Reply
 
Thread Tools Search this Thread Display Modes
 
Old 04-20-2019, 02:34 AM   #1
Rivet Master
 
Zeppelinium's Avatar

 
1975 31' Sovereign
1973 27' Overlander
1977 23' Safari
Palmer Lake , Colorado
Join Date: Oct 2005
Posts: 3,983
Send a message via Skype™ to Zeppelinium
Bumper bikes

I'm betting this simple modification is already a product on the market...

The bike rack designed for Airstream seems fragile to me. I've talked to a couple owners and I don't think it is up to the task and it's expensive. I like my Kuat bike rack, but I think any high quality hitch rack will work with this modification.

1. Get a piece of 4-1/2" x 1" rectangular steel tube. Weld 6" flanges at each end. Buy a hitch receiver and weld it at the bottom side in the center. Total cost $40 ($29 steel, $11 receiver, Airstream friend who is a welder). Paint it, if you like (it will be hidden). Sorry for the rotated photo.
Click image for larger version

Name:	rack_rack.jpg
Views:	130
Size:	94.6 KB
ID:	338604


2. Remove the bumper and slide the new hitch support in place. Drill two 1/2" holes through the frame at each end and bolt it in. You could do without the flanges and just weld the rectangular tube to the Airstream frame.
Click image for larger version

Name:	rack_frame.jpg
Views:	119
Size:	90.3 KB
ID:	338605

Click image for larger version

Name:	rack_slipfit.jpg
Views:	112
Size:	131.6 KB
ID:	338606

3. Cut a small relief (about 1/2" high) in the bumper for the receiver. You can use short machine screws and the original holes for the top attachment and either ignore the bottom attach points or drill and tap into the rectangular steel tube. (This all depends on the vertical placement of the rectangular tube. Mine is about 3/8" up from the bottom flange of the Airstream frame beams, but it could be flush with the bottom flanges.) You can see my Kuat bike rack is installed in this photo.
Click image for larger version

Name:	rack_cutout.jpg
Views:	105
Size:	85.7 KB
ID:	338608

4. An almost invisible installation and plenty strong for supporting a couple of bikes.
Click image for larger version

Name:	rack_fit.jpg
Views:	104
Size:	73.0 KB
ID:	338607

Zep
__________________

Zeppelinium is offline   Reply With Quote
Old 04-20-2019, 04:31 AM   #2
Rivet Master
 
SteveSueMac's Avatar

 
2012 27' Flying Cloud
W , New England
Join Date: Oct 2012
Posts: 6,730
It certainly looks tidy. I think every time this type of solution is discussed in these forums, the general consensus is that the Airstreamís construction doesnít tolerate such a hitch well (the amplified bouncing of the bikes on the hitch leads to the frame separating from the shell) and that the weight of the bikes and their distances behind the axles significantly increases the likelihood of sway based on mathematical formulas I donít understand but are meant to describe levers and moments and basically, itís apparently pretty problematic.

Some who have done such a mod say they have no problem with it. Others have tried it with less than happy results and come up with other solutions.

I think you do good work and wish you well. The purpose of this reply is to prepare you for the string of responses that may follow if history is any indicator of what to expect.
__________________

SteveSueMac is offline   Reply With Quote
Old 04-20-2019, 04:51 AM   #3
Rivet Master
 
2014 20' Flying Cloud
Long Island , New York
Join Date: Jun 2015
Posts: 10,173
Quote:
Originally Posted by SteveSueMac View Post
It certainly looks tidy. I think every time this type of solution is discussed in these forums, the general consensus is that the Airstream’s construction doesn’t tolerate such a hitch well (the amplified bouncing of the bikes on the hitch leads to the frame separating from the shell) and that the weight of the bikes and their distances behind the axles significantly increases the likelihood of sway based on mathematical formulas I don’t understand but are meant to describe levers and moments and basically, it’s apparently pretty problematic.

Some who have done such a mod say they have no problem with it. Others have tried it with less than happy results and come up with other solutions.

