Axle Rating

[wkerfoot]

IIRC - If I recall correctly.

Bill

[SmokelessJoe]

Looking more deeply into this I now realize that we did not get the trailer weight so much as we got the weight on the axles.

We weighed the trailer on the local farm scales while it was attached to the tow vehicle.

That would have given weight on the axles more than it would have given the actual weight of the trailer.

These forums are wonderful for sharing and learning.

Thanks.

Sergei

[Anon]

Originally Posted by SmokelessJoe

The WEIGHT per foot of Airstreams also steadily increased over the years

Sergei

Hence the reason axle ratings increased.
My Minuet weighs about 1500 pounds less than a comparably equipped new Bambi. Both are the same exact length, 19'3".

[downtime]

I've got a 61 Bambi and it needs a new axle. I also want to down grade my tow vehicle from a Yukon v8 to a Jeep Wrangler 6. The Yukon has no problem stopping the trailer w/o brakes, but I know the Jeep will unless the new axle system is put together correctly.
The previous owner pulled it for years with a Datsun 4 cyl. Pick up.

I would like some facts or opinons on the following:
... is there 13 tire, axle, brake system combination that is considered 'safe' or 'advisable' in todays market?
... if there is not and we must go to a 14" how do we make it work on a 61 where there is hardly enough room to get a 13" off and on? (low profile?)
... if you know of a safe T,A,B combination, can it move easily from one to another tow vehicle?

[85MH325]

Originally Posted by pattersontoo

Hence the reason axle ratings increased.
My Minuet weighs about 1500 pounds less than a comparably equipped new Bambi. Both are the same exact length, 19'3".

Actually, Lou, if you weighed them, you'll probably find a significant weight difference even between your '73 Argosy 20 and your '77 Minuet. By the late '70s Argosy was really trying some innovative things to lighten the trailers: the bonded aluminum sandwich flooring and all aluminum furniture frames rather than wood. Somewhere in the dark recesses of what is left of my mind, I also seem to remember that the Minuets were narrower than the original Argosy 20 as well? That 6" or so of width loss would also shave a bunch of pounds.

The Minuets were probably the last real attempt by Airstream to produce an ultra-lightweight trailer. I can't think of anything they've done since then that would be considered an ultralight.

Roger

[85MH325]

Originally Posted by downtime

I've got a 61 Bambi and it needs a new axle. I also want to down grade my tow vehicle from a Yukon v8 to a Jeep Wrangler 6. The Yukon has no problem stopping the trailer w/o brakes, but I know the Jeep will unless the new axle system is put together correctly.
The previous owner pulled it for years with a Datsun 4 cyl. Pick up.

I would like some facts or opinons on the following:
... is there 13 tire, axle, brake system combination that is considered 'safe' or 'advisable' in todays market?
... if there is not and we must go to a 14" how do we make it work on a 61 where there is hardly enough room to get a 13" off and on? (low profile?)
... if you know of a safe T,A,B combination, can it move easily from one to another tow vehicle?

IMHO, towing ANYTHING with a Wrangler is an accident waiting to happen... and this from a long-time Jeep affectionado. I towed a lightweight tent trailer with a CJ-7 and later an '81 Scrambler and wouldn't recommend it to anyone. The short wheelbases on Wranglers are the problem. When things happen while towing, they happen fast. When things happen when towing with a short wheelbase, you don't even have time to recognize that things have gone bad before you crash.

Once you replace the axle, the Bambi shouldn't be quite so "low profile" any more. Replacing the axle on my Burro raised the frame approximately 5" higher from the ground than it sat with the bad axle.

I towed my '61 Bambi with an '85 Toyota 4cyl auto long bed pickup. I only did it a couple of times, and only because it was what I had. It was an OK experience, but not a 'pleasant' one. I have towed a number of fiberglass RV's (most recently a Burro 17' widebody and a Scamp 16' Custom Deluxe, both in the Bambi weight and size range) with a '94 Toyota extended cab 4WD auto 3.0l V6 pickup, and it just didn't have enough umph for towing against the wind in the flats of Iowa. The wheelbase was fine, but the 3.0l six wasn't up to it. I bought an '02 Tundra extended cab with the 3.4l. What a world of difference, BOTH in handling and power while towing.

Back to your question, I had load range "C" rated 13's on new wheels on my new Dexter axle under the Burro and it performed admirably. The trailers typically came with "B" rated 13's. I think as long as you stay with "C" rated 185 80R 13 tires, you'll be OK weight rating wise for your Bambi. Marathons are rated at 1480 per tire. Your Bambi should weigh in the range of 2400-2500 lbs loaded, and the combined rating of the "C" rated Marathons is 2960, well under their weight range.

