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donkpow

Ontogenesis

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The trailer. This is a collection of most of the major components. The tubing is scrapped from a steel bed frame, cleaned up a bit. The "floor" is scrapped from a shopping cart. There will be bending, welding, bleeding, cursing, etc. before completion.

beginnings.thumb.jpg.6cc1ea0d8d9e01745825f6d3f33f7d11.jpg

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Neat! I look forward to the project updates.

That does seem like a mighty large wheel, though.  Any reason why?

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1 hour ago, Razors Edge said:

Neat! I look forward to the project updates.

That does seem like a mighty large wheel, though.  Any reason why?

It's a 26" wheel. I asked myself, why do they always use a little wheel on these trailers? I couldn't surmise a good technical reason. I am hoping that a higher wheel center will help the single wheel trailer stabilize itself. The deck of the trailer will now be below the center of the wheel and will have to be lifted, first on one side then the other, in order to wobble side to side around that center axis. I also plan to put a rack on for panniers.

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19 hours ago, donkpow said:

It's a 26" wheel. I asked myself, why do they always use a little wheel on these trailers? I couldn't surmise a good technical reason. I am hoping that a higher wheel center will help the single wheel trailer stabilize itself. The deck of the trailer will now be below the center of the wheel and will have to be lifted, first on one side then the other, in order to wobble side to side around that center axis. I also plan to put a rack on for panniers.

Doesn't a larger wheel mean a longer trailer?  Assuming it is a standard "Bob" flat platform with the wheel at the back, the trailer would add to the overall length, and I can't imagine longer is "better". This Bob uses a 16" wheel.

bob-yak-bike-cargo-trailer-main.thumb.jpg.3e789c4aa45b8e3a74239a5be5cf6db8.jpg

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Although, you could go with a sort of cargo bike/Bob hybrid platform where the platform skirts the wheel:

IMG_8138.thumb.JPG.11d083aa9e3fcd22c960c5d051e536d5.JPG

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I want a longer trailer than I have, at least a bed that is longer than I have. I want it to fit a larger bin. The rear wheel will have a rack over it and the rack will hold the panniers. Single wheel trailers have stability issues when heavily loaded.

The difference in length between a trailer with a 16" wheel and one with a 26" wheel is about 5". The point that is important for design consideration is the center of the wheel.

With a trailer bed that is in the same horizontal plane as a horizontal line through the rear axle, you can see how easy it is to rotate the bed along this centerline. If the bed is parallel but lower than the axle line, you will have to swing the trailer bed up rather than just rotate it. Which means you have to lift the weight of it. That's my thinking any way. 

extrawheel-Przyczepka_02_26-40-1024x1024.jpg

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1 hour ago, donkpow said:

extrawheel-Przyczepka_02_26-40-1024x1024.jpg

This contraption looks superfluous.  If you need a rack for panniers, put it on the bike. No need for an extra trailer just for a rack!

Clearly, though, not what you are planning on building as you have that grocery cart stuff to use.

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13 minutes ago, Razors Edge said:

This contraption looks superfluous.  If you need a rack for panniers, put it on the bike. No need for an extra trailer just for a rack!

Clearly, though, not what you are planning on building as you have that grocery cart stuff to use.

Right, okay. My concept is to combine the third wheel concept with a single wheel trailer and create a premier grocery getter. Leave the panniers on the third wheel so I don't have to constantly take them on and off the bike. The panniers I have for grocery getting are a large size, volume wise. I could then buy a smaller size of panniers and just leave them on the bike for more common purposes like carrying found cell phones home. Don't need the capacity of a trailer for that.

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21 hours ago, donkpow said:

Right, okay. My concept is to combine the third wheel concept with a single wheel trailer and create a premier grocery getter. Leave the panniers on the third wheel so I don't have to constantly take them on and off the bike. The panniers I have for grocery getting are a large size, volume wise. I could then buy a smaller size of panniers and just leave them on the bike for more common purposes like carrying found cell phones home. Don't need the capacity of a trailer for that.

Got it.  A sort of easy and ready-to-roll option for a big shopping day.

How does the shopping cart piece play into your design?

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7 minutes ago, Razors Edge said:

How does the shopping cart piece play into your design?

The shopping cart provides the wire mesh floor for the trailer. 

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Just now, donkpow said:

The shopping cart provides the wire mesh floor for the trailer. 

