Instructables
Picture of No Weld Bicycle Trailer Hitch
This is a complementary instructable to the No Weld Bike Trailer. This instructable will show you a quick air hose coupling based trailer hitch, that connects to that trailer.


 
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Step 1: Supplies

Picture of Supplies

The supply list for this hitch is well under 5 bucks, here is what i used:
1 Male Airhose coupling
1 1/4" bolt
1 1/4" nut
1 U bolt (1 and 1/4")

Drill
Drill bits necessary to complete the job.

Step 2: Drill the Ubolt Plate

Picture of Drill the Ubolt Plate
Most Ubolts will come with a metal plate, Drill into this with a standard drill bit about 1/4"

Step 3: Put the Bolt and Nut On

Picture of Put the Bolt and Nut On

Put the nut on the bolt and the put the bolt through the metal plate like the picture below.

Step 4: Thread The Airhose Coupling On

Picture of Thread The Airhose Coupling On

Thread the airhose coupling onto the bolt, Use 2 wrenches to tighten everything down sufficiently.

Step 5: Put it on the Ubolt

Picture of Put it on the Ubolt

Put the bolt onto the ubolt like so:

Step 6: Attach to the seatpost

Picture of Attach to the seatpost

Lastly attach the hardware to your seat post and ride! If you don't want to scratch your bike seat post, wrap it in an inner tube. Use a crescent wrench to tighten it down. 
seaplanecfi4 years ago
That's a really ingenious coupling method, I like it! HOWEVER, a similar seatpost hitch that we've been using on a cart at local glider field wants to tip the bike over whenever we're stopped, because the hitch attach point is too high. Have you encountered that?
Are you certain it is not the center of gravity of the trailer that is trying to tilt the bike? Also, is the front of the trailer a bit heavier than the rear of the trailer? It needs to be.
For bikes with a steel seat stem simply buying a plumbing T and slipping it over the seat post might be a good start for a hitch. That should allow easy left right movement for a trailer and the other end of the tube could take care of the up and down movement. With a perfect sized T you could use the air hose connector easily. Or drill a hole through the middle nipple on the T such that a cotter pin can secure the tongue to the fitting.
Common to 'tall' hitches-also have the same situ with my BOB Yak trailer (single wheel)...best set-up is drop-out mount because it's lower on bike,tho wheel interference becomes an issue on tight turns...
chamunks3 years ago
Inspired and built. Though I swapped the main bar from steel conduit to aluminum pipe to lighten the load, and added some cotter pins in a few places to make everything quick release.

My U-Bolt didnt end up being too similar to yours and a slight mod or two to the actual coupling on my rig but all in all very good ible and this coupler works great I've hauled way more than I should have on this badboy for way longer than I should have.

I'm thinking though that whenever my sugru comes in the mail I will be padding the ring a bit so that my gunmetal black seat pole doesn't get too wrecked. I'll post some pics this spring when I can take them without freezing my fingers off if you're interested.
This might prove to be a stronger design along your same principles. Also there is less chance of the trailer separating. I just threw this together with Google Sketchup and parts from the 3D Warehouse.


bike hitch.png
frenzy (author)  mr.incredible4 years ago
This is awesome but the hose bit needs to stick straight out to actually attach to the trailer.
This would probably negate the whole "No Weld" theme you got here. I was also thinking the coupling on the tongue should be vertical.
bike hitch toung.png
thinking more about this...

I think uneven ground or hills might break or stress this one too much...
Goose Neck Trailor hitch just like on PU Trucks with a 5th wheel.
I like this design mo bettah.
Would it be possible to get a 90 degree elbow for an air hose so that you could have the upright pin?
On the curve of the u-shape that goes around the seat post one could take a hacksaw and put small cuts on the bolt to keep it from walking side to side maybe?
Mike Z4 years ago
Call me stupid -- (Your stupid!!!) But please show me how this attaches a trailer to the bike.
Big Bear4 years ago
The u-bolt plate looks thin and weak . You may get a more secure hold on the seat post with a thicker stronger plate. This is a nice idea though with some good thought.
l8nite4 years ago
very cool idea. nice ible although you could have shown the female part as well. Cutting off the excess threads would make it easier to manipulate the fittings, at least for those of use with larger hands
frenzy (author)  l8nite4 years ago
The female end is on the original trailer hitch instructable
l8nite frenzy4 years ago
I know the female is shown on the other ible, all I was suggestioning was that showing it here would help tie your ibles together and show the finished piece
omnibot4 years ago
Excellent, this really solves this problem in a most handy fashion.