but basically it means no reasonable amount of force will be able to hold your tire carrier up. There are ways around this, simply moving your shocks around to increase leverage would do the trick but doing that without being in the way of the lift gate would be a trick....
As I'm told, but like I said I'm not so well educated
As I'm told, but like I said I'm not so well educated
Thread Starter
Senior Member
Joined: Jan 2009
Posts: 562
Likes: 1
Year: 1990
Model: Cherokee
Engine: Renix 4.0L
Those pics are just a general idea of what it will look like. And I agree that the shocks won't be able to hold it up by themselves, they are just going to assist with hopefully 80%+ of the weight when raising it. A self "locking" bar will hold the weight when it's up, acting as a safety aswell.
Member
Joined: Jan 2010
Posts: 153
Likes: 0
From: Helena, MT
Year: 1989
Model: Cherokee
Engine: 4.0l
should rob a E-brake off an yota, with its ratcheted rod, and run it so that it locks as you open it in any position you stop in, then you lift and twist it to release.
CF Veteran
Joined: Jan 2010
Posts: 2,059
Likes: 1
From: Indianola IOWA
Year: 1992
Model: Cherokee
Engine: 4.0
Like i said earlier i dont want one but wanting to build one because of this thread.
My plan:
make a plate that goes over the top like the ladder pictured earlier. make like an x across the hatch to similar plates on the bottom. bolt wheel in middle of x and put a 6x6 plate with rubber on it to go against the hatch for a little extra.
some tests
i threw an unmounted 33" mudzilla on my hatch today (with strap running from roof rack) and tried to lift hatch. incredibley hard. i got a bunch of xjs laying around so i buuilt a bracket so i could mount 2 of the hatch shocks on each side and it was still kinda rough to lift. now im kinda wondering what three on each side would do
Does anyone know that weight rating of the stock hatch shocks?
tomorrow
might try 3 shocks on each side but might start to look a little goddy.
also might try playing withe where the shocks are mounted.
And does anyone know of junk yard ones of similar lengththat are super high po?
My plan:
make a plate that goes over the top like the ladder pictured earlier. make like an x across the hatch to similar plates on the bottom. bolt wheel in middle of x and put a 6x6 plate with rubber on it to go against the hatch for a little extra.
some tests
i threw an unmounted 33" mudzilla on my hatch today (with strap running from roof rack) and tried to lift hatch. incredibley hard. i got a bunch of xjs laying around so i buuilt a bracket so i could mount 2 of the hatch shocks on each side and it was still kinda rough to lift. now im kinda wondering what three on each side would do
Does anyone know that weight rating of the stock hatch shocks?
tomorrow
might try 3 shocks on each side but might start to look a little goddy.
also might try playing withe where the shocks are mounted.
And does anyone know of junk yard ones of similar lengththat are super high po?
Thread Starter
Senior Member
Joined: Jan 2009
Posts: 562
Likes: 1
Year: 1990
Model: Cherokee
Engine: Renix 4.0L
Tomorrow I'll get on the computer and draw up the new "revised" idea using a very sophisticated program called MS Paint lol.
I like the novelty of making it as low profile as possible so it appears the tire is just "floating" there. The whole tire will cover up it's own frame mount thing.
I am planning on using 1"x2"x1/8"wall rectangle for the framework stuff to keep weight down.
I like the novelty of making it as low profile as possible so it appears the tire is just "floating" there. The whole tire will cover up it's own frame mount thing.
I am planning on using 1"x2"x1/8"wall rectangle for the framework stuff to keep weight down.
Member
Joined: Jan 2010
Posts: 153
Likes: 0
From: Helena, MT
Year: 1989
Model: Cherokee
Engine: 4.0l
there are several Free design programs out there that are WAY better then paint
Like sketchup
http://sketchup.google.com/
Like sketchup
http://sketchup.google.com/