Another brilliant DIY mod...

[Rescue Ninja]

They said the same thing to Henry Ford.

Thanks Bushman. (Of course it can be argued there have indeed been lots of Ford related accidents...) Just trying to keep it all light hearted...

I appreciate the safety related concerns. I am a nurse, not an engineer. That said, I'm a pretty smart guy with a lot of real world experience and more than a few lessons in physics. Here is my rational in going forward with this project.

1.) The manufacturer rated the product for 140 pounds. Yes, I am throwing a tire and gas cans on instead of bikes, but the weight of all these items when filled and mounted stays within the manufacturer's requirement. (I don't see the need to carry 70lbs of gas around town on a daily basis, so the Jerry cans will only go on if I plan to be out in the woods for a few days.)

2.) The manufacturer never intended it to carry tires and stuff, but the rack was designed to withstand the forces of up to four bikes swinging around out at the end of its horizontal bars. Even if the swinging is a non-issue because the bikes were properly strapped, the center of balance remains high and torque/rotational forces are multiplied by the length of the rack. By having the center of gravity lower and less spread out, the rack is theoretically under much less stress.

As things stand, trying to shake the spare around just shakes my 4500 pound rig. The mods to the rack itself are minimal enough (the addition of one bolt and three screws) that the risk of use should be equivalent to using the rack as intended. Hopefully, I'm right. I am willing to accept that I may not be, which is why I plan to be very suspicious of it for quite some time. I believe that only time and trail testing will provide anything more than speculation. While we are awaiting the results of the trail testing if anyone feels I have overlooked something or has other constructive feedback, please feel free to help out. I welcome meaningful input and feel forums like this help all of us when energy is spent collaborating.

 

[DetroitDarin]

Like you mentioned - WHERE the weight is matters too - your set up is probably fine, because the weight seems inboard vs sticking out on racks. But - probably is a terrible word. Keep testing - and let us know how it works out, please?

Darin
Puyallup, WA 2005-2008

 

[155mm]

I think it'll be fine; As long as you're not jumping the vehicle or anything crazy like that.

 

[Thirty-Nine]

Regardless of its perfection or imperfection, it's a great idea. I'm sure someone could have something custom-fabbed to make this work, too. Personally, something like this would be idea for my tiny Suzuki in terms of a place to carry some water or gas.

Great idea.

 

[Boost Creep]

the biggest thing i think is that it would be a pita to lift ~120lbs every time i want to get in the back

 

[Wise Old Jason]

the biggest thing i think is that it would be a pita to lift ~120lbs every time i want to get in the back

Lift with your back, LIKE A MAN!!!!


YYEEAAUUUGGGGHHHHHHHHHHHHHHHHHHHHHHHHH!!!!!!!!

GET TO THA CHOPPA!!!!

 

[Rescue Ninja]

...~120lbs every time i want to get in the back.

I'm hoping it won't be that bad, but we'll see. I've been running around town with just the spare all week, and I can get the rack up with one hand. Once it's up, the rack is balanced enough that I don't have to hold it at all while securing it.

My one week status update is positive. I did add something like this to eliminate any play there was at the hitch itself.

 

[Rescue Ninja]

Out of respect for those who have helped keep me grounded because they are pretty sure this is little more than a hot mess, I think for now I'm calling my setup a Hitch MESS (Hitch Mounted Extra Spare System). Thanks for all the input everyone.

 

[Wise Old Jason]

It's awesome. Keep this thread updated.

 

[RMP&O]

I thought about doing a hinged overhead rack some time ago on a truck I was building. It would allow for the rack to serve as an awning. It also would allow for the truck to be a pop-top camper and still be able to carry plenty of stuff up top.

I never did it though, just thought about it.

Cheers

 

[Thirty-Nine]

I got curious, and I see there are companies who make a hitch-mounted spare tire carrier. Might be a bit beefier than the Thule rack for anyone thinking of trying this out. I'm sure it could be modified to hold gas cans and such.

The Curt 31006 is a low, angled version. Wouldn't work for jerrycans, though. Also might impede your approach angles.
http://www.curtmfg.com/part/31006


I also saw this, which looks pretty neat. Ain't cheap, though!

http://www.tiregate.com/hg-series/

 

[Rescue Ninja]

I saw the tire gate while I was brainstorming my project. I love it. If money were no option, that would be mounted instead of a modified Thule. As it is, my track cost a total of $10 after the hardware for the bracket I made the other day.

 

[Mo4130]

Check out tiregate.com Expensive but when you consider its removable and you can keep the stock bumper.......for what its worth

 

[Wise Old Jason]

Yikes, dude. They are proud of their ****.

It is cool, but I can think of a million better ways to drop $1000.

 

[Toyotero]

Ninja,

I dig the idea; I've thought of doing something similar myself, except that I dislike carrying around gas cans for anything other than a few pints for a stove.


I think the major weak point in re-purposing a bike rack for a project like this is likely the hinge and lock mechanism...

What grade are the fasteners? The grade relates to the hardness and the stress (force/area) it would take to shear it, CBI's rack appears to be 7 or 8, yours is likely 5, so you'll definitely want to inspect that and I'd look at increasing the size of the hinge pin and probably the lock pin.
Larger & harder = stronger.

One thing to remember is that while the vehicle is in motion and hitting bumps (such as pot holes) the force on the rack by the mass of the objects will be much greater that when stationary, and the rack should be built to handle the maximum calculated plus a factor of 3X or 4X.

Compare the hardware of CBI's rack designed to take this load. One thing to remember is that CBI's was designed to be used offroad in a bumpy terrain in which the load would be dynamic (accelerated, IE, moved around a lot) often, where as the bike rack is mostly designed for on-road use which is mostly static (very little acceleration, bumps, etc)



The new rack where the bottles sit, what it is made of? Would you trust it to hold your weight if you were to stand on it? How about hopping on it several times (which would simulate the forces involved on a bumpy track) You might consider reinforcing them with a pair of pieces that would be in tension when needed. Personally, I wouldn't trust anything less than 0.125X.5X.5 angle welded up and reinforced for such duty if I were to build it.



Cheers.