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.....
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.
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....
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.
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.
Both sides done with some paint on it.
The finished trailer, Version 3.1
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!
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.
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....
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.
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.
Both sides done with some paint on it.
The finished trailer, Version 3.1
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!