Rear RV Spare Carrier

 How can I carry a spare on the rear of my Jayco 26Y RV?

There is a mryiad of opinions on whether carrying a spare on a class C makes sense. Jayco suggests it is unnecessary because:

• It is dangerous to try and change a spare of this size on a vehicle this big
• You need special tools to change a spare like this one
• It's best to get a roadside service.

Therefore my RV did not come with a spare and it made me uneasy!

Jayco is right ... but!

Stories from RVers that had a flat suggest that there are other important things to consider. Such as:

• You may not have cell service and cannot call roadside service
• Roadside service may take hours to get to your location
• Roadside service may not have your size tire in stock and have to order one

You need a flat tire plan

I decided that we needed a multitier flat tire plan so this is what I came up with.

Tier 1:We are within reach of Roadside Service but they do not have our tire

• Subscribe to a roadside service
• Carry a spare tire and rim

Tier 2: We cannot get roadside service

• Carry a spare tire and rim
• Carry a tire changing tool kit

Spare Tire Kit

Details of my kit are here: https://donstronicthings.blogspot.com/2022/06/spare-tire-kit-for-jayco-26y.html

A common denominator present in all tiers of my flat tire plan is the need to carry a working spare.

To this end, I got a spare and put it up in the loft above the cab.

Lofty Approach

I put the spare in a plastic bag and laid it on top of a piece of cardboard. This kept the loft area free of tire debris and made it easy to push and pull the tire in the loft.

This tire and rim are heavy! Although at 72 I am able to slide the tire out of the loft and onto the RV floor it took all I had. I could easily see that moving this tire would eventually be impractical for me.

We stored and moved the spare in this manner for about a year but with the notion that it was a temporary storage solution.

Since the center section of the loft had to remain in the down position my wife found it more difficult to get in-out of the passenger seat. As we all know the passenger chair is too close to the doghouse to comfortably lower onesself into the passenger seat.

So with the usual wife's encouragement, I started to think about an alternate storage location for the spare.

Where to store the spare on my Greyhawk 26Y

There seemed to be 3 viable approaches

1. Store in a rack in front of the radiator
1. I did not like blocking the radiator
2. Store underneath up in the chassis
1. My shorter RV did not have enough space :( I would have preferred this method.
3. Hang it on the bumper
1. My only choice. I knew that the bumper was not stout enough to cantilever the weight of this spare.
2. Other approaches simply put the spare carrier in the rear reciever while providing another reciever outboard to connect something being towed. I could not imagine hanging (cantilevered) a truck tire and rim in this manner. The rotational forces on the hitch mounted adapter would be large and the possibility of breakage would be high.

The Rear Spare Carrier Rack Design

Reinforce the rear bumper

I researched how others reinforced their bumper (some did not... yikes) and found brackets on Amazon like this:

Heavy Duty Bumper Brackets

I decided that the compatibility of these brackets with my RV was going to be hit or miss and that I would likely have to modify the purchased brackets.

I, therefore, decided to make my own. They are fabricated from 1/4 steel plates purchased from the local Metal Mart. They were designed to capture the bumper while mounted to the frame. There were convenient locations to do so.

I decided to put one of these brackets on each side of the bumper mounted to the frame.

Carrier Design & Fabrication

Features:

I decided that the carrier needed these features.

• Mounted to the rear bumper to the right side of the hitch and left of the ladder
• Removeable and allow other things (bike rack) to be mounted on that location
• One person can remove the spare
• Reduce the cantilever reducing the twist force on the bumper
• Does not obscure the rear lighting
• In view of the rear camera
• Safe operation under way. Having a spare fly off at 70mph would be a bad day.

Design Choices:

• Use a store-bought receiver that mounts to the 4" bumper:  https://amzn.to/3e1DBls. 
• Design and build a rack that would swing down from a pivot point to the ground reducing the load on the operator.
• Mount the spare to the carrier using the same studs and lug nuts as the hubs. In a pinch, these could be used if during a tire replacement they get lost.
• The rack is removable from the receiver. Although I could have attached the rack directly to the bumper I wanted to be able to remove the spare carrier and use the reciever for something else like a bike rack.
• By mounting the tire vertically resting on  top of the bumper the weight of the spare is perpendicular to the bumper. This dramatically reduces cantilevered forces. 

