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Old 02-13-2004, 12:51 PM   #1
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Question Layout questions 25B, 25C Tanks & Ballasting

My wife and I are kicking around with buying a 25' airstream.

I am leaning toward the 25B with the double/queen bed as opposed to the six sleeper as my tow vehicle has more than enough GCW rating, but I am thin on the GVWR of the truck... Adding the Hensley that I have in the garage won't help the TV weight distribution much.

What are the tank fresh/grey/black layouts in the 25B vs 25C (six sleeper). I am thinking that with the B (with both Grey and fresh tanks aft of the axle, if I heard right) one could remove some tongue load by "ballasting" the load. Most of the storage in the 25's appears to be forward of the axles, and I don't want to put anything heavy up high to keep it aft.

Also, Airstream just had to put the two batteries in the box on the tongue as opposed to in a box in the aft corner like on the 1960's vintage AS's.

Dry hitch weight of a 25B is 680 Lbs on a 6300 GVWR trailer (10.8 % of GVWR) , vs 750 for a 25C with the same GVWR or (11.9 %)

I am looking at leaving the 155 Lb canopy off my truck if I get the 6 sleeper to stay under GVWR of the truck!

Would like layout info and advice from those with both the 25 B and C models.

Thanks,
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Old 02-13-2004, 01:02 PM   #2
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You can see the tank and specs here:

http://www.airstream.com/product_lin...fari_spec.html


You can see the layout of the floorplans here:

http://www.airstream.com/product_lin...ari_plans.html


If you want to see where the tanks are installed in the chassis check out here:

www.silvertwinkie.org

I have the 25 C and love it. Some folks don't like the side bed, but we do.

Weight bars regardless of who made them will take some of the hitch weight off the rear of the tow vehicle and place approx 33% across the axles (this figure was in both Airstream owner's manuals that I had for both the Bambi and the Safari).

I would always try to keep the grey and black tanks as empty as possible when towing. Even though the fresh and part of the grey are right above and/or near the axles.

As for both batteries in a box on the a frame, I like it there. It's easy to get to and to remove and replace the batteries.

....and by the way......I'm towing the 25' C with a V-8 body on frame sedan.
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Old 02-13-2004, 01:46 PM   #3
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I am towing in the Pacific Northwest. We have steep mountains out here. I am also a mechanical engineer working on aircraft wing structures where weight is critical.

I know the floor plans. Pictures of factory tour do not help, because one needs to know what body is going on the frame. Pictures of tanks shown in link are on a 3 axle set-up, my guess is a 34 footer. Airstream owners manuals on line are not much help as they are mostly schematics. Also two Airstream dealers have told me that airstream has periodically changed tank locations around.

Different models have tanks in different places.

25 C has 19 gal black tank in back under the loo, grey most likely aft of axle, fresh water tank?

25 B has fresh tank (39 gal) under the bed, grey tank (39 gal) aft of axle and black tank (33 gal) forward of the axle due to center bath.

1969-70's Airstreams had rear bath, black tank under one corner, grey tank under the other corner (post 74) and a fresh tank under the gaucho in the front, or under the curbside dinette seat in those with front dinette.
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Old 02-13-2004, 03:59 PM   #4
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Not at all. The pictures you looked at of the frame with the tanks were that of a 25' Safari with a dual axle system. Look closely. The tanks are in a similar config...if I recall correctly the chassis you looked at on my website is that of a 25C just before the shell was lowered onto it. If you look at the pictures you'll actually see the shell mated to that chassis and I can 100% assure you that was not a tri axle 34' unit without question.

Tanks on the 25C have been in the same location for some time. I am unsure of the other Safari models.

Agreed that the mountains are an issue, however, hitch weight is not going to be your problem most likely, particularly if you use a weght distribution system and your only hitch weight range is between that of the 25 C of 750lbs vs. 680lbs of the 25 B. I can't believe that 70lbs would make that much of a difference if the tow vehicle has what I think you are suggesting it has...... I was not referring the owner's manual for you to read, I was stating that the factory claims a 33% distribution weight of the hitch weight when you use a good weight distribution system.

