Trailer hitch prototype

[HandsomeRyan]

I welded up a new trailer hitch for my bike last night. It isn't perfect but it'll do until I make something better. Please ignore my crappy welds, this is a prototype and the final version will have better welds. A 3rd hose clamp would make it safer, as would a 4th support brace. The final version will also include a place to clip a safety cable.

http://i64.photobucket.com/albums/h170/HandsomeRyan/hitch1.jpg

http://i64.photobucket.com/albums/h170/HandsomeRyan/hitch2.jpg

http://i64.photobucket.com/albums/h170/HandsomeRyan/hitch3.jpg

I guess it isn't too hard to tell what you are looking at but please ask if you have questions. The tube is packed with grease to prevent rust and allow free movement. A key clip (pictured below) is the intended mate to this hitch.

http://www.keyosk.co.uk/images-products/pr-lead-clip-thumb.jpg http://www.keyosk.co.uk/images-products/pr-small-swivel-hook2-thumb.jpg

[bac]

Wow - how creative! I love it!

... Brad

[Nightshade]

The hitch on the bike is well designed and will hold up fine.
However, the "snaps" that are mated to hook up the trailer
are not designed to take the torsion,twist or load that a trailer
will impose on them and may fail rather suddenly.

I recommend a change to a matching eye bolt pinned with
a lynch pin & hair pin to get matching twist strength.

[JunkyardWarrior]

"I recommend a change to a matching eye bolt pinned with
a lynch pin & hair pin to get matching twist strength. "

that wouldnt let it move side to side.........open another eyebolt and hook the 2 together then close it.....instead of clipping the trailer on youd have to bolt it on, but it would be more theft proof that way

[HandsomeRyan]

The hitch on the bike is well designed and will hold up fine.
However, the "snaps" that are mated to hook up the trailer
are not designed to take the torsion,twist or load that a trailer
will impose on them and may fail rather suddenly.

I recommend a change to a matching eye bolt pinned with
a lynch pin & hair pin to get matching twist strength.

Not a bad idea.

There is a hitch design on Instructables.com that uses a small ball bearing castor wheel (minus the actual wheel) with a lynch pin. If I can find a suitable castor wheel for cheap (harbor freight maybe) I think i could weld a better mount than what is used in the instructable and have the ultimate in home trailer hitches.

See what i mean @ http://www.instructables.com/id/DIY-bicycle-trailer/

ignore the "trailer" part of the link above- pvc is NOT a suitable trailer arm material, but the hitch idea is very nice. Because i have access to welding equipment, I feel this idea could be made better with a welded attachment rather than the screws he uses in the instructable.

[Cyclaholic]

I like your work, Ryan.

Does the eye bolt rotate on its thread to allow for the lean of the bike?

[Juggler2]

The hitch on the bike is well designed and will hold up fine.
However, the "snaps" that are mated to hook up the trailer
are not designed to take the torsion,twist or load that a trailer
will impose on them and may fail rather suddenly.

I recommend a change to a matching eye bolt pinned with
a lynch pin & hair pin to get matching twist strength.

As regarding the "snaps", I see these used on dog leashes, some with sizable dogs. I don't know for sure how much torsion, twist or load they are rated for, I've never seen that data. YMMV.

[waldowales]

Here is another way:
http://www.flickr.com/photos/oldbikeguy/2063991383/in/set-72157603294105496/

[HandsomeRyan]

Does the eye bolt rotate on its thread to allow for the lean of the bike?

Yes, the eye bolt rotates freely to allow for leaning of the bike and/or trailer.

[mikepoole]

Hey Ryan

you might want to go to the West Marine store (apparently there is one in Knoxville) and have a look at their sailing rigging- they should have snap shackles and swivel snaps that have actual load ratings, along with some other bits that might be handy...

[Nightshade]

Hey Ryan

you might want to go to the West Marine store (apparently there is one in Knoxville) and have a look at their sailing rigging- they should have snap shackles and swivel snaps that have actual load ratings, along with some other bits that might be handy...

