Instructables
Picture of Quick Hitch for bike trailer
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A quick connector for a bike trailer. So that the trailer can be switched between multiple bikes easily.
Not cumbersome and keeps the bike looking "normal". My wife and I live about two blocks from the grocery store and want to be able to use our bikes to get the goods. We have limited space were we store our bikes and the storage will not fit a trailer. I want my wife to be able to easily hook and unhook from the trailer while I am at work.

Using
1 X Male 3/8 pneumatic connector
1 X Female 3/8 pneumatic connector
2 X 1/4 (or smaller) eye bolts
 
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Step 1: Disassemble the Female connector

First you will need to disassemble the female pneumatic connector.
Using needle noose pliers reach into the threaded side of the connector and grab the spring and give a pull. The spring and another small piece will come out. You may discard them they will no longer be needed.

Before continuing note the action of the small ball bearings and the slide section of the Female connector.

Using some pliers and a wrench loosen/ split the connector. Do not attempt to work the slide while the connector is apart. Other wise you run the risk loosing the ball bearings. Set the slide section to the side until you are finished with fitting the eye bolt.
druidrat1 year ago
simple and elegant, couldn't ask for more.
good job
Hey Sindrone, I used your hitch Instructable for my Mini Teardrop Trailer Instructable. It worked quite well. Thank you.
AeroKB2 years ago
Well done!
I had the exact same idea but ended up making one out of a nylon block; more complicated but original! :)
Gelfling63 years ago
You could probably skip the entire dis-assembly of the connector, by using a pipe nipple to a end-cap, threading the eye-bolt through the end cap, Likewise on the male end, using a end-cap on a male thread, or same nipple to end cap on a female thread. The question though, is mounting it to the frame of the bike... There was another recent discussion, about a low to the ground trailer idea.. the back frame for the bike, might work as the tow hitch..
Sindrone (author)  Gelfling63 years ago
That is the great thing about instructables. One can interpret or modify the plans in any way you see fit. This seemed to work best for me in my situation.
chadeau4 years ago
Must have a different type of connector-I pulled the spring,but the valve did not come out-more disassembly?
Sindrone (author)  chadeau4 years ago
yes; you must unscrew the two halves of the coupler. 4th, 5th, 6th pics of step one. I did not make this clear, sorry.
bikerusl4 years ago
A quick connect coupler can also be purchased for not too much money: http://www.midwestcontrol.com/catdisplay_short.php?pg=119
chadeau4 years ago
If a person added another nut closer to the eyelet,(3rd to last photo) one could bend the loop w/o damage to threads...
Sindrone (author)  chadeau4 years ago
True; it would help to add a second nut. The threads were not damaged in my application, but that is not to say someone else would not have said problem.
Wow! Thank you for this. It brought back memories from long ago. This design was in popular mechanics in the late 70s or early 80s with plans for a trailer built from pvc pipe. I built one (including this coupler) and it was AWESOME! I towed mine until it was about worn out. This coupler is a great design and can be very cheap depending on where you get the air fittings from.

Thanks again for the memories!
chadeau4 years ago
I bored a pair of holes in my aluminum-framed Schwinn when I found I received the wrong B.O.B. Nutz from my local shop-but only advise this if there is sufficient thickness in rear stays and double-check for cassette/chain clearance !
ericdncn675 years ago
that is slick business. thanks-eric.
After seeing this I made a hitch to pull my stereo trailer using an airline coupler. I also used a castor wheel bracket to allow for up and down and side to side movement. The rest of the thing is welded and attached with hose clamps and old innertube to protect the frame. My camera was almost dead so the pics are hard to make out but I'll link to them anyway:
Hitch1.jpgHitch2.jpg
Sindrone (author) 6 years ago
Yes you could use a "s" Hook. You may get a lot of undesirable lurch or rattle even more than with the two eye bolts. One thing i have found is; if a person has an old 10 speed "skinny tire" tube they can cut a small section and place it around the eye bolts. In essence a sock over the joint. To less the lurch and rattle. One could also us black electrical tape or something of that nature.
smithy8136 years ago
what about adding an "s" hook (closed up) between the eye bolt and a "u" bolt to give some more freedom? I'll try it and let you know, unless...
handyguy6 years ago
I fixed the rattle and lurch some by stuffing a large O-ring into the empty space in the split link. I folded it in three and in used all the extra play up.
handyguy6 years ago
I used 1 link of a small chain bolted to the trailer tongue. A split screw link attaches the chain to my derailleur protector loop - the bent metal link bolted to the axle on my mountain bike. It does rattle when unladen and lurch at times when full, but cost next to nothing. Whne doing this you must check back axle nut ocassionally for tightness, as the vibration tends to work it loose.
dchall86 years ago
Would locking steel carabiner work to connect two eye bolts?
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stevie1 dchall86 years ago
yes u should be able to
dewexdewex6 years ago
The more I read the more I realise I should shut up!
dewexdewex6 years ago
aha! an airhose connector: I just read a little more closely: that is a bloody good idea. Why not use some stiff fuel hose for the flexible part instead of eye bolts? Then it won't clatter about when you're not using the trailer.
dewexdewex6 years ago
Ecxellent idea! I'd be tempted to slip some rubber tube over the eyes so the gap is closed up. This will prevent lurch and clatter when you;re pedalling. I did something similar to yours a while ago, but nowhere near as elegant.
Tobita6 years ago
the ingenuity of the instructibles never seem to stop amazing me! great instructible!
srilyk6 years ago
I don't think you should have a problem with the side load unless you have a really unbalanced load. I think some time I may try to stress test the Harbor Freight variety of "industrial" (steel instead of brass) couplers. I imagine the tow strength should be quite high, and I would assume the side stress would be nearly as high. Certainly more weight than one could conveniently haul with one's cycle. Great 'structable!
Sindrone (author) 6 years ago
dchall8: yes you could use a carabiner to connect the two eye bolts but there would be way too much X,Y and Z axis slack and i think would cause more problems than just using a u-blots instead of the second eye-bolt. zer0vector: The side loading of the coupler i do not think will be an issue. I have used these on air hoses for many years and have yet to have a connection come a part due to stress. If you go to a hardware store and they have these to connectors(male and female). You could test these by connecting them and try to pull them apart/away from one another. I think you will find they are very stout.
zer0vector6 years ago
My only worry is that the way you have it set up, you're side-loading the pneumatic quick release. I've never worked with one, so I'm not sure if it would be a problem, but hopefully it won't weaken or damage the connector.
dacker6 years ago
Ingenious I never would have thought to use an air coupler as a quick-connect anywhere else! I'm going to have to add that to my bag-o-tricks!
Cool, plenty of pictures, great instructable.