Roger

[downtime]

Good thought.. I'll scratch the Wrangler.... Thanks

[Anon]

Weight difference between the 1973 and the 1977 is close to 400 pounds. Had to weigh them for the license plates. The state of Michigan wants as much money as they can get out of us so they have moved to the "weight/fee" method for plates.
The Minuet is 8 inches narrower than the Argosy 20. Most of the interior in the Argosy 20 is aluminum too.
The Minuet was a wonderful idea; at least to me. It pulls better than any of the three Airstream products I have owned. After the axle replacement, it floats like it is brand new! I wish Airstream would attempt something like the Minuet again. They would sell like hotcakes nowadays!
I do believe that Airstream has become much heavier than Wally had ever imagined them being.
The point being that the axle weights went up because the overall trailer weights went up.
I kept the original weight rating for my axle. I am not sure if there is any truth to it but I have heard of an Airstream trailer that had an axle with a larger weight rating installed and it nearly shook the trailer apart on its first trip. The dealer that installed it was sued by the owners. I figure that the original axle rating should be close enough to being what is best for the trailer. I do not think Airstream "under-rated" their axles. That would not be safe.

Originally Posted by 85MH325

Actually, Lou, if you weighed them, you'll probably find a significant weight difference even between your '73 Argosy 20 and your '77 Minuet. By the late '70s Argosy was really trying some innovative things to lighten the trailers: the bonded aluminum sandwich flooring and all aluminum furniture frames rather than wood. Somewhere in the dark recesses of what is left of my mind, I also seem to remember that the Minuets were narrower than the original Argosy 20 as well? That 6" or so of width loss would also shave a bunch of pounds.

The Minuets were probably the last real attempt by Airstream to produce an ultra-lightweight trailer. I can't think of anything they've done since then that would be considered an ultralight.

Roger

[Anon]

Originally Posted by downtime

I've got a 61 Bambi and it needs a new axle. I also want to down grade my tow vehicle from a Yukon v8 to a Jeep Wrangler 6. The Yukon has no problem stopping the trailer w/o brakes, but I know the Jeep will unless the new axle system is put together correctly.
The previous owner pulled it for years with a Datsun 4 cyl. Pick up.

If you had the 4.0L inline six you would have enough power to pull but you would soon regret the short wheelbase of the Wrangler.
The Wrangler would back the trailer up nicely but the towing would be monstrous.
A good rule of thumb is the longer the wheelbase, the better the tow vehicle and trailer will handle on the road.

[overlander63]

Originally Posted by pattersontoo

I do not think Airstream "under-rated" their axles. That would not be safe.

Lou, way back in the "olden days of yore", Detroit would max out the tires' capacity to have the car ride softer. This would work until the unsuspecting motorist would load up his family, and 2 weeks' worth of supplies, and head out on vacation. This would sometimes end in a serious blowout/ accident, with often disastrous results. While I don't think Airstream ever knowingly did this, it is possible the tires were given a higher capacity rating by their manufacturers than they were capable of providing, and when the flaw was discovered, there was no way to correct the deficiency without going to larger tires.
If anyone wants to read about the overloaded auto tire issue, you can pick up a copy of the book, "Unsafe At Any Speed", by Raph Nader. The book is probably long out of print, but you may be able to find a copy at your local library.

[axleman]

Originally Posted by pattersontoo

I am not sure if there is any truth to it but I have heard of an Airstream trailer that had an axle with a larger weight rating installed and it nearly shook the trailer apart on its first trip. The dealer that installed it was sued by the owners. I figure that the original axle rating should be close enough to being what is best for the trailer. I do not think Airstream "under-rated" their axles. That would not be safe.

Lou,

It is true – as I have heard the same thing – right from the horse’s mouth. Maybe not the same horse – but the exact same situation. I can say with 100% certainty, larger axle ratings (or too much axle) will wreck an Airstream trailer.

Here’s the story as I recall: I got a call one day, when I used to sell axles for a living, from a fellow discussing just that. He had a dealer install an axle (the dealer specified the axle manufacturer and rating and said he was an expert) that was "too much" for his trailer - the results were disastrous!

He started the conversation, with me, by asking what I would recommend as an axle manufacturer – we discussed his trailer specifically and as I recall I suggested 3500-3700#! He then asked if I would "put that in writing". When I asked why? He said that Dexter and Al Ko had said the same thing - but he needed something in writing to take to court for his lawsuit - against the dealer that had installed the 5000# axle (or maybe 5200#) and ruined his Airstream by literally rattling it apart. I obviously felt bad but wanted nothing to do with a lawsuit.

Custom axle manufacturers (the majority) will build any axle that you, the customer, order – in any capacity that you, as a customer, request. The customer is always right! It is the axle manufacturers job to build the axle properly and stand behind it 100%. However it is the customer’s job to order the proper axle for their individual needs. In the case above “the expert dealer” was not an axle manufacturer – they sold axles and in this case the customer relied on “the expert” and ruined a trailer.

