Spare Tire Mount - another way

[kdlamoreaux]

After reading several awesome posts about mounting a spare tire under the coach I set out to attempt it. While I was blocking the tire up so I could measure for some sort of cross bracket to go between the frame rails I noticed the back of the receiver hitch is open and just the right height. I had some spare 2" square stock left over from another project that was just the right length~20" long. With the tire under the coach (wheel offset down) I inserted the tube into the receiver ~3", the other end was now completely supporting the wheel. I drilled a 3/8" hole through the square tube and bolted the wheel to the square tube with a locking nut. For the other end i drilled a hole through the receiver and the square tube and bolted them together. I think it came out awesome, the tire is very secure and it was super simple.

[croused]

Originally Posted by kdlamoreaux

After reading several awesome posts about mounting a spare tire under the coach I set out to attempt it. While I was blocking the tire up so I could measure for some sort of cross bracket to go between the frame rails I noticed the back of the receiver hitch is open and just the right height. I had some spare 2" square stock left over from another project that was just the right length~20" long. With the tire under the coach (wheel offset down) I inserted the tube into the receiver ~3", the other end was now completely supporting the wheel. I drilled a 3/8" hole through the square tube and bolted the wheel to the square tube with a locking nut. For the other end i drilled a hole through the receiver and the square tube and bolted them together. I think it came out awesome, the tire is very secure and it was super simple.

So if I understand correctly, its cantelevered from the back side of the trailer hitch with your square stock but the other end of square stock is free - is this rigid enough to endure?

[kdlamoreaux]

Originally Posted by croused

So if I understand correctly, its cantelevered from the back side of the trailer hitch with your square stock but the other end of square stock is free - is this rigid enough to endure?

I think it is more then rugged enough. The tire weighs ~80lbs and the center of gravity is located ~13-14" from the edge of the receiver. Curt sells a 24x60 Cargo Carrier for 2" Hitches that is rated for 500lbs and the Overall distance from center of hitch pin hole to outside edge of carrier is 44-1/4" and it uses the same (actually thinner walled) square tube. I think it will hold up just fine.

[croused]

Originally Posted by kdlamoreaux

I think it is more then rugged enough. The tire weighs ~80lbs and the center of gravity is located ~13-14" from the edge of the receiver. Curt sells a 24x60 Cargo Carrier for 2" Hitches that is rated for 500lbs and the Overall distance from center of hitch pin hole to outside edge of carrier is 44-1/4" and it uses the same (actually thinner walled) square tube. I think it will hold up just fine.

Good answer thanks!

[kdlamoreaux]

I finally had a chance to take a few pictures of my spare tire mount. One is a side view with the trailer hitch to the left and the other is a view looking up at the underside of the coach.

[croused]

Originally Posted by kdlamoreaux

I finally had a chance to take a few pictures of my spare tire mount. One is a side view with the trailer hitch to the left and the other is a view looking up at the underside of the coach.

Smart!

[Chance]

Originally Posted by kdlamoreaux

I think it is more then rugged enough. The tire weighs ~80lbs and the center of gravity is located ~13-14" from the edge of the receiver. Curt sells a 24x60 Cargo Carrier for 2" Hitches that is rated for 500lbs and the Overall distance from center of hitch pin hole to outside edge of carrier is 44-1/4" and it uses the same (actually thinner walled) square tube. I think it will hold up just fine.

Nice use of receiver.

Yeah, your tube should be plenty strong. If anything, I'd worry about the 3/8" bolt holding the wheel down on tube.


By the way, are you still able to use receiver hitch or does tube go too far in to insert a hitch from other end?

[kdlamoreaux]

Yes, the receiver still works fine. I did the entire install with the ball hitch in place. So far I've driven about 400 miles both towing a trailer and just the RV and haven't noticed any movement at all. I did consider a larger bolt but the tensile strength of a grade 2 3/8" 16 bolt is ~5700 lb so I thought there was plenty of margin.

[Chance]

Originally Posted by kdlamoreaux

Yes, the receiver still works fine. I did the entire install with the ball hitch in place. So far I've driven about 400 miles both towing a trailer and just the RV and haven't noticed any movement at all. I did consider a larger bolt but the tensile strength of a grade 2 3/8" 16 bolt is ~5700 lb so I thought there was plenty of margin.

It's great that you were able to keep full use of your hitch receiver. I'm also curious how you found it easier to mount assembly. Do you first bolt tube to wheel and then lift tube into receiver? Some other way? Inquiring minds want to know.


My comment about the bolt was more about it providing adequate stability to keep tire/wheel from rocking side-to-side. If you notice on most tire carriers they often use two or more bolts spaced out with wheel resting against a large flat surface that makes it easy to limit motion. In your case the wheel is bolted to a surface less than 2-inches wide, so bolt doesn't have as much leverage to restrict rocking without much higher stresses. Unfortunately in a case like this it's nearly impossible to estimate dynamic loads so they lead to some concern.

[kdlamoreaux]

Originally Posted by Chance

It's great that you were able to keep full use of your hitch receiver. I'm also curious how you found it easier to mount assembly. Do you first bolt tube to wheel and then lift tube into receiver? Some other way? Inquiring minds want to know.


My comment about the bolt was more about it providing adequate stability to keep tire/wheel from rocking side-to-side. If you notice on most tire carriers they often use two or more bolts spaced out with wheel resting against a large flat surface that makes it easy to limit motion. In your case the wheel is bolted to a surface less than 2-inches wide, so bolt doesn't have as much leverage to restrict rocking without much higher stresses. Unfortunately in a case like this it's nearly impossible to estimate dynamic loads so they lead to some concern.

I installed the square tube by resting the rear edge of the tire on the receiver hitch and lifting the front of the tire as I inserted the square tube. then I let the tire rest on the tube as I aligned the bolt hole.

The tire rests pretty close to the bottom of the coach ~1/2"-3/4" so the maximum excursion from horizontal is only a couple of degrees. Even given the max acceleration due to the over hang of the coach from the rear axle is still well within the bolts capability.

[2016vegas]

I did a bit of hybrid using the 2x6 and 2 inch tube. After 15 miles, no shifting. Awesome.

[kdlamoreaux]

After ~5000 miles of New England (rough) driving I am happy to say that my tire mount hasn't moved and is totally secure.

[2016vegas]

Originally Posted by kdlamoreaux

After ~5000 miles of New England (rough) driving I am happy to say that my tire mount hasn't moved and is totally secure.

Same. 3000mi. I did pretty much same thing but added a bolt through the tube and distal lug hole for insurance. Thanks for the great idea.

[tigwelder]

ever wonder why a receiver has metal welded around it on front side? and not the back

[Chance]

Wonder? No.

Seems obvious, unless it's a trick question.

[Druff]

So the tube doesn't peal open at the weld.

[gnach]

The square tube is welded together down it's length. The ring reinforces the tube against the repeated tongue weight loading from stressing the weld and stretching the opening. +/- 2cents

[Mo_Mike]

Originally Posted by kdlamoreaux

After ~5000 miles of New England (rough) driving I am happy to say that my tire mount hasn't moved and is totally secure.

Can I ask where you got the tubing at?

[2016vegas]

This was my source for the metal tube 2' long x 2" square https://www.metals4uonline.com/

[tigwelder]

you can do what you want . any slight front end mishap you can be sure that tire will go through your gas tank first. if that little bolt breaks i pity the person behind you.