Engineering Question

I'm in the single wheel trailer planning/collecting parts phase. I want to build the style in the link below. In this pic you can see that where it swivels side to side it is leaned forward. I have also noticed that on bicycle trailers and others this pivot point is leaned forward.

This type trailer hooks to the bike with a long bolt through the rear axle and that is where the up and down movement comes from.

So for you engineering types. Why the tilt forward at the pivot? I thinking maybe for extra "tongue" to road clearance in corners but not really sure.

Thanks


http://www.moto-mule.com/152.jpg

I have no idea why they did that. You can see the one I built in my gallery and mine does not have that and works great.

Counter swivel. If it were straight any weight in trailer off center would make it ride off of center line of bike. This " makes alignment to bike a little more ridged"

I think they just did it for proper alignment... level. Counter swivel....yeah, maybe.

Counter Swivel? Kinda like caster or rake adds stability?

Skunkape said:

Kinda like caster or rake adds stability?

Click to expand...

IMHO yes, especially when I imagine this assembly leaned over in a bend/turn...

It doesn't make sense to angle the swivel like that. In that swivel's current form, when the motorcycle suspension compresses, the trailer is provided forces thru that swivel which try to push the trailer out to the side. I bet that trailer doesn't trail straight except when there's no suspension movement.

To add some commentary.... Most trailer hitches are suspended from the bikes frame (under the seat), not from the swingarm.

This trailer hitch shows to be hard-mounted at the rear wheel axle and must rotate with the swingarm--when the suspension is compressed, the swingarm changes angle, and the trailer will be lifted (or will drop sideways). If someone sits on the seat and suspension is compressed, the trailer is lifted, so the trailer's suspension has to extend (or the trailer is lifted off the ground).

Very strange. Makes for a nice picture though.

It is also possible that there's an additional hitch pivot point around the rear axle, allowing the trailer not to be lifted by compressing the bike's suspension.

BakerBoy said:

This trailer hitch shows to be hard-mounted at the rear wheel axle and must rotate with the swingarm--when the suspension is compressed, the swingarm changes angle, and the trailer will be lifted (or will drop sideways). If someone sits on the seat and suspension is compressed, the trailer is lifted, so the trailer's suspension has to extend (or the trailer is lifted off the ground).

Click to expand...

On many bikes including mine the rear axle is hollow. The trailer is mounted with a bolt/pin all the way through. The trailer is then free to rotate up and down there. The front of the trailer goes up and down with the bike's rear tire. Basically no suspension at the front of the trailer. However I think I have that worked out.

Check out this video it shows a lot more. About the 2:00 mark.

[video=youtube;dmBQHLxsC7M]https://www.youtube.com/watch?v=dmBQHLxsC7M[/video]

I am sceered of that design. For the reasons BB stated, the trailer would be taking a server beating when you hit any bumps at speed. And who does that? ;>)
I would look to drop a goose neck of sorts, from the frame, under the seat.

I believe, the angle on the downtube spreads the forces through the bearings better than straight up and down.

The forward tilt creates negative feedback that reduces side to side oscillation when riding straight. The weight of the beer cooler will push the rear wheel to track behind the motorcycle. Just be real careful when ya get to camp cause yer beer will give ya a bath....