On a recent trip across New Mexico, we noticed a strange vibration as we towed our Airstream. We felt it while inside the truck when we towed at highway speeds, on straight as well as level pavement.
When we got to our first campsite, the interior of the trailer was more disordered than usual: baseball caps and sink covers were on the floor, and the mattresses had partially slid off the bed platforms.
In the past the Airstream had always towed like a cloud behind our Ford Ranger, smooth and nearly silent, so this was worrisome. I checked a few basic things like tire pressure (on both the truck and trailer) and the hitch at our next fuel stop, but found no obvious cause.
After a few hundred more miles of towing, one of the overhead cabinets began to sag—the result of some screws stripping out and rivets breaking—and we had a real crisis on our hands. (I fixed the overhead cabinet in the campground, and you can read about how I did that here.)
It was at this point that I knew a technical problem was lurking somewhere. The question was how to find it and fix it.
Our experience is not unusual
Often Airstreamers will post publicly online about repeated damage such as broken rivets and drawers falling out. Unfortunately, most of these people automatically assume that the problem is high tire pressure, or some sort of structural defect in the Airstream. But often, that is not the case.
Although lowering the tire pressure might help in some cases, there are many other reasons why you could be having trouble with rivets, cabinets, or other things breaking while you're towing.
Here are 6 possible causes to consider:
1. Maybe it's just a bad day
If you normally are able to pull into a campsite without a disheveled mess in the trailer, and then it happens once or twice, it's probably just the result of an especially rough road somewhere. Don't panic.
2. Have you checked the tires carefully?
Even if your tires aren't completely worn out, they could be "flat-spotted."
Long periods of storage can cause trailer tires to develop a flat spot where they've been in contact with the ground. This flat spot is probably not going to be visible, but if you see "checking" (fine cracks like those in the photo below) on the tires, that's a hint that there might also be a flat spot.
Turns out, flat spotting was the cause of our troubles across New Mexico.
The four tires all had flat spots from sitting for three months during the Tucson summer heat, and those spots never went away. This caused a significant vibration in the trailer that we could feel in the truck during towing.
The solution: new tires.
We switched to Michelin Defender LTX 235/75R15 tires which in my opinion are better quality that the original Goodyear tires. As bonus, they carry about the same load at 50 psi so the Airstream gets a softer ride.
3. When was the last time you balanced the trailer tires?
Like your car, the wheels and tires on your Airstream trailer need to be balanced, too. The tire shop did this when the tires were installed during manufacturing. But it's possible that a wheel weight has departed during your travels.
You don't need to take your Airstream to a service center for this–any tire shop can re-balance them for you. Or, you can look into installing dynamic balancers on your Airstream, like Centramatics.
4. Could it be the hitch?
Hitches are not one-size-fits-all.
In my early days of Airstreaming I didn't know this, and bought a hitch that was rated for 1,200 pounds of tongue weight. The problem was that at the time I owned a 1968 Airstream Caravel with only about 300 pounds of tongue weight.
The weight distribution bars on that hitch were so stiff that they didn't flex during towing as they should have. Every tiny bump and vibration was transmitted directly between the truck and the Caravel's frame.
The point is that if your hitch is rated for a significantly higher tongue weight than what you've got, it could be hard on the trailer.
Most modern Airstreams have a tongue weight of between 500 and 1,000 pounds. You can weigh your Airstream's tongue with a tongue scale, but since most people don't have access to a tongue scale, you can estimate the hitch weight at about 8-10% of the trailer's total weight. Check your hitch to see if it's in the ballpark for this tongue weight.
Tongue weight and weight distribution are safety issues that many Airstreamers are not fully aware of–especially newbies. This blog explains why understanding both could literally save your life.
5. When it comes to tires, heavier is not better
Make sure you're using tires that are rated to carry the weight of your loaded trailer, but don't subscribe to the theory that more is better. Overkill in tires can mean overly-stiff tires, causing problems such as broken interior rivets and tossing stuff around inside the trailer while towing.
I once knew an Airstreamer who had trouble with repeated tire failures. In response, he kept "upgrading" to tires with heavier construction. He figured that if a Load Range C wasn't good enough, he should go to Load Range D ... and Load Range E ... and eventually ended up with a set of very unusual Load Range G tires.
First off, this is nuts. Load Range G tires have low speed ratings (meaning highways speeds are a problem), and they're built like rolling rocks since they are meant to carry heavy truck loads.
Second, the concept of "load range" (and counting the number of tire "plies") is obsolete and misleading. These days tires come with a Load Index number that shows how many pounds of weight they are designed to carry. That's a far more relevant indicator, and it's something you should pay attention to when buying tires.
