I wasn't too much of a fan of the hitch mount tire carriers but I had been complaining about having to haul the tire off the roof whenever we headed to the beach. The coolers and stuff didn't fit up there half the time. So after my dad heard me complain and complain get got tired of it. For Christmas he bought me this

http://www.walmart.com/ip/Masterbuil...r-Bar/20512803


The purpose of him buying me that was so that I could build a hitch mount tire carrier. I already had 2" square tubing at the house just collecting rust so this whole build cost me nothing with the exception of buying the light needed to illuminate the license plate.

Materials Used:
2" square tubing
2" x 12" 1/8 thick piece of steel
Wheel stud
Lug nut
Hitch pin

Keep in mind that the tubing had been sitting outside for years so it has surface rust.

I'll grab some completely finish pics tomorrow and show exactly how the tire is secured to the mount.



I was using a cheap 90amp hf welder with flux core wire. The welds look ugly in the pics but after taking a wire wheel to them, they cleaned up very nicely. The hole you see in the lower angled weld was a hole that was already in the tubing and just hadn't been welded closed yet at the time of the picture.

 

ill take it

 

Did you clean off the rust before you welded?

 

He better not have!!!!! Ha ha okay sorry I'm done now

 

I once had the idea of making a set of shoe-springs while I was in metal shop. Think of moon boots. I took a rusty piece of 1x1 and a 1/4" flat sock that I bent and welded them together. Now granted it wasn't spring steel and I didnt know how a proper leaf spring worked at the time. My welds were solid, good bead, excellent penetration. Stood on em ok and hopped a little, both welds shattered between the two pieces. A contaminated weld is a broken weld. I say thisz because I look at your carrier and I see little reinforcement and rusty welds. I would be very sad if that support turned to scrap on the highway. For the sake of safety, cut the tubes off, grind down the metal till its shiny and lay a good bead. Tailgaters will thank you.

 

And to add to that, if your tire falls off because of poor quality, you're liable for any damages to anyone else's vehicle.

 

liability is a *****...

 

The area for welding was grinded down so that there was no rust. What you see there is because I was using flux core wire. The tubing was 2" square 1/8" wall. It is plenty strong and the welds are solid. The moment about the horizontal support is only about 20 ft*lbs. That is hardly any moment to cause the welds to fail. I invite anyone to come take a look at them. I see your concerns with it failing but I assure you that it is plenty strong.

And yes, the whole thing was cleaned of all rust before painting. I just had no need to remove all of it until I was ready for paint.

 

Being an engineer I think I know what you're trying to say, but that really doesn't make much sense. Moment about the horizontal support... moments are around a given point so within the hitch tube or "horizontal support" as you put it, the moment at the base of the vertical column is different than at the hitch face when calculating with vertical planes. I don't know what point you're using to calculate 20 ft-lbs but I'm assuming it's between two vertical planes. That's great if you never drive you're jeep and it's only a static load, but you have to consider the dynamic forces, not just the static. When you accelerate and brake or hit something the mass of the wheel is exerting force in the horizontal plane. When you calculate a moment in the horizontal plane you have a lever arm that I'm going to assume is say 20". With a wheel weighing say 75 lbs and the Jeep accelerating at a constant 1G, now there's a 125 ft-lb moment at the base of the mount. In the vertical direction you have high acceleration loads with pot holes, ruts, roots off-road etc. and you're 20 ft-lbs can multiply very easily, and that's not counting horizontal and vertical forces. Then factor in the fatigue limits of the steel... and well you get the point.

Good to hear you prepped the metal before welding. I would suggest inspecting it periodically once you get it finished to make sure the welds don't fatigue and start to crack.

 

A few tips when using that welder. Slow down the wire feed and do 5-7second welds. making a U motion. When you restart your weld, Draw a question mark and then go back up the weld. Use lincoln brand flux cored wire. And if u ever want to do do thin sheet metal let me know and I'll tell you how to mod it to lower the amperage. I've done a lot with my cheap HF welder. Built my last motorcycle with it and put several thousand miles on those welds. My entire exhaust on my Titan is done that way. and the jeep exhaust.

 

The 20 ft lbs is calculated as a point at the end of the horizontal support with the pinned end being the end welded to the vertical tube. Yes that's for the static load.