Introduction: Quick Hitch for Bike Trailer

Picture of Quick Hitch for Bike Trailer

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.

1 X Male 3/8 pneumatic connector
1 X Female 3/8 pneumatic connector
2 X 1/4 (or smaller) eye bolts

Step 1: Disassemble the Female Connector

Picture of 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.

Step 2: Eye Bolt Work

Picture of Eye Bolt Work

Lay one of the eye bolts next to the threaded portion of the Female connector to see how much needs to be cut off/ if any. You will want the thread end of the bolt to be recessed in the connector so that it does not get in the way later

My bolt was too long so i had to cut it down.

Next the peaks of the nut for the eye bolt were just to tall so i had to file them down. Now the nut will drop all the way inside the connector. Now give the bolt a good tightening and it should be snug.
Now reassemble the female connector.

Get the other eye bolt and place in the vise in such a way so that you can open the eye. Take care of the threads. Bend open the eye and insert the Female connector eye bolt assembly. Then use the vice to close the eye.

Instead of using the second eye bolt you could substitute it with a U-bolt depending on your application.

Step 3: Male Connector Application

Picture of Male Connector Application

Depending on what bike you have, your frame rail type and how old your bike is this next step is different.

My bike has a large enough hole in the frame rail that i was able to insert the male connector by cutting down a fitting and using a washer to fill out the hole.

my wife's bike did not have this hole so i had to cut down the male connector and use a metric bolt to thread into; where i assume the disc brake caliper or a fender support would be bolted on. I have not yet tested this for strength. But I would think i could stand on this connector and it would hold.

Refer to these other Intructables if my poor directions are to lame. Because these guys gave me inspiration


Gelfling6 (author)2011-04-03

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)Gelfling62011-04-03

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.

Agent803 (author)Sindrone2016-11-18


supuflounder (author)2015-08-10

Needle noose => needle nose

loosing => losing

vice => vise

joey.heider.1 (author)2015-05-19

I just used this hitch set up for hauling my kayak and it worked out great.

HappyToBeAlive (author)2014-09-14

awesome thinking outside the box...

druidrat (author)2013-02-17

simple and elegant, couldn't ask for more.
good job

spratjack70118 (author)2013-02-14

Hey Sindrone, I used your hitch Instructable for my Mini Teardrop Trailer Instructable. It worked quite well. Thank you.

AeroKB (author)2012-03-14

Well done!

RedShedProjects (author)2012-02-17

I had the exact same idea but ended up making one out of a nylon block; more complicated but original! :)

chadeau (author)2010-07-10

Must have a different type of connector-I pulled the spring,but the valve did not come out-more disassembly?

Sindrone (author)chadeau2010-07-10

yes; you must unscrew the two halves of the coupler. 4th, 5th, 6th pics of step one. I did not make this clear, sorry.

bikerusl (author)2010-06-25

A quick connect coupler can also be purchased for not too much money:

chadeau (author)2010-06-07

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)chadeau2010-06-07

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.

Chicken_Potpie (author)2010-05-25

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!

chadeau (author)2009-12-28

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 !

ericdncn67 (author)2009-07-19

that is slick business. thanks-eric.

Handsome-Ryan (author)2008-07-21

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:

Sindrone (author)2008-06-10

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.

smithy813 (author)2008-06-09

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...

handyguy (author)2008-05-17

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.

handyguy (author)2008-05-14

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.

dchall8 (author)2007-12-26

Would locking steel carabiner work to connect two eye bolts?

ranger_steve (author)dchall82008-05-11

yes u should be able to

dewexdewex (author)2008-05-08

The more I read the more I realise I should shut up!

dewexdewex (author)2008-05-08

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.

dewexdewex (author)2008-05-08

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.

Tobita (author)2008-03-20

the ingenuity of the instructibles never seem to stop amazing me! great instructible!

srilyk (author)2008-01-11

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)2007-12-27

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.

zer0vector (author)2007-12-27

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.

dacker (author)2007-12-26

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!

GorillazMiko (author)2007-12-26

Cool, plenty of pictures, great instructable.

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