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Topic ClosedBent Axles/Camber Issues - Event Date: 08 May 2019 - 15 May 2019

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Poll Question: Bent axles or camber chamges of axles.
Poll Choice Votes Poll Statistics
1 [10.00%]
9 [90.00%]
This topic is closed, no new votes accepted

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StephenH View Drop Down
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Direct Link To This Post Calendar Event: Bent Axles/Camber Issues
    Posted: 10 May 2019 at 10:59am
The axle I had replaced did not have any visual bend at the attachment points but the camber of the tires was off with the tires splayed out at the bottoms and wearing the inside edge of the tires. That being said, adding some form of reinforcement to the outboard sides is critical to addressing the problem, whether the full-length V channel or either of the two outboard reinforcements.
StephenH
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ouR escaPOD mods
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marwayne View Drop Down
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Direct Link To This Post Posted: 10 May 2019 at 11:51am
If you jack up the axle in the middle you come to a point where you just lift the pod, release the jack the axle the goes back to where it was.
If you want something done right, do it yourself.
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mcarter View Drop Down
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Direct Link To This Post Posted: 10 May 2019 at 5:01pm
Off Grid,

I will check and reply.
Mike Carter
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Direct Link To This Post Posted: 10 May 2019 at 7:47pm
I think the numbers in the poll will not tell us if the Dexter axle is better if we don't know the percentage of Dexter to Lippert axle were installed on RPODs.
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marwayne View Drop Down
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Direct Link To This Post Posted: 10 May 2019 at 8:54pm
I had both Dexter and Lippert fail, however the Dexter was only rated at 3000#.
If you want something done right, do it yourself.
2011 RP172, 2016 Tundra 5.7 Litre, Ltd.


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offgrid View Drop Down
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Direct Link To This Post Posted: 11 May 2019 at 3:50am
Originally posted by texman

not sure i understand all of this.
  1. are the axles bending outbound of frame between wheel and frame?
  2. losing the camber at the center?
  3. or both?

if just the camber at the center, then couldn't the trailer be jacked up and put on stands at frame next to wheels and apply a jack to center of axle to return some camber?  

If outbound of frame, then why support the center of the axle?  Confused

All 3 depending on what kind of bump load you have.  The way the bending forces work on the axle tube which is a cantilever, you can have two cases. 

Case 1) If you hit say a speed bump with both wheels at the same time, then the stress on the axle is the same at and everywhere between the two frame rail support points. So the axle can bend anywhere or everywhere along that length. Outward from the supports the bending stress drops off, so bending at the very ends of the tube is unlikely. 

Case 2) If you hit a bump with one wheel only, the stress on the tube is max at the support nearest that wheel and tapers off both outbound and inbound from that point, so you are most likely to bend the axle right at the support.

Case 2 is probably more likely than 1 but both appear to be pretty common. 

One thing to point out is that the tube is really stiff and so does not deflect much at all before it yields under load. The point of yield is considered a bending failure because after that it won't spring back to its original shape. The points of maximum deflection are the ends and at the center, but it only deflects about a couple of tenths of an inch or so at either location before it fails. So its going to be hard to see the bend especially outward from the supports. Its easier to see if it has occurred inboard because you can run a string line and measure up in the center. At the ends its easier to see the bend as negative camber than it is to see it in the axle itself. 

Yes, you can push the axle up in the center to try to remove some camber, but that won't bend the axle ends back where they were it they were bent. Better (my opinion) to take it to an axle shop which has the proper equipment  to do it correctly. 

It doesn't help to only support the axle tube in the center. I think one thing that's maybe confusing folks is that the points of maximum deflection are not the points of maximum stress in this case. In a cantilever the points of maximum stress (the support points) are actually the points of zero deflection. The center is also one of the points of max stress in case 1, but all the other points between the two supports get loaded the same so supporting the center is only going to move the bending failure somewhere else. In case 2 the stress at the center of the axle is pretty low. 

It does help to reinforce the axle tube along its entire length of course, which is what "my" u bolted angle does. If I didn't support it continuously I would be creating a weak point at the center which would then become the point of failure in case 1.  

It does help to add support to the tube ends like both marwayne's and toyanvil's designs do. In those designs the supports can apply torque to the rpod frame rails, which potentially creates other problems. Marwayne and toyanvil have considered and dealt with that issue in different ways. 
 


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Direct Link To This Post Posted: 12 May 2019 at 9:19am
Originally posted by StephenH

 

I looked at those and saw that there were less expensive ones that did not have a housing. I don't know if any of them are made to withstand the conditions under the R-Pod as it is going down the road, especially if it is raining. If that is the case, this one would likely work since it is also Bluetooth and you could put it in a waterproof container strapped to the axle with a battery to power it. If you had a laptop with Bluetooth or a Bluetooth dongle, that would work.



In thinking about this some more I realized that the accelerometer does not need to be attached to the axle. The axle and frame are rigidly bolted together so it should be fine to attach the accelerometer to the trailer itself. That opens up using one of the cheap or free smartphone g force apps. We'd need to get one that records max events, and stick or strap the phone to the rpod floor directly above one of the axle to frame attachment points, or as close to there as possible.  That should do it. 
 


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bhesse View Drop Down
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Direct Link To This Post Posted: 01 Aug 2019 at 10:19pm
Do you have a parts list and lengths needed I would like to add this
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StephenH View Drop Down
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Direct Link To This Post Posted: 01 Aug 2019 at 11:20pm
My mods detail what I did. This is a direct link to my axle mod.
StephenH
Happy is the man that findeth wisdom,...

ouR escaPOD mods
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