Utility Cycling - pulling and pushing from the trailer

I don't remember my old trailer doing this. My Burley trailer, which I've had a few months now, pulls and pushes, in an oscillating pattern, while I ride, worse as the cargo weight increases. What causes this, and how can I mitigate it?

have you checked the bearings? check that everything is nice and tight.

The trailer has no bearings except in the wheel hubs, and those are working right. I'll send pictures of the trailer, focusing mostly on the hitch. That is secure, too, I think.

Is there a spring in-line with the tow bar? That can do it. Easiest is to try and smooth out your pedal strokes, harder would be to try and stiffen the spring.

I have a Burley and I've felt this too. I think this is natural for all trailers. Perhaps their frames are a bit flexy, especially the tow arm and rubber linkage. Additionally, whatever cargo you are carrying has inertia. So any changes in your bike's velocity will have an effect on it, and that is usually felt as oscillations (i think).... Try to keep your cargo strapped down, but if your cargo is a kid, you want them to have some level of movement for comfort. Also, try to keep your speed constant, and accelerations and decelerations smooth.

I think I understand the physics but it's pretty severe. I pulled both my daughters, even up to the time they were 7 and 4 years old, and I mean I pulled them simultaneously, so that's a bigger load than a 60 pound dog. I just don't remember the oscillation being this severe. Maybe my memory is off. I pulled my daughters in an Equinox trailer. The construction looks similar. In fact, this Burley looks better than (my memory of) the Equinox, but I can't say for sure. I haven't had the Equinox since 2003, and I hadn't used it in a while when I stupidly gave it away.

Is there a spring in-line with the tow bar? That can do it. Easiest is to try and smooth out your pedal strokes, harder would be to try and stiffen the spring.

I have a cargo trailer that uses a spring in the hitch, and it does exactly what you are describing. It 'pulses' in response to road irregularities, as well as uneven pedal strokes.

My touring trailer has a seat mounted hitch, and has none of these tendencies.

Yes, this is caused by the play and flexibility of the Burley rubber hitch tongue. I mean, it's essentially caused by an uneven pedal stroke, but the flexible hitch exacerbates the effect.

The only way I've found to mitigate it is to be smoother on the pedals, and I'm interested to hear of other possible solutions, although I think the only thing to be done, really, is to replace the tongue with a material that has less horizontal flexibility while retaining the flex in the vertical axis.

I should add that I don't use a Burley trailer, but I do use their forged hitch, tongue and pin, and experience this myself. I wouldn't call it severe gyration, however, and perhaps if it is, it may be time for a tongue replacement. I imagine they fatigue and get more prone to stretching, but I don't know.

I can't even remember the brand of my trailer, and I loaned it out for the weekend. I now attach it more firmly, and that does make a difference. So it seems to be mostly in the hitch mechanism where I attach it to the bike. I might try wrapping the interface with some bungie cords, to see if that helps.

Thanks for your help. It really makes a difference. I know that this force can't be eliminated, but it's good to find that I can reduce it.