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There are plenty of other great bicycle trailers on Instructables, but I thought I'd post my own. Some of the key points: no welding is required for this trailer, and it is built (mostly) from items from Home Depot and spare bicycle parts.

This trailer was built over time, with a couple of iterations. A few times in this Instructable, I'll use the phrase, "Ask me how I know..." Most of these lessons were discovered during failures of the trailer on the road... these were cases when "the wheels coming off," is more than a figurative phrase.

Also, I make no claim that my solutions to these problems are the best or only way of solving them. However, in the spirit of Instructables being "open-source hardware," feel free to choose, mix, and match these solutions to your favor.

Step 1: Overview & Anatomy

There are several portions of this instructable, so I'll start with an overview of the steps and the parts of the trailer.

Main body: the body of the trailer is a plastic bin with a lid; I used an Akro-Mils Nest & Stack Tote (NST) Model 35300 (29 1/2 x 19 1/2 x15)--I bought mine at Grainger. I like it because it is pretty intrinsically strong and stiff. However, I think this plan can be adapted to most plastic bins.

Wheel mounts: the wheels are mounted to metal brackets on the sides of the container. They are adapted from brackets from Home Depot, with some cutting and drilling.

Internal Structure: the plastic bin is not strong enough to support the wheels (ask me how I know), so an internal frame is needed to hold everything together. It connects the wheels to the bin, and the bin to the trailer connection.

Hitch (trailer side): to connect to the rear wheel hub, the hitch needs to take a right angle and come in at roughly 45 degrees to the axis of travel. Therefore, when you make a turn in one direction, the hitch comes in roughly parallel to the rear wheel. There is a flexible coupling (rubber tubing) to allow turning. The connection to the rear wheel is made using an air hose quick-connect.

