Need help choosing material

Gary_in_Indiana · Apr 3, 2003

I'm looking to build a motorcycle dolly and looking to figure out what thickness of material I ought to use. I'd like it to be able to accomodate the largest of touring bikes as I have a big bike now (Honda Goldwing Aspencade) and am hoping to get a newer one (1800cc) as well.

For a picture of what I'm looking to build just click here. I'm sure it's some lighter weight metal than I'll be using but such is the trade-off for wanting to do it myself. /forums/images/graemlins/smile.gif

In any event, I'd like some input as to what thicknesses of steel would be the minimum I could use to do the job as I'll probably need to lift and carry this thing as well and my back isn't what it once was. /forums/images/graemlins/frown.gif

wroughtn_harv · Apr 3, 2003

Morning Gary,

It looks like the channel is just formed and out of fourteen gauge. You can get those pieces done at any decent metal shop with a big brake.

I really don't like the concept of the one inch sliding in and out of the one and a quarter inch tubing like they use. If I was you I'd consider a folding one and a half inch eleven gauge minimum.

The principle involved is you want the axle to be as wide as possible for stability. There are two ways to get this spread. One is to have one tubing slide inside of another. Another would be to have the piece hinged so that when it's put away it takes minimum space. But when it's set up for use you have maximum strength and spread.

Gary_in_Indiana · Apr 3, 2003

I like the idea of hinging so I'd just have to pull a couple pins to fold it up when I'm done. /forums/images/graemlins/smile.gif

I'll have to put a little thought into how to design it as I don't want to give up any strength. The whole thing will get bounced around pretty good during the loading process. It'll have to roll over the back edge of my trailer and then over the car dolly platform at the rear of it.

Anonymous Poster · Apr 3, 2003

2 questions come to mind, first, why would you ever want to carry something that has wheels on it, and could easily be set up with a handle? My wife has a suitcase she tows all over airports with no problem, and she has loaded it sufficiently that I've considered a crane to load it into the Blazer.
Second question is do you really NEED the collapsable features that are built into that unit so it fits into the compartment of a wrecker? If you don't need to collapse the unit, a lot of weight could be lost by using diagonal reenforcments to replace member strength.

Gary_in_Indiana · Apr 3, 2003

There are a couple of difference between this and your wife's suitcase. First, to have this roll around behind me like that I'd need it would need an extendable handle just like her suitcase. Also, I'm not looking to move this thing around nice, smooth, level surfaces as one would find in an airport. I'll be on dirt, grass, gravel and whatever else where the wheels would be little or no help out at my barn, etc.

As to needing the collapsable features, I'm not sure I do or don't. In point of fact I do have a couple of 8" x 18" x 28" toolboxes on my trailer which I could carry this to or from where I need it. Alternately, it would be a lot easier to store away from my trailer, too.

You make an interesting point about the trade-off between portability and weight. It might be possible for me to design something which will incorporate both portability and use diagonals I could hinge on one end and pin on the other.

Anonymous Poster · Apr 3, 2003

Gary, you have no IDEA where 1 short woman can haul a wheeled suitcase with 2" skateboard wheels. I doubt any man could drag that thing where she does.
One of the nicest materials for this type of device is the Perforated Angle Iron Steel City makes for electrical construction. The 2 x 3 size would give you a 6" wheel cross section. The stuff is high carbon, and very strong in comparison to weight.
For off road wheeling, you probably want at least 6" wheels, and a removable axel made from pipe would provide max knock down capability. The axel could have a center flange that was held to the tire boot with 3 or 4 bolts. It wouldn't provide the assembly speed of the towtruck unit pictured, but the tradeoff might make it worth while.
You might also want to look at junQue grocery carts usually found in the grass along interstates for wheels if you have anything resembling a stable surface to roll on.

Gary_in_Indiana · Apr 3, 2003

I think I'm just going to go with conventional steel for this project. That high tech stuff sounds neat enough but I'm not out to build a better unit here. I just want a serviceable one. /forums/images/graemlins/smile.gif

Another factor is cost. That material you mention doesn't sound cheap. I can buy surplus steel at fifteen cents per pound. If I end up with mine weighing in within 10% of what theirs weighs I shouldn't have more than $8.00 in the steel. Some nice wheels and some hardware by the pound at TSC and I'll be all set. Something under $50 for everything would be my estimate.

I'm going to do some sketching tomorrow and see what I might be able to come up with. In reality the only time I'll be using it loaded would be from my place into the shop if it's dead or if I somehow lose front and rear brakes at the same time. Other than that it'll just collect dust in the barn.

That's one reason I still want the break down capability. That way I can easily store it up and out of the way rather than have it taking up floor space. If it's too heavy I guess I can always make a second trip to carry the pieces to or from my trailer. /forums/images/graemlins/smile.gif