My “words of wisdom” – do your own research – read the forums – talk to others that have done it – use caution in selecting an axle. What should have been a great experience for this customer was anything but. No axle manufacturer wants to ruin a trailer, nor does the customer – research, research and then research some more, prior to ordering your axle and look out for “experts” – they scare me!

Regards,
Henry

[85MH325]

While it's true that too heavy rated of an axle can damage a trailer, this, of course, begs the question "how much is too much?" How do you know how much is enough and when do you exceed it?

I increased the axle rating on my Burro by 1500 lbs from a 2000 lb #9 to a 3500 lb #10, and towed it for thousands of miles. I improved the handling and ride 100%, and didn't damage anything, nor did I jar or shake anything loose. The folks who bought the Burro have towed it many thousands of miles more and are delighted with it.

Regarding the rumored lawsuit, one can sue anyone for anything... it doesn't mean you'll succeed. There are lots of things that "will shake an Airstream trailer apart" including significantly out of balance running gear, a worn out axle, and a tow vehicle that has suspension too stiff for the trailer; I'm not saying that's not the case, but it's a long road to proving damages.

I think that there is a lot of leeway here in selecting the 'right' axle for an application. The factors that come into play in axle selection are, of course, the actual dry weight of the trailer, the anticipated 'wet' weight, and the number of axles, the weight rating of the stock axles, and their actual service life.

If you consider that a torsion axle should have an approximate 20 year service life, and you only got 12 out of it, it's probably rated too light. If you got the 20 years, it's probably about right, and it if lasted 30 and you have popped rivets, it may have been too heavy to start with. I have seen many factory-stock axle examples of all three cases over the years on a variety of brands of trailers.

It appears that for many years axle selection by manufacturers was sort of "best guess" when it came to actually calculating what the cargo loading capacity of any given trailer should or could be above the trailer's dry weight (and varied with options, of course). It's interesting to look at the longer Airstreams and the GVWR and axle ratings. Most of them on the road appear (from folks who have submitted their "travel weights" here) to be overloaded with just an average cargo load. I am always concerned about the GWVR on my 34' as the GVWR is less than a thousand pounds from the trailer's stated dry weight. When you consider that I have LOTS of HEAVY installed options, my guess is that merely filling the tanks probably puts the trailer over its GVWR (although I haven't weighed it at all).

"Engineering" in the old days was done by best guess from experience. Frames were built just heavy enough not to break. When they did, manufacturers built that area heavier. The era of CAD/CAM only allowed us to refine our ability to make unrepairable mistakes. There is an entire line of high-end motorhomes that have chassis that break and are unrepairable because of their design. Lawsuits are flying on that one... and it's across their entire product line!

So, back on point, a replacement axle of 5,000 lbs GVWR under an early '60s Bambi, Caravel, or GT would probably be too heavy, but a 3500 lb axle may work just fine. A 5000 lb may be just right for an early '70s Safari or Caravel, but the 3500 lb would probably be underrated. All this again depends on installed options and dry/wet weights as equipped.

There are lots and lots of variables to consider. To confuse it even more, some bearing lube options are only available on specific lug pattern brake drums and that may be an issue in replacement axle selection.

I would also suggest that anyone contemplating an axle replacement investigate all of these options independently and have a good idea what your options are before contacting ANY dealer to have the work done. This stuff isn't rocket science, but there are enough options that it takes a while to wade through the information to determine what's appropriate for YOUR application. This is truly one area where blanket statements just don't apply. Each trailer has to be evaluated for it's specfic needs when it comes to replacing axles.

Roger

[axleman]

Roger,

Well said sir.

I think that we are both pointing out the same thing - a customer needs to do research prior to any axle purchase.

Lots of options, prices, features to review - depending on the manufacturer!

Additionally, as a retired axle vendor, I can tell you first hand - most (not all) folks know little about an axle.

These forums are a great resource from which to gain a bit of axle education!

Happy Holidays,
Henry

[uwe]

Originally Posted by 85MH325

While it's true that too heavy rated of an axle can damage a trailer, this, of course, begs the question "how much is too much?" How do you know how much is enough and when do you exceed it?

I can tell you from experience that a 1800lb increase in axle rating is too much for a seventies TradeWind. I had 3500lb alxes instead of 2600lb axles under it for a short while ( not by choice, btw.), and it was terrible. Actually as bad if not worse than the old axles were. Safer, perhaps, but not smooth at all. Changing to 3000lb axles ( an 800lb combined upgrade for the tandem) was great. The trailer then rode most excellent.
I can also tell you from experience that a single axle uprates smoother than a tandem. Putting a 5500lb axle under a 68 Safari seems just right.
Then, I can attest to the fact that not all axles are rated reliably. Some manufacturers do ballpark ratings, which becomes evident when you mount the assemblies and the supposedly properly rated axles sag to their knees immediately.
My advice would be to go with a good and well known name brand such as Dexter or Henschen. The others simply do not measure up to the quality and precision that you and your Airstream deserve.