I don't believe you are correct about the fresh tank in the back. Airstream has made a strong effort to place objects of greater weights near or above the axle systems as the area around the axles if you look closey has extra framework around the area. You can see a side view of a 25' B here and will see the fresh water fill inlet right by the dual axles:

http://www.colonialairstream.com/new...6920.html#6920

I am unsure if your info on the location of the black and grey is right or wrong, so I'll take your word for that part.

You hit it right on with the tank configs on the 25 C and you can see part of the layout on the link I shared with you. The fresh if you look at the picture is directly in the axle area on the 25 C and most from what I've seen is in the exact same spot on the 25 B. I very much doubt though that Airstream would place the fresh tank that far back given all the frame seperation issues it had in the past (I mean without the HWH, the fresh alone back there would be 335.4lbs.) not a smart move in my book. In the pictures if you look the 25' Safari line does not seem to have the framework to support the fresh tank that far back. You can clearly see in the photo the frame reinforcement near the axles and how it goes away the further south you go of the axles into just a standard frame. You don't need an engineering degree to figure that one out! Just to be sure I'd ask Airstream or a dealer.
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Old 02-13-2004, 05:49 PM   #5
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The last time I asked a technical question like this was about Christmas, got the canned we're looking at it and will get back to you. Nothing since, check my lycos account daily.

I support in-service aircraft for repairs, I have to answer quickly... down time on my airplane is measured in $250,000+ lost revenue per day.


The 25 C if I remember has a 19 gal black tank under the rear, smaller due to location at back and location of dump valve at left rear, same tank as bambi and 22' safari.

If the 25C has the black tank all the way aft like I am assuming from pictures on your site, then fresh tank is the lighter one FWD of the axles, the grey tank is the large one aft of the axle with the 3 ports for bath sink kitchen sink and vent.

If the C can handle the weight of the bathroom walls and 19 gal tank at the end, then does it stand to reason that on a 25B with the black and grey tanks centered about the axle could have a 39 gallon tank mounted on centerline, under the forward portion of the queen bed at 1/2 the distance to the axles as the 19 gal tank and bathroom structure as the C?

Also, per the owners manual on the B, see the airstream site, for the 25B the water pump is in the curbside closet under a trap door in the floor, in which case having the tank above the pump makes since so pump does not run dry?

As to weight bars, I have reviewed data from several posters both on this sight and on the open roads forum. From all numbers run to date, I conclude the following:

1) 90% of tongue weight stays on the tow vehicle... weight is redistributed from rear axle to fron axle by cranking on the weight bars, but ...

2) Only about 10% of the tongue load is shifted to the trailer axles.

This has shown true using numbers from pick-up truxcks with 22' AS's to suburbans with 25's to bigger trucks like F-250 and 350 with large trailers (over 30'). I've crunched the numbers using CAT scale data supplied by other board members.

That is why I have an extra 2000Lbs of GCVWR but am at or near the line with the dry tongue load on my tow vehicle GVWR (due to weight of options, people, fuel and vehicle). Like I say, I've been crunching real numbers for awhile.
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Old 02-13-2004, 06:57 PM   #6
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I gotta take these one at a time here..

Quote:
Originally posted by pneum0
"The last time I asked a technical question like this was about Christmas, got the canned we're looking at it and will get back to you. Nothing since, check my lycos account daily."

I'll PM you a contact at Airstream. I have been beyond pleased with my exp with the factory. I have no doubts that a dealer might not respond in a timely manner. I had other issues here in Illinois with our "dealer".

"I support in-service aircraft for repairs, I have to answer quickly... down time on my airplane is measured in $250,000+ lost revenue per day."

I hear ya.


"The 25 C if I remember has a 19 gal black tank under the rear, smaller due to location at back and location of dump valve at left rear, same tank as bambi and 22' safari."