I think we need your design sketch so we can see what you have in mind.

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Just now, Razors Edge said:

I think we need your design sketch so we can see what you have in mind.

I thought you were angling for pictures. :lol: It will look something like the Bob trailer above except with a big wheel.

I've got the drawing for the trailer tongue drop outs.

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53 minutes ago, donkpow said:

I thought you were angling for pictures. :lol: It will look something like the Bob trailer above except with a big wheel.

I've got the drawing for the trailer tongue drop outs.

Yep.  Pictures are good 👍

But you are angling for the Bob above plus a rack for panniers over the rear wheel, correct?

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20 minutes ago, Razors Edge said:

But you are angling for the Bob above plus a rack for panniers over the rear wheel, correct?

Something pretty close to that.

I thought I had some 3/16" steel for the tongue dropouts in the garage. Apparently not. It is only 2" wide. I need bigger. I also need some 5/8" OD steel tubing to reinforce the butt joints in the frame. I don't know if the steel guy has the tubing. He might have 5/8" round stock. I still need to get welding wire. This type of thing is not totally "free".

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Here's the sketch on the tongue dropouts. I have to fit the existing special purpose skewer that I currently use for a trailer. Tubes come in from the left and get welded to a steel plate that then slips over the skewer. The dimensions are assigned to accomplish functionality and compatibility. I'll refine, if needed, when I make it.

dropout.thumb.jpg.c4aed2635b8d7e60b9dcf088f79b4239.jpg

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3 hours ago, donkpow said:

Here's the sketch on the tongue dropouts. I have to fit the existing special purpose skewer that I currently use for a trailer. Tubes come in from the left and get welded to a steel plate that then slips over the skewer. The dimensions are assigned to accomplish functionality and compatibility. I'll refine, if needed, when I make it.

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Interesting.

I know our Burley uses a simple attachment that seems to work well.  At $8, it seems a reasonable option for you to consider, but perhaps is not up to the spec you need for your trailer? 

 image.png.8993f974587f7f187b87e6b09c1a1d48.png

Conceptually, a rack mounted "hitch" like a fifth-wheel might be an idea to consider.

image.png.02cfef125c1bcb919610f8a4b3f95568.png

Finally, the "add-a-bike" sort of seatpost linkage seems simple as well:

image.png.e310b67a3d8098e437f11c51ddeca022.png

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Over the years, I have considered all the designs I could find. Each type has merit. I liked the single wheel trailer. It doesn't carry as much weight as a two wheeled trailer but it tracks much better. Tracking becomes a major issue in some conditions. Speed also influences each design differently.

It makes sense to me to attach the trailer at the rear axle. There are several reasons for that, IMO. One is you can't get much more direct coupling to the power train any place else on the bike.

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I went up the hill to my steel supplier and brought home some steel for the project. 3/16" x 3" x 12" flat stock and a couple of feet of some steel tubing with the outside diameter of 5/8".  $5.00 including $1.00 charge to cut the piece of flat stock off a 20' stick. He charges by weight on new steel. Over the years, I have purchased all kinds of stuff from him. I bought a lot of used steel when I was working on the old bulldozer. This is little pieces for the trailer.

You can see I have begun to trim the pieces for the dropouts. Both sides need to be identical so I'll be working them together after this point. The remaining 6" of the flat stock will be used as brackets to attach the trailer to the tongue. I don't need to worry about that right now. I'll work the tongue, trailer bed, and rear triangle separately. Then I'll put together the assemblies and finish some details. The pieces of round tubing will be used to reinforce joints in the trailer bed frame. The bulk of the trailer frame is made from cheap steel tubing (metric dimensions) and I don't know how well it will take a weld or even cope with stresses. I don't have long pieces of tubing so I have to piece together what I have. You'll see how this works as I go along.

pieces.thumb.jpg.bbc2165a5c786ab6e9398869095db58e.jpg

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Bending some of the tubes, getting a feel for operations. It seems the tubes may be a little too soft for this job. Chromoly they are not. I may have to adapt the design to support the mushy tubes. The red handled tools are tubing benders.

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The essence of the construction. That's all there is, bend it and weld it.

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Bend a little. See how much spring back there is.  Bend a little more.  Oops.

 

From "The art of jake bending."

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21 hours ago, donkpow said:

The essence of the construction. That's all there is, bend it and weld it.

