Rear Cargo Rack via Hitch vs. Bumper Extension/Deck

[Cerax]

Hi all,

I'm trying to decide how best to mount a mini-split on our short bus (5 window, Chevy 6.0L Bluebird Gasser). Specifically, I'm trying to find out the best way to mount the compressor.

I have seen a lot of people put the compressors on the back on brackets ( like so :

); however, I admit I'm not the biggest fan of this (admittedly for aesthetic reasons).

Instead, I'm drawn to the idea of a back deck/storage area - as this was already something I was interested in. It'd be great to have an extra 2 ft on the back of the bus for the compressor, firewood, etc. (or bikes).

I am trying to figure out the most cost-effective and safest solution to do so.

Option 1: Bumper extension - I see a lot of people on here who have done bumper extensions. I admittedly cannot seem to understand the consensus on how best to do so - where to weld (frame, etc.). I'm also not a welder and the task feels pretty daunting. Here's a good example of the back deck discussion/illustration: https://www.skoolie.net/forums/f27/back-deck-for-window-licker-short-bus-16512.html


Option 2: Hitch attachment + cargo carrier. I admit, it seems to be more accessible/easier to simply get a hitch professionally attached to the back of the bus, and then attach something like this cargo carrier ( https://www.lowes.com/pd/Erickson-Heavy-Duty-Cargo-Carrier-500-lb/1002695764 ). I could modify it to secure the mini split compressor, and still have room for an extra storage box/bike attachments (maybe standing).

We have no desire to use the back deck to stand/lounge on (As cool as it sounds); however, using it for a storage box and compressor seems great.

Does anyone have any experience also debating between these options? Or does anyone specifically use a cargo hitch carrier for a mini split compressor - and what have been your thoughts?

I've tried to do a ton of reading on this - if I've missed an identical thread my apologies!

Thanks!

 

[rustymetalgirl]

I am having some of the same questions about my build, although my bus is a full size 3800 which already extends some 10 feet behind the rear wheel wells. I am reluctant to weld anything to the frame rails, having seen numerous caveats about doing so... I have a salvage hitch from an old suburban that I think could be bolted on with minimal modifications. That would allow attachment of a standard or custom made cargo carrier. I’m not sure if bolting support straps to the bumper would be appropriate or not...

It seems like it could be an advantage to have such a back platform that would be relatively easy to remove if needed or desired?

Does anyone have any thoughts or recommendations on this?

 

[Cerax]

For what it's worth I've reached out to a both few welders and hitch-installation services in my area, ill try to keep the thread updated with what I learn.

 

[Oscar1]

I am having some of the same questions about my build, although my bus is a full size 3800 which already extends some 10 feet behind the rear wheel wells. I am reluctant to weld anything to the frame rails, having seen numerous caveats about doing so... I have a salvage hitch from an old suburban that I think could be bolted on with minimal modifications. That would allow attachment of a standard or custom made cargo carrier. I’m not sure if bolting support straps to the bumper would be appropriate or not...

It seems like it could be an advantage to have such a back platform that would be relatively easy to remove if needed or desired?

Does anyone have any thoughts or recommendations on this?

Yes you are correct you should not be welding on your frame.
And also with a full size bus and the large overhang you already have the tail swing is very wide, you would be making it even more dangerous and awkward to manoeuvre.
My opinion, full size bus build a garage in the back.
Cheers
Stay safe

Oscar

 

[Cerax]

Yes you are correct you should not be welding on your frame.

Is that a blanket rule - or just dependent upon size of bus? (And if not weld onto frame, what** do you weld onto?)

 

[Oscar1]

Is that a blanket rule - or just dependent upon size of bus? (And if not weld onto frame, what** do you weld onto?)

Hello Cerax
It's a very hot topic with many opinions but all my research indicates that
yes that rule applies to all frames, welding weakens them. There are going to be many people saying that they have repaired rusty frames(I've done it) lengthened or shortened frames but take a look under any semi and see if there is any welding on that frame or is it assembled with bolts and rivets? Anything you want to attach like a hitch or bracket for a tool box should be bolted to the frame.
Again just my opinion so do your research
Cheers
Oscar

 

[Cerax]

Hey Oscar thank you so much for the help!

 

[BeNimble]

There was some discussion about putting it in the rear engine compartment, seems a good option. Putting it under the floor...which is going to require reconfiguring the layout so the compressor stays upright.

 

[plfking]

I am having some of the same questions about my build

It seems like it could be an advantage to have such a back platform that would be relatively easy to remove if needed or desired?

Does anyone have any thoughts or recommendations on this?

Mine is easily removable without tools in a couple of minutes, and holds my 240 pounds with no sagging. Specifics start on page 20 of my build thread.

 

[drtbreau]

I'm probably going with a 3' extension welded on. I am planning on putting my mini split "long ways" on the deck and building a cage to bolt down on top the edge of the deck. I will likely bolt my propane tank back there too. My bus is a 24 footer.

 

[Oscar1]

Mine is easily removable without tools in a couple of minutes, and holds my 240 pounds with no sagging. Specifics start on page 20 of my build thread.

That is a very handsome looking deck you have there, nice build
Cheers

Oscar

 

[Rucker]

You might want to rethink locating your propane tank out there. Not allowed, according to the rules for recreational vehicles-needs to be between the front and rear axle if exterior to the bus.

