Ideas for building a trailer

Jstude

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Jul 3, 2008
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hi folks, today i started dismembering a small bike for the purpose of using the components as a chassis for a small trailer for my moon dog. It is a small (20 or 24") bike with rear suspension. I just took it apart by separating the bike at the suspension pivot points. At first I was thinking about using two of these bikes and making a two wheel trailer, but now I am thinking about a one wheel trailer. Anyone here made a trailer? Suggestions and ideas welcome.
I have finally taken some pics of my build along with a couple of my other rides.
http://i518.photobucket.com/albums/u346/jconln/HPIM0344.jpg
http://i518.photobucket.com/albums/u346/jconln/HPIM0345.jpg
 

lennyharp

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Jul 19, 2008
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Mesa Arizona
Probably the best wheel to use is wheel chair hubs with a solid mount point on either side.I have used 16" and 20" wheels like this and could use any size. I have used a fork end on either side of the trailer that actually uses a front wheel with stock parts. The advantage of these setups is a lower center of gravity for example using a regular 26" wheel the trailer bottom can be 10 inches or lower by mounting the wheel higher on either side of the trailer.



This trailer is about 20 pounds and will haul 200 pounds as it is 4130 cro moly steel and very strong. with an 8" floor it is also very stable and the axle is on just the sides, the wheels are just 20" front wheels and parts are not special.
 

eDJ

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Jul 8, 2008
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Wayne National Forest
Here's a sketch I made for a rigid mount one wheel trailer. It would be a bit
akward if it were longer than three feet long or so. In this sketch I haven't provided for a hinged spring suspension, but that would be considered if I were to build this.

Ohio allows the motorized bicycle to have three wheels and one rider. The side car makes the most sense of one wheel, but again Ohio says you have to stay within three feet of the edge of the road when operating the motorized bicycle.
So the rigid mount one wheel trailer would make sense here in "The Buckeye State".



By using the front end of a discarded kiddie bicycle with a small wheel the "rake" angle could set the caster of the wheel to follow the turns like a "dolly wheel", much like on the front of a grocery shopping cart and while still providing support to the weight of the load in the trailer. In ohio the trailer would easily fit into the "three feet zone" of the edge of the road and be compliant with the law.

The mounting of the trailer shows two upright tabs that fit over the axle of the rear wheel and be tightened down. At the extended end of the trailer mounts toward the pedal cranks are a pair of hooked plates that attach over the top of the lower frame. Thus with the rear dolly wheel's leverage on the bicycle frame the axle would serve as a fulcum and the clips which hold over top of the lower bike frame would render the mounting solid and stable.

Operating this type of trailer would take some getting used to in tight spaces as it would have a wider sweep than the trailer which hinges at the back of the bicycle on a ball hitch. But in many cases when out on the open road there's plenty of room.

In the sketch you can see there would be room under the trailer's box too. Perhaps a smaller box that would contain a pull out drawer and provide adeqate road clearance could be built there.
 

eDJ

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Jul 8, 2008
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Thanks Lenny for posting that Bob trailer. I hadn't seen it before. As I look at it
I can only wonder how it would handle in tighter turns. Out in the open spaces
I'd bet it would be fine though. I like the suspension on the one in the lower picture as it bothers me having a structure as long as a bike & trailer that's rigid.

When I woke up this morning it came to me how I'd build my suspension and I've yet to create a projection drawing of it to post here. I'll do that later today.

I rendered this sketch to better visualize the layout of the trailing wheel.



I've seen those little kids riding in groups on those tiny kiddie bikes with their Mom's walking behind them. The training wheels are almost as big as the bicycle's wheels. I'm betting the wheels on those little bikes are about 15 inches or so tall.

But for me it's the front end of one of those little bikes I'd like to obtain so I could use it similar to the sketch above.
 

lennyharp

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Jul 19, 2008
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Mesa Arizona
The BOB has a special extra long & strong quick release that mounts the trailer and allows up and down movement so it is not rigid up and down but is side to side. Been too long since I used it for a month or 2 and I don't remember the handling of the unit in turn radius. I am partial to a 30" wide 2 wheel design like my flatbed above. It uses a hyme joint in the hitch and it turns very tight.
 

eDJ

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Jul 8, 2008
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For the design I'm considering this spring & hinge swiveling fork trailing wheel
would support the rigid mount trailer which would likely only extend 54 inches past the rear wheel.



