DIY motorcycle rack | GTAMotorcycle.com

DIY motorcycle rack

Hmmm I was expecting to see duct tape . . . lol
 
I would be concerned with the 1 x 1 aluminium, especially hand-bent. Motorcycles have a lot of vibrations, and bending that thin section of aluminium without annealing (to re-crystalizing the grain structure) isn't a good idea as well.

Whenever you see the mounting hardware for a top box, you see that the mounting racks usually tubular - and usually steel. SWMotech makes a small aluminium rack that fits top cases with adapters, but I've actually heard cases of it fatiguing and cracking with more than 10 lbs attached to it.

If you're interested in this concept and want to do it fairly cheaper, I'd find a welder and bend/weld/fasten some tubes to do the job. Or, get a trunk mount kit for your bike but just top it with a sheet metal plate.

That said, I like the concept and support the can-do effort. Just check it for cracks every so often!
 
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Anyways, to break it down...

Good: should not crack ever...

Topcasebracketleftside640x360.jpg


So-so: Users have found cracks after carrying rated loads repeatedly:
gpt.05.299.150__03780_std.jpg


Frightens me!
IMG_0733-300x225.jpg
 
I would be concerned with the 1 x 1 aluminium, especially hand-bent. Motorcycles have a lot of vibrations, and bending that thin section of aluminium without annealing (to re-crystalizing the grain structure) isn't a good idea as well.

Whenever you see the mounting hardware for a top box, you see that the mounting racks usually tubular - and usually steel. SWMotech makes a small aluminium rack that fits top cases with adapters, but I've actually heard cases of it fatiguing and cracking with more than 10 lbs attached to it.

If you're interested in this concept and want to do it fairly cheaper, I'd find a welder and bend/weld/fasten some tubes to do the job. Or, get a trunk mount kit for your bike but just top it with a sheet metal plate.

That said, I like the concept and support the can-do effort. Just check it for cracks every so often!

Yup, definitely going to fail before long. That's 6061 aluminium he's bending, he's not reinforcing the corners, and he never radiused the edges of his cuts. In these pics you can kinda almost see the aluminium stress lines where it changes colour right where the bend is.
http://littlesvr.ca/grumble/wp-content/uploads/2012/09/IMG_0719.jpg
http://littlesvr.ca/grumble/wp-content/uploads/2012/09/IMG_0733.jpg

I support the do-it-yourself attitude also, but this one in particular is not a good solution.
 
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Heh, I know, I didn't have much hope when I finished it, but it turned out surprisingly sturdy and lasted for a long bumpy wet trip! :)
 
Hey, glad you made it home safe! I wouldn't promote the concept 'tho.

And it was nice to go back and think about my degree... I stopped short of dusting off my solid mechanics texts because that would probably irritate my wife on a Saturday night.

I'm actually thinking about similar stuff myself - Givi discontinued the Wingrack fitting kit for my bike, so I'm debating having a welder replicate Givi's mount brackets for it - and then powdercoating it a fun color. Will post if I do it.
 
Speaking of welding - is that something you can learn on your own, or do you need to go to school for that? Are the basic tools you need expensive? I wouldn't mind learning it, for next time I have to make something out of metal.
 
Speaking of welding - is that something you can learn on your own, or do you need to go to school for that? Are the basic tools you need expensive? I wouldn't mind learning it, for next time I have to make something out of metal.

Decent Mig welder is 600+. Also leave Aluminum welding to the pros.
 
I would be concerned with the 1 x 1 aluminium, especially hand-bent. Motorcycles have a lot of vibrations, and bending that thin section of aluminium without annealing (to re-crystalizing the grain structure) isn't a good idea as well.

Whenever you see the mounting hardware for a top box, you see that the mounting racks usually tubular - and usually steel. SWMotech makes a small aluminium rack that fits top cases with adapters, but I've actually heard cases of it fatiguing and cracking with more than 10 lbs attached to it.

If you're interested in this concept and want to do it fairly cheaper, I'd find a welder and bend/weld/fasten some tubes to do the job. Or, get a trunk mount kit for your bike but just top it with a sheet metal plate.

That said, I like the concept and support the can-do effort. Just check it for cracks every so often!

What if you apply some heat to the corners, would that re-crystallize the structure?

I'm thinking he could have weld the corners by bringing it to an Al welder. He could also try riveting the corners
 
Yep, welders are not cheap. Sometimes you can find them used for a bit cheaper, and an arc/stick welder would be cheaper than MIG. When the welders get bigger, you also have to think about electrical service and make sure it's on its' own circuit. If you would like to learn, most colleges offer continuing ed courses.

For a project like this (and what I'm thinking for my Givi rack adapters) and to get a good idea, the best thing to do is to find the right welder/machinist, get talking to them on a slow day, and go over ideas.

Heating to the right temperature would re-crystallize the grain of that aluminium, sure. But most aluminium is heat treated (if it's 6061, it probably has a T5 or T6 heat treatment) and you could destroy that if you take a torch to it. I'm also not sure something like a propane torch would get hot enough anyways. Don't exactly quote me on this - there are dusty textbooks in my basement which have this stuff in them, it's been a while since I learned this... a welder would probably know offhand.

Probably the bigger issue is that the material section is small in general for the design, and there's almost no meat in those corners. The rack should probably be tubular, probably be steel which is more workable and fatigue-resistant, and have fully welded or formed corners.
 
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Welding aluminum with a mig isn't hard once you get the settings right. But it is expensive... Few hundred for the mig, a couple hundred for a bottle, a couple hundred for regulator/accessories and the another hundred plus for a kit to weld aluminum.

Sent from my Galaxy Nexus using Tapatalk
 
beyond what has already been mentioned I'd like add that you have no triangulation to brace the side to side loading. have a good look at a hydro tower next time pass one - there's a very good reason you rarely four members that form a square or rectangle.
 
One option instead of angle stock is metal electrical conduit and a conduit/pipe bender, which definitely still fits into the DIY theme (even cheaper than angle stock, too). I've got a simple U-shaped saddlebag support rack running from the passenger footpeg bolts around back of the rear fender, but you can get fancier. AdvRider.com has some examples if you want ideas.
 
Yup, definitely going to fail before long. That's 6061 aluminium he's bending, he's not reinforcing the corners, and he never radiused the edges of his cuts. In these pics you can kinda almost see the aluminium stress lines where it changes colour right where the bend is.
http://littlesvr.ca/grumble/wp-content/uploads/2012/09/IMG_0719.jpg
http://littlesvr.ca/grumble/wp-content/uploads/2012/09/IMG_0733.jpg

I support the do-it-yourself attitude also, but this one in particular is not a good solution.

I doubt that is 6061, extruded aluminum angle found at big box stores is normally 6063....6061 would only bend about 45 degrees or less before snapping in half.....
 
One option instead of angle stock is metal electrical conduit and a conduit/pipe bender, which definitely still fits into the DIY theme (even cheaper than angle stock, too). I've got a simple U-shaped saddlebag support rack running from the passenger footpeg bolts around back of the rear fender, but you can get fancier. AdvRider.com has some examples if you want ideas.

What a neat tool! I didn't even know one existed, this one definitely goes on my shopping list, could use it around the house too.
 

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