FB - move batteries to rear of trailer

[Ohiobrits]

Originally Posted by mojo

If you want to gain payload, you can always get rid of the bathtub muffler and reroute the exhaust with two smaller mufflers. Cuts out about 50lbs. Plus if you decide to go to CanAm, you won't have their hitch extension wrapped underneath the muffler lowering clearance.

Thanks mojo. A Can-Am style hitch reinforcement is on the list to do. I'm also planning on removing the "suitcase" rear muffler as you suggest. Apparently with this being a turbo diesel with 2 cats and a particulate filter there is essentially no increase in exhaust noise by dropping that. Also the space saver spare and tools under the hatch in the trunk weight 50 lbs - jack will be transferred to the TT when towing. I intend to carry a full size spare in the TT in place of the space saver. There should be about 100lbs there I think.

[KJRitchie]

My 2008 Clasisic 25fb has aluminum 30lb tanks. I have 106lbs of batteries and sometimes I carry 2 bikes on my Arvika bike rack system that sit over the propane tanks. I use an Equalizer hitch. My Tundra doesn't seem to complain. I don't think moving the batteries under the front bed is worth it in my case. I'd have to switch to AGMs close to $600. The batteries would only be back a couple of feet. I don't store anything under the bed and if I do it would be clothes for extended trips. If I was that worried I don't see a workable solution except to downsize to a 23fb or ditch my Tundra for a 3/4t truck. Airstreams are heavy trailers for their size and we can't get around that.

Kelvin

[TinTin]

Originally Posted by dkottum

Although I see published tongue weights for the 23FB, 25FB and 27 FB to be lighter than their rear bed counterparts, I would think they would tend to load heavier in the front because most of the storage is forward of the axles.

So FB or RB would seem to equalize in hitch weight when loaded for travel?

If so the issue for light duty trucks and and SUVs is still hitch weight, as it impacts their payload and receiver capability. I have done some things to reduce my own as posted earlier in this thread. Battery relocation or lightening, aluminum propane tanks, and (re)moving the spare tire and carrier would certainly make a significant difference, taken together with a few other changes.

I would like to see a goal of near 800 lbs hitch weight onD the coupler ball for our 25' FC. I don't think that is unrealistic from the starting point of 835 lbs at the factory.

Doug: You're right on about loading/storage of the FB and RB. Engineered exactly the way you describe.

[mojo]

Originally Posted by Ohiobrits

Thanks mojo. A Can-Am style hitch reinforcement is on the list to do. I'm also planning on removing the "suitcase" rear muffler as you suggest. Apparently with this being a turbo diesel with 2 cats and a particulate filter there is essentially no increase in exhaust noise by dropping that. Also the space saver spare and tools under the hatch in the trunk weight 50 lbs - jack will be transferred to the TT when towing. I intend to carry a full size spare in the TT in place of the space saver. There should be about 100lbs there I think.

Your on the right track...

[Ohiobrits]

Originally Posted by mojo

Your on the right track...

Yep. No impact in ground clearance either with this exhaust arrangement and a "straight shot" hitch reinforcement.

I just had another GREAT idea to improve my payload.....tell my wife to lose weight....wait....no...thats a bad idea....in fact, thats not even funny

[jcl]

Originally Posted by Ohiobrits

Here are a few calculations on what is possible relative to various weight reductions suggested so far - approximate only since I do not have any of the actual dimensions, weights etc and its been too many years since I did these kind of calculations:-

I am interested that your calculations are with respect to tongue weight, but don't consider rotational inertia about the trailer axles. Potential trailer sway would seem to be impacted by that inertia. In that sense 100 lbs on the tongue offset by 100 lbs at the trailer bumper would not be equivalent to 200 lb over the trailer axles. I can see moving the batteries closer to the trailer axle, but deliberately placing them further aft may benefit tongue weight at the expense of towing stability. Just something to think about. Interesting thread, lots of good ideas. Good luck with the project.

Jeff

[Rolland]

There is another issue I have seen while looking at other tv's at rally's. The distance from the ball to the tv's rear axle is critical in load carrying. I have seen a lot of hitches with long shanks before the ball, and that greatly reduces your load carrying capacity. Besides moving weight further aft in the trailer to reduce tongue weight, consider shortening the hitch on the tv as much as you can, it makes a huge difference in weight carrying ability without making the tv squat, and handling.