Thus the rear wheel of the trailer would "dolly" like the front wheels of a grocery shopping cart and flex from the hinge mounting. A couple coil springs or bungee could dampen the movement of the wheel while under way. To stiffen the wagon perhaps a cross bar mounted on the upper rear frame with radius arms extending to the top front corners of the wagon box (shown in red) could stiffen it enough to ensure reliability. I don't forsee the trailer carrying a great deal of weight and I would likely carry a plastic weather resistant kids foot locker measuring 36" x 24" x 16" length, width, and depth. From the front axle of the bike to the aft end of the rear tire it's about 54" and the measurment from the aft end of the rear wheel to the aft end of the trailers rear wheel would be about the same 54". (by my calculations) The handlebars of my bike are 28" wide alone. I'm leaving 2 inches of space between the front of the trailer and the back of the rear tire.



In the view at the back end of the trailer you can see the tabs for the
rear suspension to fit into to and accept the rod to establish the hinge. Below it the springs would mount to the trailer and suspension. Since the forks are mounted in bearings and their angle to the ground is such that the rear wheel will turn with the trailers lateral movement the design should be functional.

The red line which extends along the bottom of the bike frame on back into the trailer bed shows the rods that mount rigid to the bicycle frame like the tongue of a trailer. With the upper radius supports (shown in red) I believe it could be viable for going on a road trip. Because the trailer isn't much wider than the bike and rider it would be easy to abide by Ohio's 3 ft from the edge of the highway rule (the zone of operation for motorized bikes) and also conform to the limit of 3 wheels and one rider.

I'm also considering leveling stands on the front corners of the trailer like pop up tent campers use for setting up and that would hold the bike & trailer level when parked. That would add to the usibility of the trailer. I figure the overall length of the bike with trailer would be similar to the length of a bicycle for two.

If I had to travel somewhere I think this trailer system would be more practicle than using a side car. At least that's my thoughts to this writing.
 
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Jstude

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Jul 3, 2008
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South Carolina
Great to see you folks participating in this thread! Since starting it, I haven't been able to concentrate as much as I wanted due to other family obligations. (you know, us older guys have to occasionally do grocery runs, babysit the grandkids, mow the lawn, etc.) I really like the drawings you guys have done. I mainly use the "build and sit" method of engineering. One of my most important tools is a chair. What this means is, I start by gathering some of the proposed components for what I intend to build, lay them out on the ground, and sit in the chair and contemplate the best way to assemble them. Then comes the most difficult part of any job..."STARTING!" After starting, I usually build to a certain point and then "sit" in the chair reviewing what I have done and contemplate the variables and options for my next step. Now that you know a little of my method, I'll let you know what I have done so far. I decided to go with two wheels for my trailer. I saw the one wheel "Bob" trailer and think it's great for a peddle bike. For a motored bike, I'm concerned about having to share the load suspended between the trailer and an already torqued load of a motorized bike rear wheel. On a two wheeled trailer, the load can be mostly carried by the trailer wheels. I dismembered two 24" full suspension bikes and used the rear portions for the two wheel supports. A little creative cutting and welding of a discarded work van ladder rack has provided a good drop axle effect for tying the two together. An old baby crib metal frame has been re-employed as the trailer bed frame. That's where I am so far. Now it is more "chair time" to contemplate the tongue and hitch. Some of the "store bought" trailers attach to the bike's rear axle. Again, I think that's too much to ask of a motorized bike axle that already dealing with two sprockets and a motor. So I am considering a mount that connects to the frame, allows for left, right, up, down and yaw (lean) articulation. All this has to be accomplished without building something too heavy and yet strong and durable. I have a picture or two in my camera. I'll share that with you as soon as I figure out how to do it without transferring all 128 pictures on the camera. For now, it is way past my bedtime! Even the poodle wants the lights out.
 