18 gallons is what the 19' Bambi and Safari C and 30' have. I agree 110% that the reason for this is due to the fact that it is further aft.


"If the 25C has the black tank all the way aft like I am assuming from pictures on your site, then fresh tank is the lighter one FWD of the axles, the grey tank is the large one aft of the axle with the 3 ports for bath sink kitchen sink and vent."

I'd agree here. I believe you are right.



"If the C can handle the weight of the bathroom walls and 19 gal tank at the end, then does it stand to reason that on a 25B with the black and grey tanks centered about the axle could have a 39 gallon tank mounted on centerline, under the forward portion of the queen bed at 1/2 the distance to the axles as the 19 gal tank and bathroom structure as the C?"

I am sure anything is possible, however like GM, I figure they try to standarize as much as possible.... as you well know, it keeps costs down. My money would be that the fresh tank is in the same position on the "B" as the "C" as it not only takes less time to build, but saves money as they don't have several different flavors of frame design and mount.

To answer the first part last, the shell weight is evenly distributed, so the weight issue of the shell on the rear is not really an issue. The tank however, even if you look at the 30' Safari also has an 18 gallon tank. Not working for Airstream I would guess this is due mostly to the fact that the rear end cannot hold a bunch of weight, particularly when traveling as base weights and stresses as you know can fluctuate in transit.


"Also, per the owners manual on the B, see the airstream site, for the 25B the water pump is in the curbside closet under a trap door in the floor, in which case having the tank above the pump makes since so pump does not run dry?"

Maybe, but it can still run dry if the tank goes empty. The 25C has the pump in a similar location however, the panel is also under the closet, but it is not under the floor. It is possible that the 25B has it under the floor, but again, I'd find it hard to fathom Airstream having several different designs for similar length coaches as it takes more time which in turn takes more money and profit is what they are looking for with quailty as well.


"As to weight bars, I have reviewed data from several posters both on this sight and on the open roads forum. From all numbers run to date, I conclude the following:

1) 90% of tongue weight stays on the tow vehicle... weight is redistributed from rear axle to fron axle by cranking on the weight bars, but ...

2) Only about 10% of the tongue load is shifted to the trailer axles."

Though this might be true about the amount of weight on the coaches axles, I will tell you first hand that the weight on my cars behind is diminished MOST significantly when the weight bars are on. Given the movement with cargo coils, I would say that an easy bet is that it's more than 10%. This was the case with the 460lb hitch weight of the Bambi and is beyond the case with the Safari. Additionally, the front of the tow vehicle gets a taste of the weight as well, so it's not limited to the rear of the tow vehicle and the coach.


"This has shown true using numbers from pick-up truxcks with 22' AS's to suburbans with 25's to bigger trucks like F-250 and 350 with large trailers (over 30'). I've crunched the numbers using CAT scale data supplied by other board members.

That is why I have an extra 2000Lbs of GCVWR but am at or near the line with the dry tongue load on my tow vehicle GVWR (due to weight of options, people, fuel and vehicle). Like I say, I've been crunching real numbers for awhile.
"

Here is where it becomes "Greek" to me based on you number crunching. Me, I took about a thousand different calculations based on GM's own numbers and where I thought I could improve it based on my knowledge of cars vs. trucks. I found in most cases, as RKM will say the tow ratings can be misleading. For example, a Chevy sedan with a similar engine and identical trans, will have a 5000lb tow rating compared to a 2000 Silverado 1500 which could have had a larger tow rating.

In the end, mods have proven that the car not only can do the added weight, but does it very well. I would use caution on other people's numbers and take the base info you get from the specs and make your own determination based on your own situation with a bit of help from what others have said.

Each person's data may vary as each circumstance is different.
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Old 02-14-2004, 04:59 PM   #7
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I hear you on trusting others data.

