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Old 06-03-2018, 05:20 PM   #21
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Your 30' classic has a GVWR of 10,000 lbs. If you are anywhere south of that, loaded and wet for camping you are fine with up-to 100lbs on the bumper so long as you keep other stuff under the bed and in the trunk minimal.

As you've noted 100lbs out back will not affect towing on a rig that is that heavy. Plenty of people fill their trunks full of stuff that is >> 100 lbs. Yes there is leverage off the bumper, but still...

If late model airstreams where so fragile such that on a 10,000lb GVWR chassis and semi-monocoque structure with 100lbs extra off the back would cause frame fatigue and separation we'd all be in trouble ...

That being said I wouldn't put anything else rearward of the coach and personally, and I'd keep the trunk contents light... And as a cyclist for what it is worth, I just prefer to carry my bikes where I can see them using a more traditional rack system that holds the fork and rear wheel - in the bed of my truck but it's not for shell/frame integrity reasons.

This is a sensitive topic for me - I did a lot of engineering analysis with Airstream, custom commercial uplifters Timeless Travel Trailers here in Denver and with hands-on experience from Lew Farber after making the decision to load 330lbs of lithium batteries and other items under the bed of my 2017 30' international with GVWR of 8,800lbs (the International has the same frame sub-structure as the 10,000lb GVWR classic - only really different is different dexter axles).

In the end I made an informed decision to move forward with adding weight under the bed (understanding that this has different effects than weight off the back as it is contained within the shell). I place a large amount of weight under the bed and I was still at 975lbs tongue weight which is 11.6% of my trailer weight of 8,400 loaded, wet and ready for camping. I've towed 3,000 miles with the extra weight and she tows well even in high cross-wind situations and without a propride. Here are some photos of my setup... I just wouldn't be too concerned with a bike rack if you manage your payload forward and rear of the axles appropriately . The structure can support it.
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Old 06-03-2018, 05:47 PM   #22
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Excellent reply wulfraat!
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Old 06-03-2018, 05:55 PM   #23
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The Fiamma (Airstream designed) bike rack is supported by the frame rails where they attach to the bumper on either side as well as to the body uprights on either side. Force is distributed to four points.

The OP's hitch mount as shown has a single attachment point and is cantilevered which focuses the hundred pounds on one point. The 25 pound Fiamma will accept 75 pounds of bikes, for 100 pounds, again focused on four points.

A friend of mine had the same sort of receiver mount rack as shown by the OP. It was installed by an Airstream dealer in Southern California. The welds failed on the second trip.
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Old 06-03-2018, 05:55 PM   #24
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It sounds to me that you have 2000 miles more experience than any of the naysayers. I have 3 seasons on my setup and the sky has not fallen yet.
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Old 06-03-2018, 06:41 PM   #25
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Originally Posted by interstateflyer View Post
The Fiamma (Airstream designed) bike rack is supported by the frame rails where they attach to the bumper on either side as well as to the body uprights on either side. Force is distributed to four points.

The OP's hitch mount as shown has a single attachment point and is cantilevered which focuses the hundred pounds on one point. The 25 pound Fiamma will accept 75 pounds of bikes, for 100 pounds, again focused on four points.

A friend of mine had the same sort of receiver mount rack as shown by the OP. It was installed by an Airstream dealer in Southern California. The welds failed on the second trip.
Agreed. Note though that the Airstream rack is supported vertically at the two bottom points. The two top attachment points don’t carry any weight, but they control fore/aft movement at the top of the rack, which would translate into a bending moment at the lower welds.

That bending can result in fatigue failures.

Whenever someone focuses on weight alone, they are focused on two dimensions. We live in a three dimensional world, though.
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Old 06-03-2018, 07:13 PM   #26
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Agreed. Note though that the Airstream rack is supported vertically at the two bottom points. The two top attachment points don’t carry any weight, but they control fore/aft movement at the top of the rack, which would translate into a bending moment at the lower welds.

That bending can result in fatigue failures.

Whenever someone focuses on weight alone, they are focused on two dimensions. We live in a three dimensional world, though.
Good point.
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Old 06-03-2018, 07:35 PM   #27
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Bougeois,

Seems like you missed reading the very valuable Rollover in Idaho and Quebec threads linked earlier? They are long but might save your family's lives:

Your simplistic testing and reasoning -- and disregard of Airstream's very limited allowance of a Fiamma bike rack mounted over the bumper [and not cantilevered behind it, where the force of the mass increases according to the square of its distance from the rear axle] -- ignores so much physical reality it is hard to summarize briefly.

One is reminded of the little train who made it over the mountain repeating the mantra, "I think I can, I think I can . . . "



Unfortunately such personal conviction here cannot change the physics of hanging a large weight like this way behind where Airstream has intended them to be. You might want to read another long thread -- Out Of Control Sway:

http://www.airforums.com/forums/f238...ay-152451.html

Good luck, because sooner or later your setup is going to need luck to avoid serious injury or worse IMO.