Hitch (bicycle side): the connection to the rear wheel to the trailer is made out of a metal bracket with an angle that matches the hitch, which remains semi-permanently in place on the bicycle (you can remove it, but you will need a wrench). It doesn't add much weight, so I leave it on all the time.
I love it
<p>Nicely done, Bats22. Perhaps using a heim or ball joint in series with the quick-connect for the hitch would eliminate unwanted lateral and vertical flexibility. Also, since you're already penetrating the bin with two lengths of conduit, adding a third for a through axle would only give up another 1 1/2 inches or so while adding stiffness and parallelism to the wheels.</p>
Very well done, kudos on the airhose connections! Cool.
Great Trailer! Excellent Instructable!<br/>For those who may venture into either making a trailer or buying one, may I recommend new trailer users need to practice on a quiet traffic free road.<br/>Please remember:<br/>Bikes for pulling trailers need good brakes.<br/><br/>Load the trailer as close to the axle as possible, keeping the centre of gravity (c of g) slightly forward of the axle.<br/><br/>Keep the load as low as possible. <br/><br/>Secure the load properly so it cannot move.<br/><br/>Please keep your speed down.<br/><br/>Think ahead and brake early and slowly, avoiding harsh braking. <br/><br/>Do NOT use the rear brake. (To avoid jack-knifing).<br/><br/>And keep your speed low. The heavier the load, the slower the tow. For a reasonably heavily laden trailer, keep the speed to NO MORE THAN 10 mph.<br/><br/>Handling problems<br/>Trailers follow a tighter turn radius than the rear wheel.<br/><br/>Making S-turns will almost certainly capsize a trailer.<br/><br/>Trailers can roll, especially when turning and braking, or when turning too fast, or turning and the inside trailer wheel hits an obstacle or a pothole, or turning combined with adverse camber, or turning and an improperly secured load.<br/><br/>Keep the centre of gravity as low as possible and forward of the wheels. Weight too far rear can lead to pitching and yawing, rear-wheel lock-up during braking and consequent jack-knifing and loss of control. To reduce the chances of jack-knifing, DO NOT USE THE REAR BRAKE.<br/><br/>Tyres need to properly inflated, soft tyres can lead to speed wobbles yawing and rolling-over.<br/><br/>Take care to ensure that the wheels are parallel, or the tyres will wear excessively. Excessive tyre wear is a sure indication that the wheels are not parallel.<br/><br/>The hitch featured here will remain attached to the trailer even when the trailer has rolled. This could have serious consequences in traffic. My trailer has a hitch which de-couples when the trailer rolls-over. My commercially made trailer is a 'Der Roland' and I would definitely NOT buy another Der Roland or similar type if I needed a replacement. <br/><br/>The Der Roland trailer can be seen here <a rel="nofollow" href="http://www.bikesandtrailers.com/bike-trailers/roland_roland.html">http://www.bikesandtrailers.com/bike-trailers/roland_roland.html</a><br/><br/>If looking for new trailer, I would look for a two-wheeled type, rear axle hitch, wide track (the distance between wheels) and a load platform as reasonably low as possible. In-fact virtually identical to the trailer presented in this Instructable. My only DOUBTS CONCERN THE HITCH which will cause the trailer to remain attached to the bicycle after the trailer rolls-over, which is inevitable and may cause the rider problems in a number of circumstances, assuming that the trailer is fully-laden when it happens.<br/><br/>If you hear banging, IMMEDIATELY brake slowly and stop in a straight line. Probably caused by an inadequately restrained load, under inflated tyres, too high a centre of gravity (c of g). The banging sound lasts only a few seconds and IMMEDIATELY PRECEDES A ROLL-OVER. The banging noise is caused by the wheels of the trailer alternately lifting off the ground and crashing back down.<br/><br/>On even a slight almost imperceptible slope, a laden trailer can easily topple a bike off its kick-stand, or pull it away from a leaning-point. Consider chocking both trailer wheels, before loading or unloading. <br/>
I found i want to do all of those now and put it in the forums as pictures.
Thanks!
I saw, if a wheel falls off my trailer, and i'm on the trail, i'm gonna put it on as good as possible and keep riding.
totally_screwed gives a lot of useful advice about trailer towing, but also some I must disgree with (having been a heavy trailer user for a few years - I'll post my design on here sometime: It has proved good enough to carry 75Kg of sand, 2 students, lots of concrete flags etc). Firstly it's the _front_ brake you need to be careful with to avoid jacknifing. Heavy front braking with a heavily-loaded trailer can lift the rear wheel enough that the trailer shoves it sideways (this is quite exciting!). The advise about sensible speed and thinking ahead is imporntant - it amazing how much extra braking distance you can need with a big load. Secondly I disagree with the 'hitch should disconnect if trailer falls over' thesis, although to be fair it may depend on the trailer design in how low it's CofG is. In my experience, a heavy trailer will not fall over (or at least mine won't). It only tends to fall over when it's quite empty and bounces around - road humps are the biggest problem. When it is trying to fall over, having a hitch with a limit that brings the trailer back level again is much more useful than one that just lets go (potentially putting the trailer arm into your wheel (I've had that too - not good). This centering aspect is just one of many to consider when making a hitch - stength, hunting, rigidity, bending, sufficient yaw, pitch and erm 'the other one', (but not too much yaw), quick release, ease of construction, cost. Good trailer hitches are hard to make. I'm on my third design (using a car steering ball-joint) which works very well indeed but is a pain to make the bike half of. I like the various designs detailed here - some good ideas.
