rickpaulos

removed from a bike today. fitted to the rear axle, left side. The pad was on the underside of the chain stay. The round fitting is an air connection threaded into a nut that is welded to the bracket.

Appears to be commercially made. Looks inadequate to be an trailer hitch.

Reynolds 

Homemade trailer hitch IMO.

Doug64

It is a Bike Friday trailer hitch.

A friend gave me a Bike Friday trailer.


The trailer was great for hauling groceries.

Troul 

A shop pneumatic fitting welded to a piece of metal.

Camilo

Doug64 Can you show the actual Bike Friday hitch you have for comparison- how it hooks up to the trailer?

Duragrouch

I was going to say the same, BF hitch, or someone's improvised copy of it. The trailer side would simply be a female air coupler for that male one (and you need to be careful, some look similar but are different) attached to a piece of semi-flexible pneumatic hose (which is strong, has fiber reinforcement), that connects to the trailer arm. A very simple way of providing a flexible joint, and can be easily refreshed over time with just a short piece of standard hose.

Not certain, but I think BF originally welded that male coupler directly to the frame. Putting it on an axle bracket is smarter, easier to replace or repair if the weld breaks.

rickpaulos

Thanks, Doug64.

Now that I know what to search for I found this listing that shows the hitch.

"Also included an axle hitch and air nipple."
https://www.bikepartners.net/travel-...th-1-bike.html

Camilo

Not knowing much about it, but I do own an air compressor with quick release connections. I guess I'm a little surprised that this will be strong enough for whatever forces might be involved in a mishap. But then again, it's a reputable company, and I really doubt I could separate my compressor connections by any means at my disposal (hammer, pry bar, etc.).

I wonder could I disconnect it if I attached one end of my compressor hose to a post and the other to my car and tried to break the connection. Would the hose break first - and is that the weakest link in the trailer connection system.

Is there a weight limit? Would it be considered safe for a child wagon - say, if something caused a strong force to separate it from the bike?

Just curious. Seems like a simple and elegant connection solution.

Duragrouch

The connection is plenty strong, rated for probably at least 150 psi, and that is trying to blow it off the end of the hose. Sometimes you don't want a connection that is too strong, you want it to separate in a collision.

Camilo

That's kind of what I was wondering about the suitability to a child carrier. Obviously the one illustrated in this thread is for cargo, but I was wondering if it would be trustworthy enough for "precious cargo". Would it break away under certain forces, and would you want it to.

Not really germane to the discussion, just curiousity.

Duragrouch

I think most child trailer hookups are not any stronger. But with hills, I would not want it coming loose. Simple solution: Just like with vehicle trailers with safety chains, rig a backup out of thin plastic covered stainless steel cable with a clip, just snug enough so that if the standard hookup comes loose, the trailer hitch end stays attached but doesn't go into the rear spokes.

I should get paid for advice this good.

Camilo

I believe my friends kid trailer attachment has that kind of safety cable. Don't know the brand.

Duragrouch

I don't doubt it, it's a pretty obvious safety measure. I just recall my B.O.B. trailer (1990s) had no fail-safe, and I was too clueless at the time to rig one.

Camilo

When my kids were young, we had a Cannondale trailer, two seater, facing backwards. It was solidly connected directly to the seat post, like a trail-a-bike type thing. The kids loved it, but it was much more "basic" than what's available now.

Doug64

noimagination

I suppose that's cheaper (for Bike Friday) than paying an engineer to design a proprietary releasable trailer-bike connector.

(This is a relief - I couldn't figure out why one would want to connect a compressed air source to a trailer hitch.)

Doug64

The hitch works well. I've pulled a load of groceries weighing an estimated 55 lbs. up a hill without any problem. Well, the bike's engine huffed and puffed a little

LarrySellerz

That is so janky lol.

Duragrouch

Well, you could use a socket-wrench U-joint, but you'd have a hard time drilling or welding to it. More probably, it would be a Heim joint (aka spherical rod end) with threads attaching it to trailer tongue, and on the bike a bracket that would hold the rod end in double-shear horizontally, hole vertical, with a clevis pin through both, held with cotter pin or ring. In that orientation it would provide unlimited lateral swing for tight turns, and limited vertical misalignment, of the trailer tongue.

rickpaulos

I worked at a dealer and I had to assemble the early Cannondale trailers. Cannondale would put all the parts in a box. No factory assembled parts other than the metal parts riveted to the plastic hitch and the finished wheels. The punched out holes in the emt frame were often incomplete so we had to finish the punch or drill them out. Cannondale was fine with having the dealers do final assembly to save on shipping. The popular seat & handle bar bags and panniers where shipping with the liners not installed. This yellow one was about Version 3. The yellow is much more visible and doesn't act like a heat sink on warm sunny days. Those wheel covers were added to keep the kids fingers out of the moving spokes. More plastic, less frame work so they were much easier to assemble but they still had issues. The high mounted hitch has some effect on bike handling. I watched one parent roll the trailer when he took a corner too tight and one wheel rode up the curb and flipped the trailer and kids. They did have their seat belt on and were wearing helmets so no physical injuries that day. Another local club member pulled the kids for a century ride and those kids got severe sunburns. And there has to be some psychological effects of watch passing cars coming nearly straight at you. Oh and the toys and bottles tossed overboard. Really the newer trailers like the Burleys and the many clones are much better for taking the kids along. All the new trailers fold up so they fit in a smaller box for shipping to the stores or on-line buyers. Quick release wheels are standard on many. Easy enough stow one in a car trunk for a drive to a nearby trail. Once the nylon material is ruined by leaving them out all winter, they serve a second life for the homeless to transport their possessions. Without a doubt the most popular trailers are from Instep (makers of Schwinn trailers)j. They have a pretty simple hitch. A single piece of stamped sheet steel, a keyed washer and an off the shelf hardware pin. $10 part that won't fail.