PS -- Yes the language above is a bit direct and confrontational, because IMO you are creating a dangerous situation every time you take your rig on the road. Please take the time read the 3 threads linked above, and then reply that you still feel confident in your setup. Oh, also, please let us know when and where you will be on the road, so we can avoid being in your path.
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Old 06-03-2018, 07:48 PM   #28
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Originally Posted by Flying tulip View Post
It sounds to me that you have 2000 miles more experience than any of the naysayers. I have 3 seasons on my setup and the sky has not fallen yet.
Then you have also been lucky IMO. Please read the 3 long rollover and sway threads just referenced. Bragging about getting way with something does not reduce the risk to the rest of us when you tow a rig which exceeds Airstream's design parameters.



PS The same rollover/sway links were provided after your comment in another bike rack thread.

Quote:
Originally Posted by Flying tulip View Post
George Hernandez out of NY installed a receiver that comes out of the rear bumper to take my 1upusa bike rack. No problem with weight or damage to trailer but some damage to bike rack. Next time my trailer is at George's shop I will have him stiffen it a little more .
If you click on the orange arrow in the quote above, and go to that thread, there is further discussion about the Fiamma bike rack, and the physics etc. involved in these issues.
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Old 06-03-2018, 09:35 PM   #29
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I also tow with a suv on Goodyear tires. I am doomed
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Old 06-03-2018, 09:37 PM   #30
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I followed a trailer last week with bikes on a hitch mounted on back. The bouncing of that bike rack was INSANE. I imagine the owners don’t even realize it. I quickly understood why so many bike racks specify not to be put on the back of a trailer. There is no way they can hold up. The one I was following will surely be breaking off and hopefully not causing damage or worse for drivers behind. I would at least do what the earlier post said and find a way to strap the bikes from a point higher up as well to try to mitigate some of that springy bouncing.
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Old 06-03-2018, 09:44 PM   #31
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Bike rack

A modern 30’ airstream can handle it if you don’t overload the rear of the coach behind the rear axle with a bunch of other heavy “stuff” - but nevertheless I choose to carry the bikes where I can see them [emoji4]
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Old 06-03-2018, 10:57 PM   #32
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I would love to know how many “safety alert”, bashing my bike rack are even running a propride hitch! How many of you ever went to a weight station and check your axle weight? Not sure how this turned into this but I live in Memphis and have much better odds of being shoot than a stupid bike rack killing me. All this was is to show an idea that I did and if anyone was thinking of doing something similar. Good God!
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Old 06-03-2018, 11:07 PM   #33
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Quote:
Originally Posted by interstateflyer View Post
The Fiamma (Airstream designed) bike rack is supported by the frame rails where they attach to the bumper on either side as well as to the body uprights on either side. Force is distributed to four points.



The OP's hitch mount as shown has a single attachment point and is cantilevered which focuses the hundred pounds on one point. The 25 pound Fiamma will accept 75 pounds of bikes, for 100 pounds, again focused on four points.



A friend of mine had the same sort of receiver mount rack as shown by the OP. It was installed by an Airstream dealer in Southern California. The welds failed on the second trip.


We took a 6ft sq tube and put it in receiver and had “two” 200lbs+ guys from our shop and jumped up and down. Did it move it, yes. Did it bend or brake! The sky isn’t falling. Shitty welds fail.
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Old 06-04-2018, 04:42 AM   #34
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Originally Posted by Bougeois View Post
I would love to know how many “safety alert”, bashing my bike rack are even running a propride hitch! How many of you ever went to a weight station and check your axle weight? Not sure how this turned into this but I live in Memphis and have much better odds of being shoot than a stupid bike rack killing me. All this was is to show an idea that I did and if anyone was thinking of doing something similar. Good God!


I hear you. People are genuinely trying to look out for your best interests even if you haven't asked for that or it doesn't feel like that to you.

For the record - I don't think I bashed your rack. I did ask if you noticed a difference in handling. That's because of the number of threads I've read in these forums of people who've done that and experienced sway, accident scenes with setups like this, the physics of a lever like that over the rear of a trailer, Airstream's warning not to do it for frame damage and their only endorsed bike rack solution which places the bikes in a different position.

You can find my postings of my CAT scale tickets here as well as my use of a ProPride.

Maybe it really works for you. There are just so many reasons not to do it this way, it's hard for people to imagine there's a "lottery winner" who escaped the physics. Since I'm no PhD in the area, I can't judge....

