Cherokee spare carrier idea

[Gojeep]

I thought about making a spare go up with the hatch for years. But the problem is that the hatch is not up to supporting it so you would have to make it hinge on a bar that goes across the roof bolted to the gutters on each side. But because now the hinge point is different to the hatch it has to be released from the hatch before both can be raised as the lengths change as it raises between them. But you could make the arms holding the spare telescopic themselves as they raise or have it the same as the Bestop heavy duty TJ carrier where they have an extra set pivots in the arms which allow for the change in length. There was some good pictures of it in Off-Road Adventure issue November 2004 which I have scanner a picture of below and you can sort of work it out in their installation guide as well. http://www.bestop.com/installation_guides/61950.pdf Step 13, 23 & 25 show the links in the open mode where they are shortened. When closed they sit flat and inline with the rest of the arms.
If you had the support bar that goes across the roof sitting up a bit you could mount a bracket to it with a really short gas strut from there to the arms to help lift it. You would still have some assistance from the ones in the hatch and maybe even change those for higher pressure ones to help as well.

I have scanned a page I was talking about.



Now imagine this vertically and you can see what I was thinking about. The small arms move away from the body when opening it to take up the difference in length due to the different hinge points and then lay flat against it when closed.
I think this could be the answer to the problem and it would not be that hard to buy one of these and modify it to fit an XJ but better off making from scratch if not time poor. Just need to work in the gas struts ( like used on some wheel carriers ) to help assist the lift and centre the tyre fixing.

What do you think??

[Snapey]

Hey Marcus - oh you're just full of good ideas aren't you?! I like this a lot - but was wondering if it might be easier to use a spring (mouse trap style, if you know what I mean) instead of a gas strut. This would take up less room and possibly reduce costs. I imagine it would sit around the main bar that ran across the top of the tail gate. This would be a great mount for a high lift jack, but not sure if a jerry can would be good as there would be potential for a change in weight.

What were you thinking so far as fastening to the roof? Would the std Jeep rook rack runners handle both the weight and the shock force over time? Maybe it would need to be incorporated with a basket? Now my imagination is just starting to run away with me!

I'm going to sit down a have a think about this one!

Cheers

Matt

[Gojeep]

Those with a rook rack that attached to the gutters could attach it to that. But otherwise a roof bar from gutter to gutter would be needed with feet about 6" wide. I like you idea using the bar to mount a Hi-lift jack as was thinking what else it could be used for. The spring idea could work too allowing your to have the roof bar lower to the roof line as well.

[Gildo]

One little issue that you will find is if you need to open or close the rack when it is empty. Like when you take off the spare, the amount of lift or preload on the spring is gonna smack you in the chin pretty severley!
Attaching it to the fibreglass rear door will be an issue too, they crack and pull through, will need some serious reinforcement.
Sounds like a great Idea though, be interested to see a development/prototype.

[Chopper in Oz]

I like the idea!

Now go and build one already!!!!

[Gojeep]

Originally Posted by Gildo

One little issue that you will find is if you need to open or close the rack when it is empty. Like when you take off the spare, the amount of lift or preload on the spring is gonna smack you in the chin pretty severley!
Attaching it to the fibreglass rear door will be an issue too, they crack and pull through, will need some serious reinforcement.
Sounds like a great Idea though, be interested to see a development/prototype.

That could hurt with the whole tailgate coming up faster. It was like that with mine already when i took out the rear glass window and fitted a polycarbonate one. But you just pushed the bottom and stood back as it lifted itself up. There would not be many times you would be without the spare on anyway and lifting the tailgate up. Only when repairing punctures I guess.
The fibreglass would not be carrying much weight as the roof bars would mainly. You would have to fit steel plates like the factory swing a way latch attachment has. I think some folded channel formed the follow the contour of the very bottom of the tailgate right along would be best.

[Gildo]

You're definetly an ideas man Marcus, plenty of thought has gone into this so far!
Please consider these as random ramblings and in no way critical of the basic idea, more a brain storming approach to sorting ideas and issues.
The feet of the roof bar will need to be large and secure to support the load and change of COG of the carrier and tyre. IE, The weight is going from "down there" to "out there"
If you had the carriers hinge lowered from the roof bar to be in line with the lift gate hinge, so that the bottom and the top of the carrier and the pivot point are kept parrellel with the gate, you may avoid overengineering the whole thing.
It will definetly need extra lift support for the weight of the tyre so reducing the construction weight will be a priority.
A funky folded alloy sheet fabrication may be stronger than a welded tube fab.