Jstude

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Jul 3, 2008
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South Carolina
Here is a picture of my trailer build so far. I have an old plastic baby seat that goes behind the seat on an adult bike. I think that the metal support frame for that seat will make a good start for a "frame mounted hitch" for the trailer. However, in order to use mount the hitch, I'll have to take off the package carrier and bag. Now for some "chair time" and a slice of fresh watermelon while thinking about my next move.

http://motorbicycling.com/attachment.php?attachmentid=1910&stc=1&d=1218398019
 

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eDJ

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Jul 8, 2008
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I like that outfit Stude. I'm always fascinated with taking things that are already laying around and working them into new solutions...especially in a way that has people asking why they didn't think of that.

Why Ohio won't let us have more than 3 wheels ??? :rolleyes: It would be so much easier to build a trailer like you have going.

When I was looking at that outfit just now I thought of a detachable braced loop that would extend out behind the rear wheel with a "Pentel hitch". The trailer could have a short tongue with a ring welded to it's end to hook into the small Pentel hitch. When done with the trailer the hitch to bike adapter could be stowed in the trailer. I've seen some small Pentel hitches on lawn tractors that would lend themselves to this.

Just my thought. ;)
 

Jstude

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Jul 3, 2008
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South Carolina
thanks for your input eDJ. I will probably work on using the baby seat frame tomorrow. The braced loop you suggest would be OK some how attached to the rear axle but I am reluctant to push that area due to the stresses of the motor. I plan to attempt at least a 3 point frame connection higher up on the bike. I have one pretty unique idea for the main connection for a trailer hitch. If it works, I'll share it with the rest of you. If it don't work, I'll do something different and claim that it was the unique idea anyway! Happy trails folks.
 

lennyharp

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Jul 19, 2008
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Mesa Arizona
Looks like you have made progress with the build. It looks like you have it wider than I have built in the past. I usually build around 30" wide at the wheels. A thought about the hitch is to use the rack to mount a hitch to. Keeps the tongue short. I have used hyme joints for my hitches usually. Here is an image and one for sale at .... Discount Karting
 

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eDJ

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Jul 8, 2008
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Stude, It seems I notice people mentioning their concern for the stress on the axle with these Chinese motor kits. I'm wondering if a stronger material exist or a stock bolt could be made into a servicable axle. Perhaps a longer grade 5 or 8 bolt cut off and a thread cutter used to chase the threads after the cut end is ground to a bit of an angle. In Ohio we're only allowed to ride at 20 mph legally
and it makes me wonder if the BMV has considered the axle strenght issue when calculating that speed limit.
 

lennyharp

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Jul 19, 2008
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Mesa Arizona
The law makers are not engineers and there is no engineering principle that says a bike axle has to be weak. A quality piece of steel 4130 cro moly or stainless will hold up to all probable stresses involved in 30 to 40 mph use. Road bike racers hit speeds in excess of 60 mph coming out of mountains. The bikes are lighter but that speed is a lot greater and the axles are hollow quick release axles.
 

Jstude

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Jul 3, 2008
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South Carolina
My main concern about the axle mounting point has more to do with how "busy" do you want that area to be? I just don't want all the activity concentrated in that area. As far as the state of Ohio considering "axle strength on bicycles"... Is this the same state that says that cars can fly down the interstate at 65MPH while trucks must maintain 10MPH slower speed on the same road? I've seen some pretty nasty results of the misjudgment of "closing rate of speed" due to this well intended law. Once I have my sprockets aligned and my axle torqued down properly, I just don't want to mess with it. As to width, I went with the 26-3/4" width of the baby crib frame since it was straight and square. every thing else to accommodate that gives me about 40" of over all width. If that turns out to be a problem, I have a saws all and a welder!
 
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D.J.

Member
Jan 20, 2008
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Canada
Ok , no one has mentioned exterior design . This is a link to the teardrop and tiny travel trailer design page .

Teardrop and Other Trailer Designs


I like to make things look like something else .




This kind of trailer has been made to tow behind cars for years . One made out of a vintage pedal car to tow behind a bike would be cool .


 

eDJ

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Jul 8, 2008
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Wayne National Forest
LOL ya just gotta love this place.

That's hasta be the best use for a pre 65 Corvair I've seen yet.

As for Ohio's law makers, I think they write up a bunch of stuff and stand back pitching their pencils at all of it like darts. Whatever is hit becomes law.
Just today I was listening to the news report of Diebold's paperless election machines and the law suit they are in. Talk about a nightmare.