StuInTokyo
Maximum Pace
- Dec 3, 2010
- 1,662
- 62
- Thread starter
- #21
Have you not thought of an attachement that conects at the bottom of the rear stays and uses the Quick release to lock in to place?
The load doesn't have to be shared over multiple joints or angles and if it does fail then it doesn't require huge amounts of engineering.
Also all of the forces are in one direction rather than multiple. Other ideas could be based around the hitch clamping to the bottom of the stays thus spreading the load over a wider area.
I have looked at the lower mounting point, but from my research online, a higher mounting point, with a low slung trailer (center of gravity below the axle) is the most stable set up for hauling heavy cargo.
To quote from Tony's trailers......
See the two pix that I have marked with what I call "the line of stable equilibrium". Sound slightly nautical and if you have ever wondered what kept your boat from overturning you may have run across a similar term at least with that word mentioned
Low hitch, less stability.
High hitch, more stability.
This line runs from the pivot on the hitch to where the rubber hits the ground-which is the point at which the forces act that are trying to tip your trailer over (This applies to trailers no matter how many wheels they have and this is contrary to popular belief that these forces act at the height of the hub of the wheel).
All weight below this line tends to keep the trailer upright with no twisting moment on the hitch. Thus the higher the hitch and as low as the trailer can go and still have adequate ground clearance the better.
The two pix clearly show the larger volume available to the trailer with the seat-post hitch. It works out to about five times greater than the axle hitch can provide.
All of this translates into more stability when loaded, especially as we now know where to put all the heavy stuff. So it looks like the load is 500% more stable by using the seat-post hitch.
The other advantage of the seat-post hitch is the potential for carrying heavier loads because with all single wheelers the bicycle gets to share half of the weight of the cargo. And the high hitch loads the bike forward of the back wheel axle-see intro to cargo trailers which of course is far superior to dangling it off the back axle or worse- behind the back axle-or worse again behind the back wheel
Ground clearance was mentioned and it seems that in practice 4 inches is adequate even for most off-road stuff.
You will notice that to get this clearance on most single wheelers that hitch onto the rear axle you have to run 12.5" or 16" wheels. Talk about sluggish!
With the SST you can have any size wheel you want, still have the low ground clearance and thus maintain the higher stability factor. And enjoy low-low rolling resistance especially off-road!
While the pics and the text talk about his single wheel trailer, it also applies to a two wheeled trailer, and the larger wheel size he talks about is also important.
I thing with the very skookum rack I'm building which will also be able to function as a rack and carry the two panniers, I will cover all the bases. I will have to modify the trailer again, I think this will become ver 2.5
Please keep the suggestions, and observations coming, I'm not rejecting anything out of hand, all of your comments make me think, and evaluate what I'm doing, for that I'm grateful, thanks!