This is for really good safety and liability reasons, I hasten to add before others chime in 'who cares about the rules'.

 

[drtbreau]

Thanks, going back and forth and looking into options; no a whole lotta room in front of my rear tire.

 

[musigenesis]

You might want to rethink locating your propane tank out there. Not allowed, according to the rules for recreational vehicles-needs to be between the front and rear axle if exterior to the bus.

This is for really good safety and liability reasons, I hasten to add before others chime in 'who cares about the rules'.

RVIA also uses an 8X dynamic loading factor for propane tanks, so a mounting for a 100 lb. tank would need to be strong enough to support an 800 lb. static load (applied in any direction, not just down).

 

[rossvtaylor]

If I may...here are my thoughts and personal perspective on welding on or to a vehicle frame. The Federal regs that cover this apply to DOT-inspected commercial motor vehicles, not to our converted buses. So, legally, it appears that welding can be done anywhere on our rigs. From a safety and strength perspective, though, there are potential issues with welding on a frame...especially if it's a heat treated frame. Frame repairs or modifications can be done properly, and even legally on commercial motor vehicles, with input from the vehicle manufacturer. And even without those recommendations, if it's not a commercial vehicle, there are right and wrong ways to do it...practices such as angling the welds, adding reinforcing plates, fish mouths, minimizing the heat affected zone/area of the weld. Sometimes, things just need to be welded and fixed

My personal practice is that I will weld (properly) in non-load-supporting areas of a vehicle. The regs that define a vehicle chassis refer to the load supporting frame of the vehicle and the regulation that addresses the frame of the vehicle prohibits operation of a commercial vehicle with a frame that has damage to the frame rails between the axles. There is a bit of a contradiction in some of the CFR wording...but they do recognize that the frame between the axles is more important than the frame rails or extensions beyond the axles.

So...this overly wordy commentary just means to say...I see no issue with welding on frame or chassis portions of vehicles when it is done forward of the front spring/suspension mounts or behind the rear axle spring mounts. Once you are outside of this load carrying area, I believe it's safe. And unless you plan to operate your skoolie as a commercial motor vehicle, it's legal.

 

[ol trunt]

When I did the wheelbase stretch on my bus I followed the recommendations found in the GM upfitters document. My frame was known to be mild steel which makes it more feasible to weld. Attached is the GM upfitters info:

https://www.gmupfitter.com/files/media/photo/843/2018_Chassis_BstPrac_093017.pdf.

 

[Sharee100]

Go see what Robert Braden has done on his shortie. He has a video on You Tube.

 

[Jaybz]

If I may...here are my thoughts and personal perspective on welding on or to a vehicle frame. The Federal regs that cover this apply to DOT-inspected commercial motor vehicles, not to our converted buses. So, legally, it appears that welding can be done anywhere on our rigs. From a safety and strength perspective, though, there are potential issues with welding on a frame...especially if it's a heat treated frame. Frame repairs or modifications can be done properly, and even legally on commercial motor vehicles, with input from the vehicle manufacturer. And even without those recommendations, if it's not a commercial vehicle, there are right and wrong ways to do it...practices such as angling the welds, adding reinforcing plates, fish mouths, minimizing the heat affected zone/area of the weld. Sometimes, things just need to be welded and fixed

My personal practice is that I will weld (properly) in non-load-supporting areas of a vehicle. The regs that define a vehicle chassis refer to the load supporting frame of the vehicle and the regulation that addresses the frame of the vehicle prohibits operation of a commercial vehicle with a frame that has damage to the frame rails between the axles. There is a bit of a contradiction in some of the CFR wording...but they do recognize that the frame between the axles is more important than the frame rails or extensions beyond the axles.

So...this overly wordy commentary just means to say...I see no issue with welding on frame or chassis portions of vehicles when it is done forward of the front spring/suspension mounts or behind the rear axle spring mounts. Once you are outside of this load carrying area, I believe it's safe. And unless you plan to operate your skoolie as a commercial motor vehicle, it's legal.

Very good info! Never knew about the legality of such things.

Your perspective on safety matches my own- I wouldn’t hesitate to weld to a frame after the last/ before the first suspension mount.

That does bring up a good question though, are frames on the larger busses typically heat treated?

To the OP- I’ve had good success extending the frame for a bumper with nothing more than 5/8x10 bar stock. Or less, the height is dependent on the inside dimension of your frame rail. Bolt/weld two plates to your rails and leave them sticking out as long as you need. Plenty strong.

 

[ol trunt]

Angle iron will give you better lateral strength than flat iron and will be less likely to bend to either side the first time you "jack knife" backing up.
Jack

 

[demoman]

Welding to frame

One thing to remember when welding to the frame is the reason it is bolted or riveted together. The frame needs to bend and flex a bit naturally and the looser connection of the rivets allows this. If it were welded together it would increase the stress concentrations and lead to cracking.if you weld something to the front or back and it ties the frame together it could transfer stress elsewhere and increase the likelihood of cracking.
That being said i have a three axle semi truck that i wanted to tow heavy frailers with and there wasnt room to bolt anything on so i welded a 3/4 inch plate on the back for a hitch. I put so few miles on it and in california the truck will be outlawed in two years anyway so i took the risk. On a bus conversion that you plan to use for more miles and years bolt on is better.