Bicycle Trailer.




this is the finished bicycle trailer. I built it principally because i had all the components lying around and needed a bicycle trailer. many substitutions for the different parts are available, so this is more of an overview and general conceptual how-to on building bicycle trailers.

Step 1: Plastic Bin and Crossbeam

I had this large plastic bin that comes with it's own top so the trailer could be enclosed and waterproof. The wooden beam accross the top was because the sides of the plastic weren't strong enough to really hold their shape. conveniently I was able to put rope cleats tapped through the side of the box into this wooden beam so I also end up with a convenient point for tying things on top of the lid of the trailer as well as securing the lid.

Step 2: Chassis Underbelly

the dirty underbelly. this is a good detail shot of the chassis of the trailer. the chassis is made from 8020 extrusions of aluminum. this stuff is robust and re-useable, kind of adult lego, but it is expensive. you could similarly make the same chassis with pieces of timber, or even an old aluminum ladder might work well. nuts inside the extrusion are used to affix things. you can see the cross member plate is affixed in this manner, as are the axles at either side. The axles are 1/2in steel that fit to cheap wheels also bought from mcmaster. they were originally for a front loading tricycle I was building, but i got distracted...

Step 3: Detail of the Axle Wheel Attachment.

this is the hardest bit of a trailer. you need really strong axles if they are going to be cantilevered like this. hardened steel axles greater than 10mm in diameter are best. you can potentially use two old front wheels from bicycles, the difficulty with this option is making the axles work in such a way that you can fasten them either side of your bike. In Guyana i saw a lot that used two old front forks welded to the sides of a shopping cart, and similar such ideas. Anyway, in this one I used the half inch steel pipe through the centre of a half inch bearing 24inch wheel, and merely put shaft collars with locking allen key thingies either side of the hub. the axle was then convenient and easy to stick to the 8020.

Step 4: Chassis to Axle Attachment

here is the detail of the axle to the 8020 attachment. two drilled holes through the axle were simple enough to do a friction fit to the 8020. nice thing about the 8020 is that the extrusion has the slot in it which makes the axles aligned on both sides.

Step 5: Chassis to Bike Connection.

this is how i built the trailer handle. So that the trailer wouldn't sit at a funny angle I needed an s-bend type thingy to raise the height of where it would attach to the bike. I had some funny pieces of wooden hand-railing that i drilled, screwed together, and then bound with waxed string. later this was to prove the weak point. the actual attachment to the bicycle is a pair of old crutches, these can be found anywhere.

Step 6: Handle to Seatpost Connection.

one of the critical points of a bike trailer is a sufficiently flexible attachment to the bicycle. I have always found a bicycle inner tube lashing works well, but here is another technique. I had this old rubber tubing. It fits neatly over the crutches on both sides. there are drilled holes in the crutches so i can remove the tube from one side, wrap around seatpost, then put tube back over crutches. tightening and tying the line that passes through the rubber tube makes a very fast, and very flexible connection that works well accelerating or braking and coreners well with rotational freedom in all axes. the line takes the high tensile loads when starting the bike.

Step 7: Attaching to Seatpost

this is a good detail of how the trailer attaches at the seatpost.



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    55 Discussions


    3 years ago


    ima make a wood box though this would be great fr groceries


    9 years ago on Introduction

    This is a great idea.  Seems like I find old bike trailers at yard sales pretty often, but the hitch is always missing.  This could come in handy

    1 reply
    Yard Sale DaleJamieV

    Reply 6 years ago on Introduction

    You can buy replacement hitches and brackets on Amazon, easily for about $10 to $20. If you get the trailer for free because of a lost/old hitch system, you basically get a working trailer for the price of the hitch.


    Reply 8 years ago on Step 3

    I thought they were wheelchair wheels. They look like the wheels on a cheap wheelchair I have. I think I might have to use them for a bike trailer. :D


    Reply 8 years ago on Introduction

    Yea I was thinking of just turning the wheelchair into a bike trailer. Since the wheelchair folds, I could have a folding bike trailer.

    saulproffesor cuddles

    Reply 11 years ago on Introduction

    actually they are from the mcmaster carr catalog. i think they are for industrial trikes and big handcarts.


    Reply 8 years ago on Introduction

    Another source: This is a nice design concept. Looking at it, I'm wondering if smaller wheels might be better (lower center of gravity). Also, if the tote were of heavier plastic, like a fish tote (, you could poke a solid axle right through the box, just above the bottom, and attach the hitching hardware to the top edge, or near the top, and reduce the bends. Or a solid axle could be attached directly to the underside. Coastal people might find some fish totes abandoned by the roadside. I think electrical conduit would have made a better attachment. A 1/2-3/4" hand bender goew for about $30, a good investment for someone doing a lot of this kind of DIY work.

     This is a good idea!  Way to reuse items you already had lying around!  I know lots of people who just throw away old totes, but this is a great way to breathe new life into them.  Keep up the great work.

    To *bicycletrailersonline*:  I agree that your manufactured ones would probably hold up better than *saul's*, but that kinda defeats the purpose of this site.  I would love to be able to afford a manufactured trailer with some type of warranty, but with things as they are these days, I also had to look around and use what I had.  If a person was to go out and purchase all the items *saul* used, it probably would be very close in cost to your cargo trailers (I like the Quik-Pak, myself).  But, as he mentioned, he had these parts lying around.  No disrespect meant!  Swear!  I just notice that your comment seemed to be more of an ad.


    9 years ago on Step 3

    they are made by a company called skyways, and they make the chassis for bikes, wheel chairs, and pretty much anything that need a hard wearing, plastic wheels.


    10 years ago on Step 5

    Conduit - aluminum or EMT is easily bent - up to about one inch diameter. Some electrical shops will sell you a piece of scrap and bend it for you. Don't think I would go larger than two inch. 1-1/4 inch would probably be about right.