Bumper Mount Reciever Adapter

Design Prototype

Due to the complexity of the carrier, I decided to make a CAD model and then build a prototype from wood. I expected that there would be problems with getting all of the parts acurately located so that the tire was upright and resting on the bumper when stored while being able to easily swing down for removal.

Fusion 360 CAD model

The design consists of:

Bumper Adapter Assembly: a purchased assy that bolts a reviever to the bumper

Post: this upright 2x2 tube holds the tire for mounting and dismounting.

• Two studs welded through this post to hold the tire.
• A lower pivot point hole and bolt 
• 2x side plates (welded) with three holes
• Two bolts to secure the post in the up position

Reciever Coupler: this 2x2 tube is inserted into the bumper reciever

• A hole to accomodate the posts pivot
• A hole for securing the post in the up position
• Internal locking nut to secure the coupler to the reciever

Tire Rest Bracket: a 4 four piece welded assembly made from 1/4" plate. This assembly guides the post to the upright postion and provides a flat surface for the tire to rest. 

• One welded face plate with two holes for mounting to the front of the adapter
• Two welded 1/4" side plates to align and secure the post in the upright postion.
• One tire rest plate on which the tire rests when in the up position.
• Two holes in the side plates to secure the post in the upright position.

Operation:

To remove the spare:

• Remove the bolt in the Tire Rest Brackets side plates
• Remove the bolt that interposes the Reciver Coupler. This is the rear bolt in the posts sideplates.
• Do not remove the pivot bolt
• Gripping the top of the post rotate the post with tire attached to the ground.
• Remove the tire retaining lug nuts with a tire wrench
• Remove the spare tire for mounting on the RV

After replacing the flat tire with the spare:

• Place the flat tire on the posts studs and fasten with the lug nuts.
• Rotate the post and tire to the up position.
• Replace the bolts that were previously removed to dismount the spare
• Replace the forward bolt in the Tire Rest Bracket
• Replace the bolt that interposes the Reciver Coupler

Prototype

The proto was made from wood. The individual parts were milled to the exact size and thickness that the metal version would be. 

Final Assy

Ready for mounting

Tire mounting

Tire fastening

Welded stops hold the bolt so that only one wrench is needed

Hitch Extender added to accomodate close fitting mounts. Not needed for my toad

Side plates

Reciever Coupler

Cooupler to reciever interfaces typically have some play. In towing applicaitons this amount of movement is normal and does not create a problem. In this application however any play in the instert to reciever interface allows the carriers post to wobble. To reduce any rotation of the carrier post the adapter cooupler needed to be solidly mounted to the reciever.

I decided that the best way to solve this was to weld a locking nut on the inside of the coupler tube. Easier said than done! How do you get a nut welded 10" down in a tube.

Done!

When mounted the tire rests on the bumper fastened to the carriers post. The tire is close to (1/4") but not touching the wall of the RV. 

Fabrication Notes:

I decided to reduce costs and itteration frustrations I would fabricate the carrier myself using the wood prototype as a model.

I started cutting the steel parts using a hand jigsaw with a metal blade. Than I found a band blade that would run on my HF bandsaw and this dramatically reduced my cutting time while yeldin better results.

This blade cut the 1/4" steel like butter leaving a clean surface ready for welding.

Bandsaw blade

I assembled the carrier drilling the fastner holes guided by the CAD models drawings. I tack welded the parts to check the overall fit and operation of the assy.

After cleaning up the joints I took the tack welded assembly to a local welder. My welder is not hot enough and my welding is not pretty and likely not as strong as I would like.

As you might expect there were multiple itterations of the wood model that translated well to the steel version. I did have to increase the tolerance on the mounting holes of the steel version to facilitate easier insertion of the mounting hardware. 

Testing:

We took the RV with the mounted spare across town to get gass. We then travelled to our favorite fishing spot 45 min away at speeds up to 70mph. The carrier mounting was SOLID!

Watching the spare in the rear camera

Cost

Materials:

• Reciever adaptor: $41
• *Metal: $50
• Hardware: $15
• Welding: $30
• Paint: $10

Total Materials: 146

*Purchased from local "Metal Mart" from offcuts

Tool Investment:

• Band saw blade: $23