I think you do good work and wish you well. The purpose of this reply is to prepare you for the string of responses that may follow if history is any indicator of what to expect.
Well said . . . thank you SSM for a cogent summary!

Zepp, FYI here are the search results for "rear hitch bike rack" --

https://www.google.com/search?q=rear...com&gws_rd=ssl
"rear hitch" -- https://www.google.com/search?q=rear...=airforums.com

And here is one of the main threads:

http://www.airforums.com/forums/f464...er-174590.html

If you want to expose your family and the motoring public to unnecessary risk, by adding excessive weight [beyond Airstream's design parameters] that far behind the axles, feel free . . . IMO.

Good luck,

Peter

PS -- To go into the proposed modification with eyes wide open, you might want to read the many Sway/Roll-over threads like:
-- Quebec roll-over:http://www.airforums.com/forums/f48/...ec-153984.html
-- Out of Control Sway: http://www.airforums.com/forums/f238...ay-152451.html

OTRA15 is offline   Reply With Quote
Old 04-20-2019, 08:44 AM   #4
Rivet Master
 
A W Warn's Avatar

 
2000 25' Safari
1999 34' Excella
Davidson County , North Carolina
Join Date: Aug 2006
Posts: 3,647
I made a similar hitch. It hung below the tray but attached to the side rails like yours.

I did not like the way it performed (too much bounce), And, because of the increased chance of sway, I took it off. It's still laying around somewhere. I need to repurpose it for some other use.
Click image for larger version

Name:	hitch exstension on airsteam.jpg
Views:	93
Size:	311.1 KB
ID:	338621
__________________
Alan
2014 Silverado 1500 Crew Cab 5.3L maximum trailering package
A W Warn is offline   Reply With Quote
Old 04-20-2019, 08:59 AM   #5
Rivet Master
 
Al and Missy's Avatar

 
2002 30' Classic S/O
Melbourne Beach , Florida
Join Date: Nov 2013
Posts: 3,353
Not that anyone asked, but my assessment is that it is not so much the weight as it is the distance behind the bumper and the lack of support to prevent bouncing. I think a bike rack that emulated the design of the Airstream-approved rack, i.e. bikes above the bumper instead of behind, and support attachment to the ribs and skin at the top, would work much better.

I put a front receiver on my truck and used a good quality bike rack in it but I was not happy with the amount of bounce I saw. It would be worse on the rear of the trailer due to the porpoising and the distance to the wheels. There are videos on the web showing the bouncing of bikes on a rack behind a white box. The amount of bounce depends, obviously, on the stiffness of the mount and rack, but my rack was a fold-down version that had quite a bit of slop in the pivot point.

We gave up and bought folding bikes that ride in the back of the TV.

Al
__________________

"You cannot reason someone out of a position they have not been reasoned into"

Al, K5TAN and Missy, N4RGO
2002 Classic 30 Slideout
S/OS #004
2013 Dodge 2500 Laramie 4x4 Megacab Cummins
2001 Safari 25 RB Twin (Gone, but not forgotten)
WBCCI 1322, TAC FL-39, AIR 82265

Al and Missy is offline   Reply With Quote
Old 04-20-2019, 10:00 AM   #6
Rivet Master
 
2007 27' International CCD FB
San Diego , California
Join Date: Sep 2014
Posts: 1,101
I agree with you that much of the stresses is due to the punishing bouncing that could occur. It is as important of a factor in the design as anything.

Factors to ride quality at the rear of the trailer include the tow vehicles ride quality itself and what forces it projects into the tongue, that are further magnified at the rear position). The quality and condition of the trailers axles. And additional play in the receiver, bike rack, and bike mounting system could further exacerbate it.

In my particular setup, my tow vehicle is plush riding. I added a hitch tightening bolt within the bike rack receiver. And utilize a bike rack that is strong and rigid to minimize play. My rear facing camera on the AS shows very little movement of my bikes under tow.

