Very simple tire rack holder? With drawing.

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Discussion Overview

The discussion revolves around designing and building a spare tire holder for an off-road Land Cruiser. Participants explore various design considerations, materials, and structural integrity required for the holder, particularly focusing on the metal thickness and support structures necessary for durability during off-road use.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant suggests using 2" square tubing and inquires about the appropriate wall thickness for holding a 100-pound tire and rim, emphasizing the need for durability during hard off-roading.
  • Another participant expresses concerns about a cantilever design lacking lateral supports and recommends a minimum wall thickness of .125" for the steel tubing, suggesting the addition of gussets for reinforcement.
  • Some participants discuss the potential for vibration fatigue affecting the aluminum and recommend using grade 8 bolts for assembly, while others suggest that the pivot point may be a weak spot.
  • There are multiple design modifications proposed, including the use of a pivot mechanism to allow the tire holder to fold down for easier access to the vehicle's rear storage area.
  • Participants debate the thickness of side straps and the grade of pivot bolts, with suggestions ranging from 1/4 inch thick mild steel to grade 10 bolts for durability.
  • One participant proposes a new design to minimize the hitch's protrusion, aiming to avoid damage from off-road obstacles, while others provide feedback on the structural integrity of the proposed designs.
  • There is a suggestion to add gussets to various parts of the design to enhance stability and strength.

Areas of Agreement / Disagreement

Participants express differing opinions on the best design approach, material thickness, and structural supports. No consensus is reached on a single design or material specification, indicating ongoing debate and exploration of ideas.

Contextual Notes

Participants mention various design modifications and structural considerations but do not resolve all technical uncertainties, such as the exact specifications for materials and the best methods for pivoting mechanisms.

Who May Find This Useful

Individuals interested in off-road vehicle modifications, mechanical design, and structural engineering may find this discussion relevant.

lyrikz
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I found this forum by accident and am learning stuff i never thought i wanted to know. I am getting ready to build a spare tire holder for my off road landcruiser.

The metal will be 2" square tubing. The weight it will be holding is a 100 pound rim and tire...

Here is a rough picture. Any recommendations on how thick the metal should be? The hitch i believe is a class 2.

Very rough pic. Now, I am going to be doing hard 4 wheeling with this setup. So i need to make sure its not going to sheer off. Any tips on metal thickness??
 

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lyrikz said:
I found this forum by accident and am learning stuff i never thought i wanted to know. I am getting ready to build a spare tire holder for my off road landcruiser.

The metal will be 2" square tubing. The weight it will be holding is a 100 pound rim and tire...

Here is a rough picture. Any recommendations on how thick the metal should be? The hitch i believe is a class 2.

Very rough pic. Now, I am going to be doing hard 4 wheeling with this setup. So i need to make sure its not going to sheer off. Any tips on metal thickness??

31 views, no response. Am i missing info for you guys to give an educated guess on what i should use? Thanks for taking your time.
 
i do not like a cantilever design with zero lateral supports. too long an arm susseptible to vibration and stress but if you are going to use this design use a minimum of .125" wall thickness steel tubing.i would go thicker if you can afford it..add gussets to the 90 degree angle to reinforce. do not rely on bolts..weld it and gusset..the wheel mount plate should be at least 1/4 steel, 3/8 is better , use three wheel lugs to spread the load..
 
Like Mike said, there's a lot of vibration fatigue that could eventually crack the aluminum, or more likely cause the bolt holes to start looking like ovals, then it cracks. I'd recommend bolting, with Loc Tite, a gusset or two to brace the angle if Mike agrees. I'd use 7-8 inches on a side. Now your weak point might be the pinned hole where it inserts into the hitch.

And, by the way, that trailer hitch hole isn't a perfect square it has a radius at the corners. You will have to knock-down the edges of anything you insert, giving you thin spots.
 
Last edited:
Ranger Mike said:
i do not like a cantilever design with zero lateral supports. too long an arm susseptible to vibration and stress but if you are going to use this design use a minimum of .125" wall thickness steel tubing.i would go thicker if you can afford it..add gussets to the 90 degree angle to reinforce. do not rely on bolts..weld it and gusset..the wheel mount plate should be at least 1/4 steel, 3/8 is better , use three wheel lugs to spread the load..

Ok, here is a new design i will try... Hows this look. I will use 3/16 metal tubing. Its only 20 bucks more.. the design is under the picture... let me know.

Ok looking at the back of the bumper you have these 4 holes. Those 4holes is where you can bolt and aftermarket hitch to it.. I will make a tab that comes off the arm that i can bolt into the bumper while in transit... Then when i need to lower the back, just unbolt and pull the in and it will lay down to open the back... Here is a picture of the back bumper bolt holes. This is what i will bolt the tire holder to.
attachment.php?attachmentid=429489&stc=1&d=1277090183.jpg
 

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excellent..i like the gusset to the tire/wheel mount plate..grade 8 bolts are ok..no need for grade 10 bolts..save some $$
the sumbch should last ferever!

good job!
 
