A different kind of tire carrier...

[Maxwell]

Hinges wont work off the rack.

 

[ausi02]

I think this could work out, I think it would be sick if you built a frame for the lift gate and use the outside sheet metal as a skin essentially.

Im thinking something like the Detours Tail bone System, very strong but uses stock parts for aesthetics. Maybe just go ahead and put in a cage and use it as a mounting point. You can make this as strong or as weak as you like, its all about optimizing the strength vs time/money

 

[Darky]

I understand that you want to prove everyone wrong, but I think it would be a very good idea to put a backing plate behind the skin of the hatch. It wouldn't even be difficult. Just pull the inner panel, place the backing plate in, drill the mounting holes, mount the rack to the hatch with backing plate, and put the inner panel back on. Nobody'd know, it wouldn't look any different from the outside, but at least that way, you're covered if you over estimated the strength of the sheetmetal. Hanging 300 lb speakers is rather different from hanging a spare from thin sheetmetal.

 

[helliphinon8]

I can see why you would want to mount it on the rear hatch since the stock bumper mounts aren't rated to carry more than 50lbs, but a solid rear bumper with proper bracing would be way stronger and you'd never have to worry about the hatch smashing you in the head. Lol. Good Luck!

 

[GordoSmasho]

I understand that you want to prove everyone wrong, but I think it would be a very good idea to put a backing plate behind the skin of the hatch. It wouldn't even be difficult. Just pull the inner panel, place the backing plate in, drill the mounting holes, mount the rack to the hatch with backing plate, and put the inner panel back on. Nobody'd know, it wouldn't look any different from the outside, but at least that way, you're covered if you over estimated the strength of the sheetmetal. Hanging 300 lb speakers is rather different from hanging a spare from thin sheetmetal.

Who ever said I wasn't doing that? I used my work as a reference because I know how to make thing structurally sound. I will be tying into as much bracing and seams in the door as I can. I'm not dumb. I would not do it if I though it was going to rip out. In my line of work if it isn't done right people die.

 

[mfascuba]

I think his point is well taken though. A tire might weigh 60 lbs, and the mounting bracket and tie-in points may well be adequate for a 60 lb load plus a generous safety factor sitting in the driveway. When you factor in dynamic loads the stresses become much higher. On a moving vehicle the acceleration and braking forces could triple the loads, the vertical movement and jarring for being on the trail could be much higher. It could come down to what kind of bumpers you have between the rear frame and axle - a softer bumper will lessen the impact loading that the tire will have on the mounting points, where a harder bumper will abruptly halt the movement of the vehicle - the tire will still try to keep going (inertia).

I'm curious to see the final product - it may be more challenging than your assessment has planned for.

Mark

 

[Darky]

Who ever said I wasn't doing that? I used my work as a reference because I know how to make thing structurally sound. I will be tying into as much bracing and seams in the door as I can. I'm not dumb. I would not do it if I though it was going to rip out. In my line of work if it isn't done right people die.

I could've swore I saw someone else mention using a reinforcement plate inside the hatch and your reply was:

I wa actually thinking of spreading the load out a bit. Four to six attatchment points. One at each corner of the door at least. Deffinately not like a stock wrangle tire mount. Im going to get on it. It will most likely be made out of 1.5 box stock and I will be mounting a 35" on a Toyota 15 x 7 inch rim

I couldn't find the person I thought I had seen, but I stand by my statement. The above quote sounds like you are planning on just tying into the hatch itself. If I'm wrong, I apologize, I misunderstood your plans.

I hang 300 pound speakers over peoples heads for a living. I know how to make it secure. There will be no problems with it ripping sheet metal.

I think I'm just going to have to do it just to prove it to the skeptics. I think it will work. The only uncertainty i have is with the struts and strut mounting points.

The only reason I mentioned this statement is because tying into studs in the wall/ceiling to hang stationary speakers is indeed different from tying into a thin piece of sheetmetal with a tire and rack that will be bouncing around. A lot more and different forces involved.

What I am building will as i said in my original post be mounted to the lift gate only. It will also as i said before mount at the top bottom and middle of the gate with reinforced mounts sort of how a rack covers the roof but only ties in at the outside points like the gutter rails. all of the material for the rack should only weight about 20 - 25 lbs. So that plus the tire and wheel will total about 100 lbs.

How will you be reinforcing the mounts?

I think his point is well taken though. A tire might weigh 60 lbs, and the mounting bracket and tie-in points may well be adequate for a 60 lb load plus a generous safety factor sitting in the driveway. When you factor in dynamic loads the stresses become much higher. On a moving vehicle the acceleration and braking forces could triple the loads, the vertical movement and jarring for being on the trail could be much higher. It could come down to what kind of bumpers you have between the rear frame and axle - a softer bumper will lessen the impact loading that the tire will have on the mounting points, where a harder bumper will abruptly halt the movement of the vehicle - the tire will still try to keep going (inertia).

I'm curious to see the final product - it may be more challenging than your assessment has planned for.

Mark

I also am interested to see what you come up with, but want to make sure you think this through fully and don't end up with something that could rip through your hatch and go bouncing into traffic or even just fall off on the trail.