Neat.  Still looks like that is gonna be a LONG trailer - 5' to 6' or so? 

Definitely keep the pics and progress reports coming :D

I wonder if the cart/floor will help stiffen up the tubing when it is welded together. The tubes feel flexy now, but will not when welded in place. Maybe cross bracing under the floor would help?

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Yeah, the floor should help. My original idea was to use two pieces of square tubing to go from the back wheel straight to the tongue connections. This tubing came along so I changed the plan, as it was. The bed of the trailer will be 2' long. Back triangle will place the axle about 15" behind the bed. The tongue/fork is another 16".  Doing the math, ... uh,  ....

👨‍🏫

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🧙‍♀️

looks like a little more than 4' from the bike axle.

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15 hours ago, donkpow said:

Yeah, the floor should help. My original idea was to use two pieces of square tubing to go from the back wheel straight to the tongue connections. This tubing came along so I changed the plan, as it was. The bed of the trailer will be 2' long. Back triangle will place the axle about 15" behind the bed. The tongue/fork is another 16".  Doing the math, ... uh,  ....

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👨‍💼

🧙‍♀️

looks like a little more than 4' from the bike axle.

16" + 24" + 26" = 66" (5' 6").  Am I wrong?  Tongue/fork, bed, rear wheel.

But awesome regardless!

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14 minutes ago, Razors Edge said:

16" + 24" + 26" = 66" (5' 6").  Am I wrong?  Tongue/fork, bed, rear wheel.

16" would include the radius of the rear wheel of the bicycle.  I've set the clearance around the wheel to ensure the fork of the trailer clears the fender. As far as overall length, you should probably consider the "wheelbase" dimension. That's the one that really counts.

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Here is some advancement on the trailer tongue dropouts. In the first photo, you will see that I have welded the two pieces together. This allows me to work the two together, essentially creating two identical pieces.  Not completely exact but I can make effort in a couple of key areas to produce matching pieces. In this case, you can see I have drilled the hole through two pieces at exactly the same distance from the 'top' of the dropout. You can do this with a lot of materials. Glue them together, tape them together, whatever works. (hot melt glue works good)  Perform your operation and separate the two pieces. Here I'll have to grind away the sloppy little welds and wedge the two pieces of steel apart and clean everything up. I've still got some cutting I want to do on these pieces before I continue.

side.thumb.jpg.2d9fd4fc8a8236ac95ad9a90d26426ee.jpg DO.thumb.jpg.54168752458cfa27c76aed7f9b8be702.jpg

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On 10/31/2019 at 11:14 AM, donkpow said:

Here is some advancement on the trailer

Any updates from over the weekend?

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15 hours ago, Razors Edge said:

Any updates from over the weekend?

I haven't put together any 'official' updates, I did make some advancements. The frame for the floor is fit up. This is proof of concept on the technique to be applied for other components. I was in and out all weekend trying to find my way through construction of the tongue. I tried a couple things attaching that tubing to the tongue drop outs. It's not real clear how I am going to do that. I experimented with that, hammering the tubing but it looks like that is not a good method. Likely I'll slot the end of the tubes and trim them to fit. I built a little "v" block for the drill press. I need to center the slots on the end of the tubes so I settled on some drilling and needed the "v" block jig. I also cut some plywood to act as a jig for the angles of the toungue arms.

You see, I don't have clarity in this phase. There is contemplation, experimentation, searching solutions, prep work, etc. It is likely I will have similar phase when I get to the equally complex rear triangle. I know what I need to make the trailer but I don't know all the details on how to get there.

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6 hours ago, donkpow said:

I haven't put together any 'official' updates, I did make some advancements. The frame for the floor is fit up. This is proof of concept on the technique to be applied for other components. I was in and out all weekend trying to find my way through construction of the tongue. I tried a couple things attaching that tubing to the tongue drop outs. It's not real clear how I am going to do that. I experimented with that, hammering the tubing but it looks like that is not a good method. Likely I'll slot the end of the tubes and trim them to fit. I built a little "v" block for the drill press. I need to center the slots on the end of the tubes so I settled on some drilling and needed the "v" block jig. I also cut some plywood to act as a jig for the angles of the toungue arms.

You see, I don't have clarity in this phase. There is contemplation, experimentation, searching solutions, prep work, etc. It is likely I will have similar phase when I get to the equally complex rear triangle. I know what I need to make the trailer but I don't know all the details on how to get there.