Problem with moding a vehicle is it does not change the sticker on the door post. It may be capable of moving and stopping the load but it won't keep you from getting pulled over at the scales for being overweight, or keep a lawyer from comming after you if you are involved in an accident.

There are two Airstream dealers in my state. Nearest one is 75 miles and $6,000 higher on a 25' coach than the dealer that is 300 miles away, who answers questions regularly. The guys 300 miles away will be setting up a test tow for me soon, and will be getting my business no matter what coach we end up buying.
The outfit close to home treated me like I was looking at a used car because we were not interested in the quarter of a million dollar class A they wanted to show us.
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Old 02-22-2004, 11:16 PM   #8
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Unhappy Got my answers from Jim at airstream tech.

On the 25 A and B the fresh tank is between the axles, the black tank is forward of the axles and the grey is furthest forward of them all. The front edge of the grey is almost even with the back edge of the front step.

So much for my idea of ballasting using the tanks.

They also said my idea for moving the batteries from the front box to a position next to the electical bus under the bed would void the warranty..

Time to see where I can shave some weight by other means or seek a slightly smaller trailer in the form of the 22' Safari....I just don't like the corner bed idea too much.
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Old 02-23-2004, 05:26 AM   #9
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Yea, some dealers are fairly worthless. That is interesting info on the tanks for the A and Bs. The 25C is similar in that it only has the fresh tank in the same place.

If the current lines are not going to work, have you considered a vintage unit? I think there you'd have the best of both worlds. No side bed and a larger coach.

The thing that bothered me the most about the 22' was that the dinette floor space was reduced by the streetside wheel well. The other thing that I didn't care for was the wet bath. Now where we go there are usually showers and/or lake, so the bathing part is pretty much covered, still the wet bath concept just didn't agree with us.

Eric
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Old 02-23-2004, 12:33 PM   #10
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Cool

I've looked at 7 Argosy's and about a half a dozen vintage airstreams...

Critters living in the basement, mass corrosion due to salt air environ + NW rain, and finally owners who costwise believe the old ones are made of gold even though the clearcoat has failed, the tongue is rusted and the belly pan is laying on the ground with something living back in there.

Have also had my share of nearly going through the floor next to the door. Looked at one on Vashon that had major floor mold... had been in desert SW and new owner had brought it to the NW without replacing seals, or covering.

I do however keep my eyes peeled for the gem in the rough.
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Old 03-24-2004, 10:15 AM   #11
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layout questions

Hey Pneumo- I've got a 25B and you have got the tank layout correct. When doing your calcs you seem to be using the 680 lb tongue wt that the factory uses. I'm not sure that is valid in all cases, if you go out at 5600 lbs gross wouldn't the tongue weight also drop? Even with full fresh water and a bunch of junk inside that's what ours usually goes out at. Also, you can shift the weight aft by 1) junking that silly mattress they supply and putting in a real queen size mattress ( you will need to extend the plywood platofrm and you will lose a little walkaround room) which will increase the weight in the rear by about 40 lbs, and if you want to get real trick, move the spare tire to the rear. In my biz the tongue weight issue would be called center of gravity, and moving 90 lbs ( mattress and tire) on an arm that long will really affect the cg. Finally, I have always wondered how AS could put "hitch wt 680 lbs (10%), gross weight 6300 lbs. And I thought I was bad at math.......
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Old 03-29-2004, 11:06 PM   #12
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Jack,

What biz you in?

I am a Stress Analyst on LARGE Commercial Transport Category aircraft.

CG shift means (in most cases) getting it aft of the axles. Tongue is point load on truck. Long moment arm forward of axle, short arm aft of axle. Framing aft, not as strong as beams forward. Most of the problem is moderen design. If you could put the refrigerator on or near the axle, and get that massive flex steel sofa off the front end... and the two 30Lb propane tanks and the two batteries.... Get my drift?

The wife and I have decided to put off our search for a year with her back in school and me busy at work and on our yard.

Thanks for "weighing in"

Mark W.
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