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[Ohiobrits]

I located the 2014 Flying Cloud owners manuals, they are on the Airstream website in the Service section.

The wiring diagrams show 4ga wire going from the battery to the inverter, other wires are 6,8,10 and 12ga.

I also checked with Can-Am and they use 2ga when moving batteries to the rear of an FB. They also route the wires on the underside of the TT. They said they would warranty the work if done by themselves so no impact on warranty for a new Airstream.

Looking for other ideas to reduce hitch weight, I had a look at the Airstream Europe website. They have 5 models ranging from a 22ft 4000lb TT to a 27ft model that weighs in at about 6000lbs. They have 2, smaller propane bottles mounted on the A frame tight up against the front wall. It looks like the batteries are probably mounted inside the TT. MAX, not to exceed, hitch weight is 331lbs for all of them which works out between 4 and 6% hitch weight. Based on our convention to not go below 10% or suffer sway issues, these TT should all have major stability issues but that sounds like a topic for another forum.....

Anyone want to give 4% hitch weight a whirl and report back?

Joking aside, thanks for all the input - I think I have what I need for now.

[Andrew T]

Just a little background on where the higher hitch weights have come from. The 25FB started out as a Safari model with no wrap windows in the front and lighter glass every where. A lighter mattress, optional spare and a single battery. As it gradually changed to the current Flying Cloud and International models the hitch weight increased getting us to where we are now. This means you can remove quite a bit of hitch weight without compromising handling.

You can ground the battery through the body but if your running one wire it is no more work to run a second. Now with LED lights the current loads are much lower than they were historically. If you have an Invertor though it should be moved closer to the batteries. There should be a fuse or preferably a breaker near the batteries. You may also want a Kill switch in the line for storage but connect any solar panels on the battery side of the kill switch.


We always change to Michelin tires when we remove the spare so the odds of a flat are almost nil. Through the 60's and 70's most Airstreams were built without a spare since they can run on three wheels so this is nothing new.

The Porsche load capacity is artificially low as the Q7 which has identical componentry is quite a lot higher due to the third row of seats. It is likely as low as it is because it would be less stable at 100 MPH if loaded that heavy as a solo vehicle.

I just received this email from a Customer if it helps. They picked up their combination in August.

Howdy,

Just arrived this Thursday at Fun-N-Sun in Sarasota FL – we had a chap pop by our site yesterday and he said that he watched us come in from the highway and was amazed at how level the trailer and car were while towing. We were also happy with the travels – towed the classic at 70 mph the entire way (or posted speed limit) and the Audi was spectacular while the Airstream was easy to forget behind the Audit as it was so smooth. You did a great job setting the tow system – we are extremely pleased

Happy new Year,

Jim

Now I have a question

I did some looking into Lithium batteries and was told there was some risk of fire with them so I was not sure I wanted one inside the trailer or behind the LP tanks. Has anyone else found this?

[SafariSS]