The main problem with snaps is what's called "whipping shock load" that happens during
the bumps and jerks of any road surface. This type of loading can add tons of force
right at the weakest point of a snap......the swivel. I've had the "head" pop off more than
one snap holding down a tarp from a sudden wind gust load.

It's like falling. The fall never hurts you, but that sudden stop (or jerk) is a b!tch. :eek::eek:

[mikepoole]

...I've had the "head" pop off more than
one snap holding down a tarp from a sudden wind gust load....

That's why sailing gear might be just the ticket...:)

[HandsomeRyan]

The ones i got from the hardware store are rated. one is 45# and the other is 65# I believe. those are of course very conservative estimates of the actual hook strength.

[mikepoole]

The ones i got from the hardware store are rated. one is 45# and the other is 65# I believe. those are of course very conservative estimates of the actual hook strength.

Was thinking more like

http://www.westmarine.com/webapp/wcs/stores/servlet/producte/10001/-1/10001/4161/377%20710/0/snap%20swivel/Primary%20Search/mode%20matchallpartial/0/0?N=377%20710&Ne=0&Ntt=snap%20swivel&Ntk=Primary%20Search&Ntx=mode%20matchallpartial&Nao=0&Ns=0&keyword=snap%20swivel&isLTokenURL=true&storeNum=2&subdeptNum=323&classNum=326
http://www.westmarine.com/webapp/wcs/stores/servlet/producte/10001/-1/10001/4113/377%20710%201796/0/Snap%20Shackles/Primary%20Search/mode%20matchallpartial/0/0?N=377%20710%201796&Ne=0&Ntt=Snap%20Shackles&Ntx=mode%20matchallpartial&page=CategoryDisplayLevel1&isLTokenURL=true&storeNum=2&subdeptNum=323&classNum=324

Snap shackles >1200# safe working load
Double shackle swivel appx 700#SWL, >1500#side breaking load

Overkill, of course. Especially if you didn't weld the eyebolt shut. :)

[HandsomeRyan]

wowie-wow-wow...

those are some hardcore clips.

i think i may scrap this design and do something with the castor-wheel design linked above. I'll leave it to some other individual to perfect this design.

[gerv]

Has anyone seen this?

http://www.youtube.com/watch?v=UaQJIdpVRYc

Interesting design.

[larry_llama]

My first trailer design was based around a hitch that I used a bearing castor for. While it did hold up for the time I used it, I would not recommend it for heavy loads or long term use. I actually used two castors, removed both of the rubber wheels and joined them together where the wheels would have been. This gave me a full rotation universal joint.

It seems to me the castor is designed to take loads parallel to the plane on which the bearings run. Think of its normal operation on the bottom of a chair or cabinet. Side-loading it is asking for trouble.

For now, I am trying to come up with a solution that incorporates old bike tire material - the flexibility and strength of steel beaded tire might work - I'm just struggling with how to lay it all out...

[HandsomeRyan]

http://i64.photobucket.com/albums/h170/HandsomeRyan/IMG_0384.jpg
http://i64.photobucket.com/albums/h170/HandsomeRyan/IMG_0386.jpg

Sorry the pictures are sketchy, my camera died as I was taking them and I haven't gotten new batteries yet.

I used this hitch to complete a 20 mile ride pulling the 50lb stereo trailer and it worked fine. I welded some 3/4"x1/8" steel bar stock to the mounting plate of the castor wheel. After re-greasing the bearings since my welding burned off all the existing grease, I mounted it with some hose clamps. I wrapped my frame with old innertube to protect the paint.

For the other end of the hitch I shoved a steel air-line quick connect into a 4" piece of 1/2" conduit. I drilled some holes through the conduit and airline fitting and welded them back for added strength.

This works great if you have a welder. I do not believe there is any way to recreate what I made without welding though.

[Floyd]

Good thinking and good job on the quick connect. Not sure how much 'pull' they can take but in the horizontal position would only be the pull of the weight of trailer and once you are moving not that much. I like it.