When you come onto a forum and ask for advice, don't get pissy about said advice.

 

[bigalpha]

In ritter's idea - you have to make sure to account for the fact that the arm holding the tire is going to move relative to the hatch.

 

[casm]

I also am interested to see what you come up with, but want to make sure you think this through fully and don't end up with something that could rip through your hatch and go bouncing into traffic or even just fall off on the trail.

This is key. It has to be done right. And, as someone who has spent a fair amount of time looking into doing the same type of tailgate carrier proposed here, allow me to offer a few observations I've come up with in eyeballing things and sketching out ideas on cocktail napkins.

The local junkyard has a YJ sitting there with the stock carrier still bolted to the tailgate. My opinion is that this would be the best mounting hardware to start with as it's already properly-spaced to give you the distance needed between the tailgate and tyre, and has the standard 5 on 4.5" bolt pattern. If you need more tyre-to-tailgate clearance for something really wide, install longer wheel studs on the bracket and place threaded shims over them as necessary to get the spacing needed.

The need for reinforcing the tailgate at the mounting points is a known quantity; we're all in agreement there. While I get where you're going with the idea of forming the bracketry in such a way as to spread the load across the sheetmetal, depending on how much of a spider effect this gives just reinforcing each mounting point may not be sufficient. Basically, you may have to run a backing plate across the entire rear face of the tailgate. At the very least, they may have to run vertically between in-line mounting points. Expanding on that: only reinforcing the rear face may not be sufficient; you may also have to plate the front face, basically creating a sandwich effect.

Lift struts. Again, it's a known quantity that the stock ones won't be up to the job. However, a secondary concern that came up was the angle they'll be at when open - essentially, that their mounting points on the tailgate would need to be moved further down in order to get the centre of mass of the tyre more within the midpoint between them and the tailgate hinges. Given the shape of the hatch and body around the taillights, this may not be practical.

Tailgate hinges. While the '97-up hinges are arguably much improved over the earlier ones, they weren't designed to have an extra hundred or so pounds of weight on them - and it's not unknown for cracks to develop around them. Not common, certainly, but when it has been known to happen it has happened with everything operating to spec. It's also not clear how they would be beefed-up and still retain stock operation.

On a purely practical level, you're going to have two subsidiary physical constraints to contend with: the rear window and the rear wiper motor.

As regards the rear window, this is going to dictate the mounting height of your carrier since you can't bolt into or weld glass - and if you look at most commercially-available carriers (including the factory ones) on '97-up models, the top wheel stud is usually at or above the bottom edge of the rear windscreen. The lower you have to mount it, the further down the bottom edge of the tyre is - and the greater the chance of smacking it off of a rock or other obstacle when you come down off of it. Obviously, this is going to result in a lot of damage.

Semi-related to that: remember that the wiper motor lives in the tailgate too. Granted, that could easily be removed because a rear wiper is a nice-to-have rather than a necessity, but if you're going for stock operation it may be a consideration. Personally, I find it useful on the trail because I like to be able to see where I'm going if I have to back up and the rear window's filthy, but it's a matter of preference so YMMV on that one.

With respect to the two points raised above, I do realise that depending on the design of your carrier it may be possible to offset things in such a way as they can be either dialled out or at least made lesser concerns. However, my opinion is that they are still up for consideration as part of the design process.

And, one final thing that falls into the liveablity category: the extra height you'll have on that tailgate once all is said and done when it's opened. Fully-open, the tailgate (eyeball measurements, so take accuracy accordingly) sits about 4" above the roofline. Add a nominal 14"-16" of tyre to that, and you're at roughly the same point a roof-mounted carrier will be. If you ever have to deal with parking garages on a regular basis (and I've been there with both a Surco rack and a Mopar tyre carrier), you may not have decent access to the cargo area from the hatch even if you're OK on ceiling clearance when it's open. Granted, that's something you just accept and live with, but again is something that should be factored in.

With all of that said, I believe there may be one other way to accomplish this and eliminate some of the inherent drawbacks, albeit doing so from a very different angle: convert the tailgate to a side-swing type rather than a flip-up. However, for the amount of work involved, it may not necessarily be a better approach, just different: you'd still have the same amount of work involved to mount and reinforce the carrier, but would additionally have to re-engineer hatch operation to suit.

And finally, please don't take any of this to mean that I (or anyone else) am trying to discourage you from doing this. Personally, I really like seeing unique approaches to things, and would love to see this be done successfully - it really is a case where I'd love to be proven wrong, but I want to be proven 110% wrong

 

[GrimmJeeper]

Just stopped in to add that lift struts are easily attainable from napa, I believe they come rated from 20 to upwards of 350lbs and in lengths from 8" to over 60". We have an entire catalog of them at my shop.

 

[Ritter4.0]

In ritter's idea - you have to make sure to account for the fact that the arm holding the tire is going to move relative to the hatch.

Both the hatch and tire carrier arm will move seperatly from each other. The only thing the tire carrier arm has to do is go higher than the hatch, which being lifted, does not have to open all the way anyway.