To your point, many standard hitch bike racks are not rated for use at the back of the trailer.
__________________
Boondocking option package:
'07 27FB Ocean Breeze "See Turtle", 3" lift
'09 Lexus LX570, on 33's
Tongue Mount Honda eu2200i - Rear Hitch - Underbelly Storage - Blizzard NXT w/ EasyStart - 3" Lift - 6" Fan Controller
pteck is offline   Reply With Quote
Old 04-20-2019, 11:16 AM   #7
Rivet Master
 
Zeppelinium's Avatar

 
1975 31' Sovereign
1973 27' Overlander
1977 23' Safari
Palmer Lake , Colorado
Join Date: Oct 2005
Posts: 3,983
Send a message via Skype™ to Zeppelinium
Quote:
Originally Posted by SteveSueMac View Post
...the weight of the bikes and their distances behind the axles significantly increases the likelihood of sway ...
I see lots of people worried about sway. I've never seen it, even when maneuvering aggressively. But the two vehicle is a diesel and I think that makes a big difference. Back in the day when we were towing with a Ford Explorer, anti-sway bar and max of 55 mph was the order of the day.

The bikes are light, but the Kuat bike rack is heavier than they are and it has an articulated joint for folding up. I would guess the whole thing will weigh just a few pounds more than a second battery, but unfortunately is further from the axles.

In one of the recommended threads, I saw Barts say that a Sherline tongue weight gauge is an essential tool. I just ordered one.

Bounce is another issue. I guess I'll get a camera on it. But I have a front hitch on the diesel and the bounce up there was pretty terrible (and the bikes totally blocked the view forward at night). I don't think it'll be any worse in the back, but a test tow will tell the tale.

I'm thinking the best answer is to stay away from that horrible section of the 405, just as you're leaving the Valley heading south.

Zep
Zeppelinium is offline   Reply With Quote
Old 04-20-2019, 11:54 AM   #8
CLOUDSPLITTER "Tahawus"
 
ROBERT CROSS's Avatar

 
2003 25' Classic
Zanadude Nebula , Milky Way
Join Date: Jun 2007
Posts: 13,323
Images: 1
If you try it and it works for you it's good👍...If someone else tries the same thing and it's not good for them👎...it's also good.👍 🤔
TETO

Bob
🇺🇸
__________________
"We are all here on earth to help others; what on earth the others are here for I don't know."
W. H. Auden


"The hardest thing about Airstreaming, clearing your head and accepting how others feel itís supposed to be done"Ö..
Amanamus


"Tahawus"
ROBERT CROSS is offline   Reply With Quote
Old 04-20-2019, 12:03 PM   #9
3 Rivet Member
 
2019 28' Flying Cloud
2014 22' FB Sport
Davie , FL
Join Date: Feb 2019
Posts: 222
Sway should not be a problem. If you compare the inertia of the bikes and rack with the inertia of the trailer as a whole you will see that it will not make a big difference. However if you are concerned then you could move some other cargo in the rear the trailer to a point closer to the axles to compensate.
out of sight is offline   Reply With Quote
Old 04-20-2019, 12:29 PM   #10
Rivet Master
 
2007 27' International CCD FB
San Diego , California
Join Date: Sep 2014
Posts: 1,101
The point is to not get complacent with load on the rear of a trailer. Even if you have an HD truck. It's that attitude that will lead to an incident.

I regularly camp with a group where we take turns towing a communal trailer. It's a small to medium size utility trailer with cooking/bbq and camp equipment. Probably 2-3k lbs at most.

Even this little trailer when loaded out wrong and the heavy stuff behind the rear axle of the trailer WILL cause a newer F250 to sway. It's not a joke and an HD truck has never been a silver bullet in this regard to compensate for a badly loaded trailer.
__________________
Boondocking option package:
'07 27FB Ocean Breeze "See Turtle", 3" lift
'09 Lexus LX570, on 33's
Tongue Mount Honda eu2200i - Rear Hitch - Underbelly Storage - Blizzard NXT w/ EasyStart - 3" Lift - 6" Fan Controller
pteck is offline   Reply With Quote
Old 04-20-2019, 01:39 PM   #11
3 Rivet Member
 
SilverWind's Avatar
 
2017 25' International
1968 17' Caravel
Los Osos , California
Join Date: Nov 2013
Posts: 195
I've had the Fiamma/Airstream bike carrier on three Airstreams. Install them correctly and they work well. Never had a failure. Weigh only 25 pounds.