Good luck!
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Old 06-04-2018, 05:30 AM   #35
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I had a similar bike rack set-up on my old white box trailer. It created so much sway, that I took the bikes off 30 minutes into the first trip. Never used it again on the camper.
I am confident that even in Memphis you will be safe from your bike rack, because you will be up front...
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Old 06-04-2018, 11:25 AM   #36
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B - I am sorry you feel like you’re unduly picked on. I’m absolutely positive you do in fact have a significant risk of being killed in Memphis on any given day for no reason at all than by loosing control over the bike rack. IMO there have been too many documented cases of crashes, serious injury and so forth to take that chance when the engineers at Airstream only recommend one source. I’m positive that you would not knowingly place anyone at risk but please reconsider your current set up. Me and the others who have expressed concern only have your best interest at heart.
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Old 06-04-2018, 04:21 PM   #37
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B - I am sorry you feel like you’re unduly picked on. I’m absolutely positive you do in fact have a significant risk of being killed in Memphis on any given day for no reason at all than by loosing control over the bike rack. IMO there have been too many documented cases of crashes, serious injury and so forth to take that chance when the engineers at Airstream only recommend one source. I’m positive that you would not knowingly place anyone at risk but please reconsider your current set up. Me and the others who have expressed concern only have your best interest at heart.


Thanks. BTW there are lots of things in life that will kill ya. I talked to Shawn at propride about it and he’s done LOTS of engineering on trailer sway and said no problem. I load everything forward of axels, been to the weight station at least 6 times with different loads to see how weights effect tongue weight and axle weight and trailer weight. It’s not like I just put it on and away I went. Its just think it’s funny how people eating their high fructose corn syrup biscuit and gravy bacon grease breakfast heart attack waiting, wants to tell me how I’m going to die over a 100lb bike rack. 🤣 but thank you for you concern. Now off for my family’s 5000 miles Airstream’s Adventure. Cheers.
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Old 06-04-2018, 04:32 PM   #38
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If you have a ProPride setup properly, load properly as you describe, and have your scale numbers right, I see no issue.

There is some residual concern that loading outboard of the frame aft MAY possibly put extra strain on the frame and shell back there. If you are not carrying a ton of bikes, it's probably not an issue. At worst, you may need to reinforce it a bit more. As long as you have at least 10-15% of total AS loaded weight on the hitch, you should be fine.

I've hauled my rig with a ProPride for lots of miles, loaded and set up like you describe, and sway has never been an issue...I adjust WD bars to assure decent handling and front TV front end weight restoration, and I'm good to go.

I have more problems with a too-small engine slowing us down on uphill runs...but I'm patient, and NEVER in a hurry. Enjoy!
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Old 06-04-2018, 05:46 PM   #39
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Note the date on post #12 of the tread and the tread it references you to.

http://www.airforums.com/forums/f209...per-39529.html

That rake has at least 100,000 miles on it.

While it is for 2 bikes I have carried 4 with it.


So far the only repair has been replacing the wooden blocks that mount it to the bumper. Wood dose not last as long a aluminum.
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Old 06-04-2018, 07:10 PM   #40
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I'm a lurker....my first post.

There are two separate concerns here, one is the integrity of the hitch itself, and two is the affect on towing/sway. It appears that people with concerns are combining these two issues. I suppose if sway started, then the rack may fail due to the sway forces on the rack, but the OP stated he has a ProPride. If he has sway, something else failed on the hitch and he has bigger problems.

First the integrity of that hitch....if properly welded to the frame that hitch with a 2" receiver will have a minimum rating of 500lbs, probably more. The combined weight back there can't be more than 120lbs, exponentially under the rated weight. I have seen bikes on racks with a 1 1/4 inch receiver. Either it is rated for it or it isn't, properly installed his is fine.

The second issue is with sway. Lets ignore the Propride for a minute. A trailer doesn't know what it is being towed by....all it knows is it is towed by a ball. Whether that ball is connected to a SUV or full ton. I see a lot of bad setups covered up by big trucks. Of course a heavier, stiffer truck will handle sway once it starts, you are still going to soil your pants if it starts, especially on a two lane road, and are still putting you and others at risk just "loading and going".

Semis run weight and balance almost every load, cars never do. Somewhere between the two extremes weight and balance should be done. If someone mounts a 100 lb bike rack, and that sets up sway, they were unacceptably and dangerously close to sway to begin with. Nobody should be towing in that condition. The only way for sway to start is with tongue weight WELL south of 12%, most likely 8%. The safety police on here should be able to belch out their actual measured tongue weight within a percent or two, or they have nothing to stand on.

The design of the Airstreams lend to loading inconsistencies compared to more standard travel trailers which almost all have front storage areas creating additional tongue weight and preventing sway.

The OP stated he has weighed his rig on several occasions, I assume because he got good advice from someone to do so, enlightening him to the loading issues with Airstreams and towing in general.

If that bike rack doesn't lower his tongue weight below 10%, and he has his hitch set up properly to return an actual MEASURED amount of weight to the front axle maintaining steering effectiveness, sway won't start, regardless if he put 500 lbs back there. Kudos for him for knowing his weights. He is far safer than anyone who hasn't actually weighed their rigs. Add on the Pro Pride hitch and he is far safer than 98% of the rigs out there.
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