Here are a few calculations on what is possible relative to various weight reductions suggested so far - approximate only since I do not have any of the actual dimensions, weights etc and its been too many years since I did these kind of calculations:-<br />
<br />
Assuming a hitch to axle center line dimensions of 211 inches for the 25FB (scaled from a photo ).<br />
<br />
<b>Batteries: - </b><br />
<br />
Assuming 2 x 53lb batteries = 106 lbs total installed 24 inches from the hitch, removing them will reduce hitch weight by 94lbs and remove 12lbs from the axles.<br />
Moving the same 2 batteries inside under the bed at 48in from the hitch adds back 82lbs to the hitch and 24lbs to the axles. Probably not worth the effort.<br />
<br />
I looked up lithium batteries, I'm not sure what the direct equivalent is for the lead acid ones installed but they are touted at 70% lighter.Deep Cycle Lithium Batteries. Assuming 2 batteries at say 40lbs instead of 106 the following applies: - <br />
<br />
Leave in current box location outside, this adds 35lbs to the hitch and 5 to the axles - nice saving on the hitch of about 59lbs. Move under the bed and the hitch load is 31lbs, a savings of about 63lbs. Again probably not worth the effort to relocate but well worth the effort to use Lithium so long as the cost is not ridiculous. <br />
<br />
<b>Gas bottle reductions / changes: - </b><br />
<br />
Assuming removing one full 30lb bottle (actual weight full = 54lbs) positioned 12in from the hitch will reduce hitch weight by 51 lbs and axles by 3. Nice reduction here if you will use hookups and don't need much propane. Aluminum and composite bottles are available but did not look too much lighter than the steel ones from what I could see but would save maybe 8-10lbs per tank. <br />
<br />
Moving the 2 lead acid batteries to the rear of the trailer removes about 135lbs from the hitch since the battery weight is now behind the axle and actually tries to lift the hitch a bit. I guess that is why this option is attractive (installation issues and cost aside).<br />
<br />
<b>TT Spare</b><br />
<br />
Removing the TT spare at about 50lbs and 48in from the hitch removes about 37lbs from the hitch. <br />
<br />
Combining TT spare deletion with batteries in the rear you get about 170lbs of tongue weight relief, add a 70lb hitch and the 835lb hitch weight would be (very roughly) 735lbs dry, unloaded. <br />
<br />
Based on various posts I have read, hitch weight for the 25FB goes up about 100 - 150lbs when fully loaded with water etc. Either dry or fully loaded therefore would still be above the 10% hitch weight so would seem reasonable. <br />
<br />
<b>Other options?</b><br />
<br />
Out of interest the 27FB has a slightly lighter tongue at 791lbs which gives another 44 lbs of savings for those looking to save a few lbs with zero effort....if not zero $, those extra inches cost extra $.<br />
<br />
Call me insane and despite the advice given here I'm still interested in investigating moving batteries to the rear before I take this option off the table completely. What is the criteria for wire sizing to the batteries? I assume charging current inflow would be one and outflow would be the other. Outflow in particular is probably uses specific to some degree. The 1000W inverter assuming 100% efficiency would / could pull 83A I think so this might be the minimum? <br />
<br />
Anyone got a (recent) wiring diagram with wire sizes used by Airstream?<br />
<br />
Thanks for humoring me....interesting topic.<br/>

I tow with a Diesel GL350/Safari 30 Bunk/ProPride. Two years ago i wanted to beef up my Solar and Battery bank and I installed two large Lifeline 6v batteries (159lbs each!), but relocated them to aft the axles. For my trailer this resulted in a reduction of at least 22' of large guage wire as my batteries are only a couple of feet from converter now. All good advantages, really happy with batteries indoors as well.

[Mike S.]

I wieghed the tongue wieght of my 27fb international and it was 1042 lbs. This was with the trailer completely unloaded, as it came from dealer. Full propane tanks, and @4 gallons of water in fresh tank. Actually it was jack wieght, but close enough.

[KJRitchie]

Originally Posted by Ohiobrits

Looking for other ideas to reduce hitch weight, I had a look at the Airstream Europe website. They have 5 models ranging from a 22ft 4000lb TT to a 27ft model that weighs in at about 6000lbs. They have 2, smaller propane bottles mounted on the A frame tight up against the front wall. It looks like the batteries are probably mounted inside the TT. MAX, not to exceed, hitch weight is 331lbs for all of them which works out between 4 and 6% hitch weight. Based on our convention to not go below 10% or suffer sway issues, these TT should all have major stability issues but that sounds like a topic for another forum.....

Smaller tow vehicles are the norm in Europe so Airstram adjusts. They use different hitch systems in Europe.

Until the U.S. auto industry downsizes there will be no stimulus for AS to change their US designs.

Too bad you can't buy a Euopean model. Doesn't AS manufacture the European models in JC and ship them overseas?

Kelvin

[TinTin]

Originally Posted by KJRitchie

Too bad you can't buy a Euopean model. Doesn't AS manufacture the European models in JC and ship them overseas?

Kelvin

Pretty sure they do. I believe the tour guide pointed out some European models parked outside the JC factory after our tour this spring.

[SteveSueMac]

I think I saw one - aren't they 7' 6"?