Ranger Mike said:
excellent..i like the gusset to the tire/wheel mount plate..grade 8 bolts are ok..no need for grade 10 bolts..save some $$
the sumbch should last ferever!

good job!

Mike, I am going to have the pivot at where it bolts to the bumper. Any recommendations how to make a pivot to where it would lay down flat? I am stumped there..
 
you want to be able to quickly remove a pin and have the spare tire rack fold down so you may easily load something into the rear storage area..right?
instead of the bottom gusset ( hitch lateral bar to vertical post) drill a 1/2 inch ( or larger) hole through the post and use this as the pivot. ( may require notching the vertical post. next we need to replace the bumper bolts with studs. I would use wing nuts to secure the vertical post. finally i would drill a small hole through this stud and use a hitch pin ( looks like a big hair pin) to keep the wing nit from coming loose...
 
Ranger Mike said:
you want to be able to quickly remove a pin and have the spare tire rack fold down so you may easily load something into the rear storage area..right?
instead of the bottom gusset ( hitch lateral bar to vertical post) drill a 1/2 inch ( or larger) hole through the post and use this as the pivot. ( may require notching the vertical post. next we need to replace the bumper bolts with studs. I would use wing nuts to secure the vertical post. finally i would drill a small hole through this stud and use a hitch pin ( looks like a big hair pin) to keep the wing nit from coming loose...

Ok, added a few more modifications...

What should i make the pivot out of? I added something for the tire to lay back on. Here you go.
 

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  • #10
the side straps should be at least 1/4 inch thick mild steel. the weak point will be 1/2 inch pivot bolt but will take years to wear out...in this case size does matter so over build it and it will last..when you are building this..tack weld the pieces and test fit everything..
make sure everything clears.. once a final design is completed then you weld the assembly
 
  • #11
Ranger Mike said:
the side straps should be at least 1/4 inch thick mild steel. the weak point will be 1/2 inch pivot bolt but will take years to wear out...in this case size does matter so over build it and it will last..when you are building this..tack weld the pieces and test fit everything..
make sure everything clears.. once a final design is completed then you weld the assembly

Side straps= the tabs that the bolts on the bumper go through? What grade should the 1/2 pivot bolt be?

So that appears like it will work pretty good then?
 
  • #12
yes side straps are what the pivot bolt goes thru..grade 8 is good enough..i would try this design
 
  • #13
Ranger Mike said:
yes side straps are what the pivot bolt goes thru..grade 8 is good enough..i would try this design

Ok, final drawing... Look good?

The pivot plate obv. mounts on the pivot arm... missing anything.?
 

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  • #14
add top and bottom and side gussets to plate number 6
 
  • #15
Ranger Mike said:
add top and bottom and side gussets to plate number 6

Mike. After going over the design. It dawned on me, the whole reason I am moving the spare tire from under the truck is clearance. Well now i will have a hitch that hangs out about 8-10 inches or so.. I will be blasting that thing every time i go over some decent size rocks with it hanging out.. SOOO, I am going to try two more designs to run by you that will leave that area free and move the tire carrier up...

Here is my first one. Drawing the second one now.
So, i will have grade 10 bolts holding it in, 1/4 plate mounting to bumper. The carrier needs to fold down... Any ideas on how to do that? I will put the second one up in a few mins.
 

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  • #16
Ranger Mike said:
add top and bottom and side gussets to plate number 6

Ok, here is the second one.. I like this one. The spindle is a big beefy trailer spindle. 2k or 4k pounds. That goes through the bumper which has a plate under it. Then that can just pull out of the way.. When its resting it will be a tight fit and i will have it on a solid rubber bushing with a latch to hold it in place and a pin also...

Thoughts??
 

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  • #17
now that is one class act...smokey yunick would be proud!
 
  • #18
Ranger Mike said:
now that is one class act...smokey yunick would be proud!

LOL, i don't know what that means. ahaha Is that good? Bad?? Talk to me Mike. ahaha.
 
  • #19
Ranger Mike said:
now that is one class act...smokey yunick would be proud!

Ok, i looked up Smokey and he seems to be a pretty cool dude. So would you change anything on the final pivot? Any ideas.
 
  • #20
no ..your design looks solid and i think you got a winner!
let us know how it turns out!
rm
 
  • #21
Ranger Mike said:
no ..your design looks solid and i think you got a winner!
let us know how it turns out!
rm

Ran into an issue. There is no bumper support at the mount location for the pivot. Someone on my landcruiser forum said there was metal back there you can bolt through. Well, when i pulled the panels off there is nothing back there. :(
 

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