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Old 02-10-2016, 08:17 PM   #57
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Dave (or MJ), I think it would be helpful if you looked at a simple force summation for the rear subframe. Consider the fore and aft forces due to acceleration and braking. Consider the lateral forces due to cornering. Consider the vertical forces that result in effective weight transfer to the front axle, and reduction in weight on the rear axle. When you attach the brace to the subframe (as compared to the unibody) all those forces are potentially reduced, not increased. That is why it doesn't make sense to think of increased forces on the bushings.

You express concern about the isolation mounts of the subframe, and proposed removing them in an earlier thread, but don't appear to be considering the isolation characteristics of the torque strut.

Sometimes engineers assist fabricators, especially if it is something that the fabricator hasn't built before. Since you mention credentials, out of interest, are you an engineer (Mech?), a fabricator, or both? You've got me beat on the 40 years, my engineering has been 30 years. I was pulling wrenches in a shop 40 years ago, though, and recall replacing rear subframe bushings about 36 years ago. It was a Jag with a V12, and it wasn't towing.

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Sorry to get back to you so late, but today was jump day.

I understand what you are driving at with the force summation. My concern here isn't just the added forces of the reinforcement arm. If my goal was to keep the current configuration that might be worth while pursuing, but you know what I really want here. It would be nice to know (if the current configuration is kept) what the new forces applied were. In the past I have use linear motion potentiometers to measure a systems motion over time. I remember seeing a similar device for force, but can't remember its name off the top of my head. You had discussed destructive testing, why not some non destructive testing that will provide the data. This would decide the issue once and for all or at least give food for thought.

I think what you are trying to say is sometimes engineers need to slap fabricators on the back of the head. I won't disagree with that. If it is to work at all it needs to be a two way street. The only engineering course I have been through is the Navy's Nuclear Power program. So maybe a minor one in nuclear engineering with emphasis on mechanical systems since it only covered one type of reactor design (PWR). A good engineer learns from the designs of others, so your career started when you got away with tearing something apart and back together without your parents finding out. You knew you had a vocation when you were handed a box of parts with no instructions and it worked when you were done. For me it was a VW bus engine.

Dave
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Old 02-11-2016, 05:25 AM   #58
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Just as a by the way as we're discussing each other's qualifications, you may wish to consider the qualifications of those who initially came up with these modifications. Andy isn't your average RV dealer.

If you want your qualifications to be respected you will have to extend that courtesy to others.
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Old 02-11-2016, 09:49 AM   #59
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Just as a by the way as we're discussing each other's qualifications, you may wish to consider the qualifications of those who initially came up with these modifications. Andy isn't your average RV dealer.

If you want your qualifications to be respected you will have to extend that courtesy to others.
I have learned a lot from Andy over the last few years. His posts are insightful and knowledgeable. It would be silly for me not to listen to what he says and learn from it. The man has forgotten more about trailers, airstreams and hitch setups than I will ever know. What I am not going to do is place him on a pedestal and worship the ground at his feet. He puts his pants on the same way we do. We all make mistakes and only an idiot doesn't try and learn from them.
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Old 02-20-2016, 08:40 PM   #60
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Well, I've made an appointment with Can Am RV in London, Ontario CA to get the hitch and related equipment installed. I'll post pictures and let y'all know how it goes!
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Old 02-20-2016, 08:45 PM   #61
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Great news. Looking forward to seeing how it all works out for you.
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Old 02-21-2016, 10:16 AM   #62
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This is such a great idea it might be good for us "live axle" types. So following the procedure to reinforce the hitch and promote WD, we should weld a reinforcement bar from the receiver shank to the bottom of the differential. What could possibly go wrong?
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Old 02-21-2016, 10:33 AM   #63
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Well, I've made an appointment with Can Am RV in London, Ontario CA to get the hitch and related equipment installed. I'll post pictures and let y'all know how it goes!
Sounds good tb. Get it done right the first time and enjoy the drive.
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Old 02-21-2016, 11:02 AM   #64
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This is such a great idea it might be good for us "live axle" types. So following the procedure to reinforce the hitch and promote WD, we should weld a reinforcement bar from the receiver shank to the bottom of the differential. What could possibly go wrong?
Now you're just trolling.
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Old 02-22-2016, 06:35 AM   #65
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This is such a great idea it might be good for us "live axle" types. So following the procedure to reinforce the hitch and promote WD, we should weld a reinforcement bar from the receiver shank to the bottom of the differential. What could possibly go wrong?

Showing my age here but this has actually already been done. In the 60's a common hitch was the "Axle Hitch". It was a Y shape yoke that clamped onto the rear axle of the tow vehicle and then had some chains bolted to the rear bumper to keep it from falling down at the rear. The torsion bars held it up when you were towing. They were popular with rental companies etc. because you could install one in minutes. I never towed with one we always removed them when a customer came in with one.

Though I had people tell me they worked better than you would think. I never heard of any falling off but the manufactures said they would void the rear axle warranty if one was used. They dented up the bottom of the bumper pretty good.

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Old 02-22-2016, 06:37 AM   #66
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Here is a typical Live Axle reinforcement with a spare tire below. The silver part is added.
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Old 02-22-2016, 10:46 AM   #67
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This is such a great idea it might be good for us "live axle" types. So following the procedure to reinforce the hitch and promote WD, we should weld a reinforcement bar from the receiver shank to the bottom of the differential. What could possibly go wrong?

Showing my age here but this has actually already been done. In the 60's a common hitch was the "Axle Hitch". It was a Y shape yoke that clamped onto the rear axle of the tow vehicle and then had some chains bolted to the rear bumper to keep it from falling down at the rear. The torsion bars held it up when you were towing. They were popular with rental companies etc. because you could install one in minutes. I never towed with one we always removed them when a customer came in with one.

Though I had people tell me they worked better than you would think. I never heard of any falling off but the manufactures said they would void the rear axle warranty if one was used. They dented up the bottom of the bumper pretty good.

Andrew T
Thanks for posting this Andy. From the picture in the next post the reinforcement is attached to the frame which is what I would expect. I did an internet search for "Axle Hitch" but could only find pictures of ones designed for Quads, Bikes and Motorcycles. Could this type of hitch have gone by another name? I would love to see an example of this. On a side note, I really couldn't believe what people have done to overcome towing obstacles. Some of the images were just mind blowing.
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Old 03-04-2016, 05:52 AM   #68
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[I]
Showing my age here but this has actually already been done. In the 60's a common hitch was the "Axle Hitch".
Andrew T
Back in the early 60's I recall the "Axle Hitch" as well. As a kid I remember my dad talking about them to customers but suggested they be avoided. Instead he sent folks to a reputable welding shop that did a good job of welding on a hitch.
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Old 03-11-2016, 10:12 AM   #69
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Today is the day! Our R320 is at Andy's shoppe for the hitch install! They said there's the possibility it might not get done by the end of the day which I'm hoping isn't the case since we made a special trip and hotel stay to get this done. Nonetheless, walking around their facility and seeing other vehicles they've done I'm excited to have them working on it!

BTW, met Andy in person; couldn't have been a nicer, more knowledgeable guy!
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Old 03-12-2016, 08:47 AM   #70
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It's done!

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Can't say enough good things about Can Am and the work they did on the hitch. Thanks To Andy and your team!
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