👍   👍   👍   👍  

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Trial and error on the tongue dropouts. I need to be fairly accurate and avoid weakness in this area. Here's what I did last week. The strength of round tubing is in its roundness. Here I have flattened the tubing creating weakness. It was an experiment to see if I could hammer a strength element into the tubing but flattening it to facilitate welding. Fail:Image1.thumb.jpg.93756c8459ffa45b522234ea866933f4.jpg

 

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Here Is a different approach with a piece of scrap. A little crude but on the right path.

Image2.thumb.jpg.145cbf564ca0a932bec43fe09d002a18.jpg

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Today's test with a spare tube of the correct diameter. Not too bad. Any deficiency is the result of my lack of skill. I am not a surgeon, after all. I had hoped to set up a jig so that I could get accurate results easily between the four pieces. That didn't work so I have to lay all four pieces out by hand. Basic cuts with a cutoff wheel and grinding wheel in a portable grinder. Then touch up with hand files. I could probably set this up for a somewhat automatic manner and get some consistent results but I'd end up spending more time building the machine than simply working these by hand. Same for the future when I have to notch the tubes.

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Image4.thumb.jpg.9e760b5771db93420fc885d22afd362e.jpg

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Here we go. I'll need to trim and fit the pieces together then do some welding. The dropouts need to be centered in the tubes on the same plane.  This is the general idea.

Image5.thumb.jpg.b441ba209d6f917fee81897226d45c63.jpg

Image6.thumb.jpg.696650487050107eee4fe0b61b8582ba.jpg

 

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I like where this is going.  Seems like you're figuring it out.

Have you test fitted the drop outs into the rear wheel already? Those seem a little thick when used together, but I'm assuming a normal QR works with them???

Also, are the two tubes going to run parallel to each other and the rear wheel and connect to the trailer body at a 90o angle? Will the be some sort of angled brace? Or are you  doing a u-turn with the tubing like the one below?

image.png.31d527c7a327c2a41d8aa99f080e7a3b.png

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The drop outs fit the special QR skewer I am using for my current trailer. Not too thick, not too thin. Just right.

While I am building something very similar to the Bob tongue above, there are some differences. I am using four tubes instead of two because my tubing is scrap and none of the pieces are long enough to do the job as pictured. It would be easier if I could use just two tubes for the job. Certainly maintaining angles would be easier. My tubes go straight back from the dropouts and make a 90° turn into the central pivot of the tongue. The 'tilt' of the pivot off of vertical is the result of the two tubes being the same length from the rear axle. I don't believe I will need any bracing in the tongue.

The central pivot is interesting in how it functions. As far as I can see, applying weight to the trailer pushes the bottom forward and pulls the top back. My pivot is less than 10" long. I expect its connections will need to be more robust than those in the Bob trailer tongue.

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Hey nice work. I didn’t know you were back on this project because you started a new thread. I don’t have the patience to build something like this. When you were talking about your tubes being s little soft I would suggest stitch welding a bead of a better grade of steel along the bottom of the tube. I used to do that with tongs that were made with crap steel to strengthen them and stiffen them up.

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1 hour ago, Longjohn said:

Hey nice work. I didn’t know you were back on this project because you started a new thread. I don’t have the patience to build something like this. When you were talking about your tubes being s little soft I would suggest stitch welding a bead of a better grade of steel along the bottom of the tube. I used to do that with tongs that were made with crap steel to strengthen them and stiffen them up.

Yeah, it takes forever and Razor's Edge is not known for his patience. ;)

Thanks for the tip.

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16 hours ago, donkpow said:

Yeah, it takes forever and Razor's Edge is not known for his patience. ;)

Thanks for the tip.

Mostly I'm just excited to see how this project goes!  It is nice to see actual "bike" stuff discussed her, and this thread is both bike related and interesting!

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1 hour ago, Razors Edge said:

Mostly I'm just excited to see how this project goes!  It is nice to see actual "bike" stuff discussed her, and this thread is both bike related and interesting!

I could probably put it all together in a day or two if I really went at it. That kind of takes the fun out of it. Take it slow and discover new things as you go, maybe make it better. Stuff like that. I've been looking at the pivot. I didn't get the dimensions right so I have to refigure the angles and whatnot. I'm trying to decide if I want to recut the plywood forms to fit the new angles or just wing it.

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