Pay attention to the 75 pound combined bike weight limit. Don't carry your heavy e-bike.

I've seen two rear receiver type carriers, installed by Airstream dealers, fail from cantilever torque induced weld failures shortly after installation. This is a cost saving DIY project that could cost a lot more in the end.
They may also contribute to sway because of the weight concentrated further to the rear than the engineers intended.
SilverWind is offline   Reply With Quote
Old 04-20-2019, 03:22 PM   #12
Rivet Master
 
65CV's Avatar
 
1959 26' Overlander
Western , Massachusetts
Join Date: Sep 2005
Posts: 1,465
Images: 6
We've towed over 20K miles with two bikes on the back of our 26' Overlander without an issue. Our receiver was installed differently, but I'm sure it was welded as solid as Zepp's. As an avid fan and copier of Zepp's designs, I would not be worried. We've never had sway issues with two older mountain bikes on the rear hitch. We use a Reese Dual Cam High-Performance Sway Control.

There are other options if you don't want to expose the bikes to the weather:

If you are concerned and/or able to carry your bikes inside the trailer, search for lcurrie's post. She installed a fork mount to hold the bike inside the trailer.

Now that I carry a fancy carbon bike, I had a plate made that I bolted into the back of my Crew Max. It features a fork mount that holds the bike inside the truck. We just fold the seats up for transporting the bike and fold them back over the fork mount when we need the seats for passengers.
65CV is offline   Reply With Quote
Old 04-20-2019, 03:59 PM   #13
Rivet Master
 
Zeppelinium's Avatar

 
1975 31' Sovereign
1973 27' Overlander
1977 23' Safari
Palmer Lake , Colorado
Join Date: Oct 2005
Posts: 3,983
Send a message via Skype™ to Zeppelinium
Quote:
Originally Posted by 65CV View Post
Now that I carry a fancy carbon bike, I had a plate made that I bolted into the back of my Crew Max. It features a fork mount that holds the bike inside the truck. We just fold the seats up for transporting the bike and fold them back over the fork mount when we need the seats for passengers.
I like! But I only have an X-cab, not a crew cab. Is that big enough or do I need to do the experiment myself?

Zep
Zeppelinium is offline   Reply With Quote
Old 04-20-2019, 04:04 PM   #14
Rivet Master
 
Zeppelinium's Avatar

 
1975 31' Sovereign
1973 27' Overlander
1977 23' Safari
Palmer Lake , Colorado
Join Date: Oct 2005
Posts: 3,983
Send a message via Skype™ to Zeppelinium
Quote:
Originally Posted by ROBERT CROSS View Post
If you try it and it works for you it's good👍...If someone else tries the same thing and it's not good for them👎...it's also good.👍 🤔
Bob, I am entertained. Or as Calvin would say, "let's go exploring!" I'll get back to this thread once I get my tongue scale and some actual numbers...

Zep
__________________

Zeppelinium is offline   Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
E Bikes X2 Bikes On Top Of Truck Bed mythbuster88 On The Road... 11 03-01-2019 10:46 PM
If not on the rear bumper, where to put the bikes? Savage68 All Argosy Trailers 43 11-14-2014 06:35 PM
Kayaks and bikes jordandvm Off Topic Forum 42 02-26-2009 09:12 PM
Bikes and Bambi Trevor Davies 1997 - 2004 Bambi 13 12-22-2004 07:07 PM
How Do U Bring Bikes Along? Steve Heywood On The Road... 30 04-06-2004 10:37 PM


Featured Campgrounds

Reviews provided by

Disclaimer:

This website is not affiliated with or endorsed by the Airstream, Inc. or any of its affiliates. Airstream is a registered trademark of Airstream Inc. All rights reserved. Airstream trademark used under license to Social Knowledge LLC.




Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 02:51 AM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.