[idroba]

Originally Posted by Ohiobrits

Looking for other ideas to reduce hitch weight, I had a look at the Airstream Europe website. They have 5 models ranging from a 22ft 4000lb TT to a 27ft model that weighs in at about 6000lbs. They have 2, smaller propane bottles mounted on the A frame tight up against the front wall. It looks like the batteries are probably mounted inside the TT. MAX, not to exceed, hitch weight is 331lbs for all of them which works out between 4 and 6% hitch weight. Based on our convention to not go below 10% or suffer sway issues, these TT should all have major stability issues but that sounds like a topic for another forum.....

Anyone want to give 4% hitch weight a whirl and report back?

I have a copy of the european AS manual, all 150 pages of it (PDF format). I wish I could give you a link to it, but I no longer have the reference which was posted here on the forum about a year ago.

The manual goes into great detail about what they call "snaking" which we call sway. For some reason Europe does not even allow weight distribution hitches, so the tongue weights are very low, and thus all of the information on "snaking" and how to control it. They make a very big deal of "snaking" issues as well they might. They make a huge issue of loading the trailer and where weight is put. They have very small water and holding tanks to keep not only the weight down, but so empty or full they make little difference in the tongue weight, so the trailers don't go unstable.

When I read the manual, I am very thankful that we don't have such unstable Airstreams with very low hitch weights sold in this country.

Do not assume that the European Airstreams have solved the issue of sway control. They have not, and that is made very clear in the European Airstream manual.

[SSquared]

Originally Posted by Ohiobrits

Looking for other ideas to reduce hitch weight, I had a look at the Airstream Europe website. They have 5 models ranging from a 22ft 4000lb TT to a 27ft model that weighs in at about 6000lbs. They have 2, smaller propane bottles mounted on the A frame tight up against the front wall. It looks like the batteries are probably mounted inside the TT. MAX, not to exceed, hitch weight is 331lbs for all of them which works out between 4 and 6% hitch weight. Based on our convention to not go below 10% or suffer sway issues, these TT should all have major stability issues but that sounds like a topic for another forum.....

European countries have low speed limits for towing trailers. I have not seen an authoritative reference for this, but 80 KPH for heavy (over 750KG; 1650 pounds) seems to be the rule. That's about 50MPH. That significantly reduces sway.

[jcl]

Originally Posted by SSquared

European countries have low speed limits for towing trailers. I have not seen an authoritative reference for this, but 80 KPH for heavy (over 750KG; 1650 pounds) seems to be the rule. That's about 50MPH. That significantly reduces sway.

In the UK, that was the upper limit on single carriageway (non-divided) roads when we lived there. Dual carriageways (divided two lane) and motorways had a towing limit of 60 mph.

[Andrew T]

Not only are weight distribution hitches not used in Europe they are not legal in several countries.

To add insult to injury they also do not allow Electric Brakes so they have surge brakes usually actuated by cables or rods. This means that when your trailer does start to snake you can't just apply the trailer brakes to straighten it out.

It is funny with all their advanced cars their trailers have brakes like a model A Ford.

Andrew T

[Ohiobrits]

Originally Posted by Mike S.

I wieghed the tongue wieght of my 27fb international and it was 1042 lbs. This was with the trailer completely unloaded, as it came from dealer. Full propane tanks, and @4 gallons of water in fresh tank. Actually it was jack wieght, but close enough.

Note that Airstream will provide the as weighed factory weights including tongue if you provide the VIN. Contact them on the website using the "Company/FAQ's" section on their homepage indicating you need to know the weight before buying. The model I have bought had a catalogue tongue of 770 lbs (27FB International) and an as built, per Airstream, of 844 lbs with 60 lbs of propane. It has the second AC and a few other options so was expected to be slightly heavier. The second AC is supposed to add 52 lbs to the tongue so this is close to the as weighed 844 lbs considering there are a few other options also.

I pick it up next Friday and will weigh it. I'll be interested to see what weight I get.

[tjdonahoe]

You can look up the European models and it gives the tongue weights, you will find they are very light. These trailers aren't made to be pulled the miles we put on them ...the cables or rods do apply the brakes when or if the trailer starts to sway