trailer fixing help, probaly from flecc

[electric.mike]

flecc
a bit of advice please in you capacity as towing expert!! been out today to fetch a bag of coal, 25kg a 9mile round trip, the powabyke had no problem and the trailer worked,but although the trailer is sold as capable of carrying 40kg, i don't think it would stand this sort of treatment for long due to the state of the roads, the wheels and the hitch are not suitable.
to this end i intend to build one from scratch just for carrying coal and potatoes, i have done a fair bit of car restoration in my time so ime confident of my ability with the build,its the connection to bike i would like your advice on, in this picture you will see circled the only two points i think i can fix to using slightly longer bolts, the fixing would be on both sides of the bike similar to your system, but being an alloy frame do you think the frame would be strong enough to take it at this point, or have you any other ideas.
many thanks mike

 

[flecc]

That's basically where much of the strain is taken on my two Mike, but I've deliberately shared the load across the top carrier mounting as well, since I have some doubts about how much those two alone can stand, and they alone wouldn't stand downthrust.

On the Quando hitch:

you'll see that by mounting it a bit higher up the carrier rails, the top carrier mounting point also takes some of the load and allows nose weight to be taken. The same is true on the first hitch on the Twist that I set up nearly four years ago, as you'll see here:

Here the plates which are normally part covered by panniers spread the load diagonally up as well in the same way. I wonder if you could continue the attachment strip or bar up the rising frame tube a little way and add a strong clip around the tube as well.

If the two bolts you've shown are the only attachment points, the trailer nose weight bouncing on the road would I'm sure cause a failure.

An alternative would be to lead the strip or bar further along above the dropouts and clip it to the horizontal tube ahead of the dropouts. Then that would take the nose weight ok. Basically you need either to triangulate the attachment, or hitch it at two well separated points horizontally, either way taking the downthrust and bounce at the hitch end.

You'll see that both my attachments have some degree of flexibility, and this helps them last by absorbing shocks instead of the shocks breaking something too rigid.

What type of hitch do you have at present by the way?
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[flecc]

P.S. to the above.

In the absence of a carrier, something like this maybe, which would take nose weight and have just a small degree of flexibility:

Obviously would have to be either tube or be deeper section if flat strip, but this is just to illustrate the principle.
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[electric.mike]

flecc please have a look at this image, is this the two points you mean, ignoring the two original points, and perhaps taking a support up to the carrier on each side as well.
at the moment ime using the side clamp system with a spring to allow for movement, if can create a good solid mount i would change my current trailer to it as well.
mike.
ps
i was doing this at the same time as you but i see you have included the two bolts for mounting

 

[flecc]

What I mean is the two original points that you've circled in red Mike, with the mount carrying well forward to above the left hand yellow patch where there can be a frame clip for a third point of attachment as shown in my added pic. This third point would resist rotation due to nose weight and bounce on the two first points which could shear otherwise. Then the two original points just carry the downthrust which is into the frame so it's quite strong enough. I've added the three bolt points as black dots on the red bracket representation to make it clear. The extension of the attachment could be up the slope of the rising frame tube and clip there instead of course, if that is more convenient.

I guessed you were going to say a spring attachment at present, they really are hopeless for trailer control, just snatching back and forth all the time.

Up to the carrier is only any good if the carrier supports are very strong, but if they're only wire, it probably won't help much.
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[electric.mike]

thanks for that flecc it makes a lot of sense, just have to get a co2 refill and me and my mig can start playing.
mike

 

[flecc]

Mig. Your really serious! No sellotape for you then.
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