I used this idea, with a castor wheel bracket and a little welding to make a nice trailer hitch attachment for my stereo trailer. Sorry the pics are not so good but you get the idea.
Ctrl-F "Ask me how I know". Next... Next... Next... Next... I'm so happy about that :D The air hose quick connect is a great solution to the problem of rotational freedom- if I had half of this stuff available I'd probably make one. Interestingly, in the Cambridge this side of the pond a lot of people have similarly sized bike trailers they transport young children in- I guess it's a great solution to traffic/pollution/global warming etc. but I'm not sure I'd trust my 3-year-old child to a tiny trailer with no roll cage or seat belts that's probably very easy for 4x4 drivers to not notice.
yea
Thanks! :) I'm always glad to help people learn from other peoples' mistakes.... including my own. I see lots of folks with their kids in cycle trailers in the (newer) Cambridge, where I work. It does seem a bit scary to me, but I admire the concept... and I figure the kids will have some fun early memories of zooming along the road. Enh... not having kids, I don't have to work out that risk/reward balance.
Hey, thanks for the info on how to lock the wheel that unscrews itself. I was wondering about the best way to solve that problem.
A good stability idea would be to put a second hitch on the other side of the bike, and bring them together with a U-Joint. I like the quick connect idea. You could probably put a universal ball joint on it, and use the quick connect to attach to the hitch from there.
I like it. I was just shopping for a bike trailer so I don't have to take my car to the grocery store. Man they are costly, $400 or so, geez. This one you made looks cool. I like the giant wheels.
I'm looking at adapting something like this for my wife's scooter. I'd add rear visibility lights to the rear, with wires running along the underside to the scooter. The scooter itself has some connectors for the back lights, presumably for just such a thing (my luck!). ~adamvan2000
I like the rubber hose with spring and hose quick connect idea because the rubber hose allows pitch and yaw while the coupling allows roll and the spring reduces lag and catchup. However, while I retained the coupling idea I replace the hose with a 2&quot; caster wheel by cutting parallel flats on the wheels and bolting the wheel to the frame using the 1/4&quot;-32 threaded fender mount holes. An angled bracket is then bolted between the caster and the conduit. <br/><br/>Another modification was to not loop the conduit but to use only one 45 degree angle so that u-bolts could be used to fasten to the trailer and allow adjustment for wheel height in order to achieve a level trailer. When tightened the u-bolts hold good enough to keep the trailer level. A hole can be drilled through the conduit once the height is adjusted but was not necessary even with a 200lb load. I did a completely different deal to get pitch and raw by using square tubing with the coupling still used for roll. Pictures won't upload here, had to add links. Instructable later maybe. Good work.<br/><br/><a rel="nofollow" href="https://www.instructables.com/file/FZULNJTF9AC3KOI/">hitch wo/roll control</a><br/><a rel="nofollow" href="https://www.instructables.com/file/FQZQTLQF9AC3KOH/">u-bolt leveler method</a><br/>
nice.
Great job. I am trying to find out and learn more . My trailer is still working great but I will build more. How much weight can this wheel connection take though? +- please let us know max weight and also weight it takes with ease. Thanks
Thanks for the nice comment! I'm not actually sure how much weight this trailer can take. Given how many times "ask me how I know" comes up in this Instructable, I don't particularly want to do a "max load" test that has a risk of making the wheels fall off (yes, again). That being said, I'd guess it could take around 75 lbs safely. This is based on my being able to balance most of my weight (160 lbs) on the axle, and nothing seemed about to fail. However, a static test like this has much different results than a dynamic test. For instance, the loading that comes from riding over a pothole with a full tub would be much higher. If I end up doing a 'bike pull' (i.e., like a tractor pull), I'll post how much was in there.
Nice work sparkie! Your probably still getting a little flexing thru your axle assemb. that is giving you the tracking issue. I have found that using a solid axle like a piece of 1/2 or 3/4 rigid emt with perfectly cut perpendicular ends does nicely for hauling weights up to 100 lbs. A solid axle mounted under your rig would also bring it up level and ease the strain on your connection point. Great job on the presentation!!!
Great instructable! Nice job incorporating all of the problems that arose. This is definitely on my list of projects now. Thanks!
Very nice instructables! Good pictures, well detailed. I know there are already a bunch of the trailer instructables, but more the better. I really have to make myself one of those!

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Bio: Building energy efficiency/construction industry consultant; woodworker; casual (not hard core) cyclist.
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