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FORUM GODFATHER.....R.I.P. PAT
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I'm not an engineer but I can tell you one thing, the attachment to the bike is way too high. It should be about axle level.
 

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Discussion Starter #4
Those are great although having a hitch unsprung like the one going through the axle is a terrible idea.

Now have a look at this. It wasn't my idea, I'm just to cheap to buy the tested one.
 

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Are those shocks loaded enough, and are they damping at all?

Static sag should be about 1/4-1/3 travel, or you're gonna have a bad time since the tire is only going to spend a small portion of the time on the ground.

Also, the rear section (the ladder-like bits) need some bracing to the, um... downtube(?) or it's just going to pivot around the swingarm.
 

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Discussion Starter #7
Now we're getting somewhere. The tire is not leaving the ground, the shocks are pretty supple and adjustable via multiple holes for the upper mount. Would you expand on the pivot action that is mentioned? That is what's going on and I can't place where it's coming from. The section above the tire starts swaying and then the tail starts to whip violently as this swaying accelerates.
 

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The reason everyone is right that says the attachment point for the trailer is to high is because the left and right movement is twice as more then if it was attached at the rear tire axel height. The movement is steering the trailer wheel causing it to sway. The sway is causing the bike to lean left and right. The trailer is counter weighting the bike so it will still track staight. The trailer will never be controllable mounted that high.
 

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I'm and ME as well. I agree with the connection point to the bike being too high. Another consideration is if the entire structure is square. With a high hitch point, any out-of-square welds or a slightly out-of-true axel will amplify lateral stability issues.
 

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Discussion Starter #10
I am a mechanical engineer and GW is spot on. Lower your pull point. Good luck!
If this is the problem then Eaglemate is selling a product that does not function as described...not only that but dangerous. I have not read any reports of this though. I understand the trepidations around a high hitch point, mainly the torque values on the upper portion of the bike either pulling you over, making it difficult to upright, or pulling the bike sideways in a turn. I do not see any of these causing the trailer to sway though.

If when you say the hitch point is to high you are basing this off of some reverse rake/trail or something related to the length and angle of the trailer, I would be open to hearing that explanation.
 

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I have had enough mechanical engineering to make me somewhat dangerous (I am a civil engineer). I also can not open your pics at work.

But from trailor experience hitch hieght is not as important as having sufficient tongue weight on the trailor hitch point. Loaded or unloaded you want 10% or a little more of trailor weight on the hitch point.

I have a utility trailor I need to add forward weight on to haul my bike with. The trailor has NO shocks and 1/2 ton leaf springs. It pulls fine but does jump off the ground on big bumps when empty.

Pardon me if your pics show something I have assumed incorrectly.
 

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Is your attachment point a universal joint or just a pivot on the vertical axis? That Eaglemate looks like it pivots on both the vertical and horizontal axises. If yours doesn't pivot both ways, you've created a about a 12 foot wheelbase. So I would imagine that would throw that 3rd wheel all over the place since the front two wheels will likely take a different track than the back two.

I was a "sort of" engineer in college. But then I went to law school and all that science stuff got replaced with BS. But even the lawyer in me thinks the hitch is too high :mrgreen:.
 

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It's tough to tell from looking at the photos.

I will throw in my theory though.

I believe that part of your problem is geometry related.

Looking @ photo 4, your receiver tube is not straight relative to the bike.


With a ball hitch (can rotate about three axes), no big deal, right?
With your U-joint hitch (two axes) -- when the bike is upright is trying to tip the trailer to the left. When the trailer is tipped to the left it is trying to drive in an arc--but the bike is restraining it, so it pushes the bike, the bike pushes back -- the tail wags the dog...

Another potential geometry issue is the angle of the u-joint when viewed from the side.
This one may not be as significant as I think the first issue might be--but here goes.

The vertical portion of the U-joint is tipped toward the rear.

When the trailer tries to pivot about the axis of the u-joint the change in vertical movement has to occur in the horizontal axis of the u-joint.
 

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Another potential is 'slop'.

The needle bearings in the u-joint are allowing movement between the two yokes.
I have read of others using a similar u-joint setup -- from one of the trailer manufacturers (I think) -- but they pull all of the needle bearings out of the u-joint caps and replace them with a tight fitting bushing/hard bearing.

If you have slop between the receiver and the hitch, that could, potentially, exacerbate the wig-wag of your new tail.
 

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Another potential is 'slop'.

The needle bearings in the u-joint are allowing movement between the two yokes.
I have read of others using a similar u-joint setup -- from one of the trailer manufacturers (I think) -- but they pull all of the needle bearings out of the u-joint caps and replace them with a tight fitting bushing/hard bearing.

If you have slop between the receiver and the hitch, that could, potentially, exacerbate the wig-wag of your new tail.
I looked at the photo gallery of the "Eagle Mate" trailer and I think you are correct. Their hitch seems to be horizontal from left to right to make sure the trailer is mated to the bike. The long rake of the trailer assures the majority of the weight is on the rear tire. I don't think any hitch type at such a high mount that allows movement side to side would work. The rear trailer would have be a solid extension of the bike allowing only up and down movement.

I would never of thought of such a hitch to make that work. Kudos to Eagle Mate
 

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bad design

dumbest looking thing I have ever seen, its hard enough for a car to tow a 2 wheeled trailer sometimes, let alone that rig and its attachment system
 

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I'm surprised nobody has asked the obvious question: "What the hell you fixin' to haul with that there contraption?" :confused:
 

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Had a look at your pics and havta say that you are very game towing that thing, the welding looks like absolute crap and wouldnt be surprised if the thing had no structural integrity at all which would show with the thing shaking itself to pieces. Is the wheel tracking directly behind the bike and inline with bikes wheels? I also notice you are using a universal joint for your pivot whereas every other trailer I have seen hs the up-down pivot away from the left-right one, that may be a contributing factor as well, also that other trailer you have based yours on show all examples mounted on a cruiser type bike which has a much lower tow point, every other trailer I have seen has a lower tow point.
Cheers Brian
 

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Those are great although having a hitch unsprung like the one going through the axle is a terrible idea.
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I agree , the first time i saw a pic of the mule , i didn't think much of the hitch system :thumbdown: i then read some reviews and watched a couple of videos i found , it seems to work ok on and offroad but it just goes against the grain to bolt a hitch to the rear axle :confused:
Ozzy Strom
 

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Discussion Starter #20 (Edited)
the welding looks like absolute crap and wouldnt be surprised if the thing had no structural integrity at all
Why don't you tell me what you really think.


I appreciate all of the constructive advice guys, perhaps it is because of the hitch height. As pointed out, all of the Eaglemate pics show low cruisers.

AM: AS for what the hell it's for, deer season is fast approaching and I ride the Strom.
 
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