6. The worst case: floor rot
Airstream trailers made before model year 2021 have wood subfloors. Unattended water leaks (whether from rain or plumbing leak) will cause slow rot in the wood. Over time, this can cause the subfloor to be partially disconnected from the aluminum body of the trailer. This causes a host of problems, and one of the biggest symptoms is that rivets will start to break.
This is an especially common problem with vintage Airstreams. I've found rot in every vintage trailer I've ever owned. Here's what it looked like in one of them:
Floor rot can be easily diagnosed by a competent Airstream-specialist repair shop. The repairs are usually labor-intensive and expensive, as most or all of the interior will need to be removed to do a proper repair.
Fortunately, floor rot is not something you usually see in trailers less than five years old, unless they've been in an accident. It doesn't happen at all in model year 2021 and later trailers because they have rot-proof floors.
10 comments
Gil Jarvie
I thoroughly enjoyed the post, Rich, and will second the Centramatic recommendation for wheel balancing. I installed them on both my Globetrotter and towing vehicle and have been very pleased with their performance. I cannot confirm there is a correlation, but we have had very few popped rivets, interior or exterior, since adding them a year ago and nothing moves inside our GT, while traveling.
William McChesney
Thanks for this info – too stiff tires and too stiff hitch points well taken – I’m looking at getting a new weight distribution hitch and I would have thought a stiffer one would be better now I’ll be sure to keep it closer to the tongue weight – and I need to go and check the load rating of the tires.
Reza
Thanks for the great article! With regards to the new subfloors, what do you expect will happen when water eventually gets in from rain or damaged seals? Since the subfloor won’t rot, the owner can’t look for soft spots I assume and may further prolong fixing a leak if normal inspection is not done.
Rich Luhr
Reza: You don’t have to wait until floor rot sets in, to detect a water leak. That’s much too late and the damage is done.
There are usually clear signs that water is getting into the Airstream. Often it’s as obvious as water puddling on the floor.
We have published two blogs about how to find detect and fix water leaks. You can read them at the links below (or type “leaks” into the search bar on the AIR GEAR website):
https://www.airgear.store/blogs/airstream/water-leak-now-what
https://www.airgear.store/blogs/airstream/finding-and-fixing-rainwater-leaksJeff Curtis
The load distribution hitches from Weigh Safe measure your actual tongue weight and allow you to customize the pre-load on your anti sway bars with every tow. The Centramatic wheel balancers are super easy to install and the the technology is simple, foolproof, and amazing. I’ve considered putting them on my tow vehicle, too. Most people pump their tires up to 80 psi no matter what, but when you look at the load tables for your actual tires they might be fine with a lower pressure that would provide a smoother ride. I have two axles to distribute the load and could theoretically run my tires under 50 psi, but still run them at 70-75 psi in case of a blowout of one tire.
Rich Luhr
Jeff, thanks for your comments. We’ve also written about why someone might choose to run a higher tire pressure than is strictly necessary (basically explaining what you said, in greater detail) here:
https://www.airgear.store/blogs/airstream/whats-the-right-tire-pressure
Tom Rearick
You left out replacing shocks and axles on old Airstreams. The original shocks and rubber “springs” were useless in my 1989 Excella. Every trip ended with picking up stuff thrown out of drawers. That happens less now I replaced the shocks and axels.
Rich Luhr
Tom, good point. If your Airstream is more than 20 years old, the rubber in the original torsion axles have undoubtedly gotten stiff. The rubber can’t be replaced, so the correct action to take is to replace the axles. Colin Hyde Trailer Restoration specializes in replacement axles for precisely this reason.
James Heugel
The load index of the Michelin Defender (109) is significantly less than the Goodyear Endurance (117)
Rich Luhr
James H: You’re right about the Load Indexes. Let’s put them into perspective. A load index of 109 (Michelin Defender) means that each tire can carry 2,271 lbs. That’s a total weight of 9,084 lbs for a dual axle trailer, and 4,452 lbs for a single axle trailer.
The Goodyear Endurance has a load index of 2,833 lbs per tire, which means 11,332 lbs for a dual axle trailer, or 5,666 lbs for a single axle trailer. There are not many Airstreams that need that extra weight capacity, so for most people the higher load index of the Goodyear Endurance tires is moot.
A quick way to tell is to look at the GVWR (Gross Vehicle Weight Rating) for the trailer. This is the “don’t exceed” weight. If the GVWR is less than the tire capacity, you’re all set.
For example, my 2020 Globetrotter 23FB has a GVWR of 6,300 lbs. The four Michelin Defender tires can carry 9,084 lbs when inflated to their max pressure of 50 psi, so obviously we are well within the limits of the Michelin tires.