Bicycle Trailer Ver 3.1

Stuart Ablett

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Tokyo Japan
On a cycling forum, a member posted this info when I rebuilt the tongue of the trailer, as it turns out he knew what he was talking about.....

bme107 said:
In addition to the reinforcing you have I think I would have added some plate horizontally at the neck where it crosses the top and bottom rail of the basket. Reinforce the neck from any twisting forces at this joint and spread the load out more across the admittedly smaller basket rails.

Your gussets in the neck probably will be plenty for this use but a note for future projects: Two smaller side gussets are better than one large center-line gusset when working with thin wall tubing. This is accepted good practice in bike frames as well as race car tubular chassis. Testing has shown that when the joint is bent the single plate gusset pierces the thin wall like a can opener and fails the joint. The side plates allow for more weldable area and the spreading of the force over a larger area.

He was right on the money with this info, as it was always in the back of my mind, and I checked fairly often for signs of cracks. The other day I found some cracks, which would have led to a catastrophic failure.

ver_3_1_crack.jpg

You can see the crack, it extends almost all the way around the tube, and started from the center gusset, yes it acted like a can opener.

I have now taken his suggestion to heart and have fixed the problem, quite possible it is overkill, but I need the trailer to be reliable and stop breaking!

When in doubt as Larry says.... :D

ver_3_1_welded.jpg

First I welded the crack up, I bent it open a bit and filed it down so I could get it to close all the way, as it was a bit stretched, then I cut out some super mondo gussets, that will cover the whole deal, both sides, from the strong back at the basket of the trailer right up to the parking brake at the hitch.

ver_3_1_full_gusset.jpg

I welded it all along the top edge and I drilled some holes so I could button hole weld along the bottom edge of the tube. I think this will be rather strong. :thumb:

ver_3_1_full_gusset_painted.jpg

Both sides done with some paint on it.

The finished trailer, Version 3.1
ver_3_1_full_gusset_tounge_1.jpg

ver_3_1_full_gusset_tounge_2.jpg


This added right around 2Kg to the trailer, bringing it right to 33Kg, but the new weight is on the tongue of the trailer making it feel somewhat heavy, but not a big deal. The first thing I noticed is that the trailer now feeds all the bumps and wiggles back to the bike, I guess the new gusseted tongue is much more rigid than the old one. I now know that the old one flexed a lot, which is what led to it's failure.

With all that I've learned from this trailer, I'd love to build an all new trailer, but that is not in the works for some time to come, maybe next spring, if I can swing it. For sure the next trailer will be built from bicycle CrMo tubing, and I'll get a pipe bending machine to eliminate more welded joints.

Cheers!
 
stout, indeed! Interesting bit of explanation, there, how that centered gusset acts like a can opener digging into the pipe. I wouldn't have thought of that, but it makes sense.

2kgs is not inconsequential, but how much cargo do you normally haul in that trailer? 2kgs probably is only a small fraction of that!

I've thought about getting a small cargo trailer also -- found this one online. Maybe next year, if the price of gas stays up like this!

Did you change the hitch where it hooks to the bike? I don't recall the double connection. The tail lights (macgyver'd flash lights?) on the trailer are new to me also. Do they blink?
 
My dad had a similar issue with a hay bale hauler he built and sold years ago. The guy returned it as it was bent and cracking at the gusset. The old farmer admitted that his grandsons had been lifting up a 1500 lb bale, but it was frozen to the ones around it and they had 3 of them off the ground before they notice it bending. :eek:

He ended up re-enforcing the square tubing with an smaller piece that slipped inside the outer one and welded them all up at the joints together.

I'd agree with Dave. you probably need to add an isolator to help with the ride and vibrations.

Nice work! :thumb:
 
stout, indeed! Interesting bit of explanation, there, how that centered gusset acts like a can opener digging into the pipe. I wouldn't have thought of that, but it makes sense.

2kgs is not inconsequential, but how much cargo do you normally haul in that trailer? 2kgs probably is only a small fraction of that!

I've thought about getting a small cargo trailer also -- found this one online. Maybe next year, if the price of gas stays up like this!

Did you change the hitch where it hooks to the bike? I don't recall the double connection. The tail lights (macgyver'd flash lights?) on the trailer are new to me also. Do they blink?

The whole trailer weighs in now at about 32Kg/70lbs, I often have loads over 100Kg/220lbs my heaviest including the trailer was 165 Kg 364 lbs including the trailer, I do not have a pic of that, but here is the second heaviest, at 153.8 Kg 339 lbs.
153point8_a.jpg

This is not your normal run of the mill trailer, or hauling job, I do this kind of stuff 5 days a week.

Yes the lights flash..........
http://www.youtube.com/watch?v=pbbcESRP6MI

.... they are lights that are used to mark road construction etc, they have two D size batteries in each, which is also heavy, but they last a long time!

I built a new trailer hitch the one I fabricated for the new bike put the hitch point too far back, it would push me sideways in corners, the new hitch is much smaller and compact, and on the seat tube so it brings the hitch pivot point forward a lot more, way better handling.

With a heavy load on starting from a stand still is hard work, even with gears, and some of the stop lights I always seem to hit are actually up hill slightly, so boy do the old legs get a work out! I did a total of 53 minutes of actual wheels in motion deliveries today, not my highest minute count but a bit above average.

Cheers!
 
Hey Stu,

The new version is looking good!

I just ordered the double kickstand you have for my bike based on your pictures and excellent review on Amazon. Thanks!
 
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