Single or double axles?

[dan_lemire]

Alright, I'm back hunting and decided to reduce the trailer lenght I was seeking from 30 to 26 feet. I need a big trailer since I am 6'4'' and have 3 children.

I am currently looking at vintage Overlander and found a '58 with a single axle. Most other I saw from the Sixties had double axles. What are the pros and cons of single VS double?

Thanks

Daniel

[ankornuta]

Originally Posted by dan_lemire

Alright, I'm back hunting and decided to reduce the trailer lenght I was seeking from 30 to 26 feet. I need a big trailer since I am 6'4'' and have 3 children.

I am currently looking at vintage Overlander and found a '58 with a single axle. Most other I saw from the Sixties had double axles. What are the pros and cons of single VS double?

Thanks

Daniel

In '58 tandem axles were only an option on the 26 footers, as I understand it. Personally, I think tandem axles are always going to be safer when you consider the amount of tread on the road in terms of safety. I think it also helps to balance a large trailer better.

Of course, that also increases your friction... I'd take decreased fuel economy over increased risk any day though...

Just my two cents...
-Andrew

[markdoane]

I have a single axle 24' Tradewind. I think one consideration in the single vs tandem argument is the weight of the trailer.

A 26 ft Overlander probably weighs around 4000#. Subtract 400# tongue weight and you have 3600# resting on the tires.

If you have a single axle, that is 1800# per tire, reasonable load for a load range D tire at reasonable inflation pressure.

On tandem axles, the weight on each tire would be 900#. You could adjust the inflation pressure for 900#, but the pressure would be so low that the tires would have very little lateral stability. In fact, I don't think you could run tires at that low pressure. So you would end up pumping the tires up to about twice their load capacity just to get enough sidewall stiffness. That would cause the trailer to ride 'hard'.

So my vote would be for a single axle.

[RDM16CCD]

This is a good topic- thanks for starting it.

I think another benefit of a single axle is it's easier to make a sharper turn when backing up. This has been my observation based on having a 21' (double) and a 16' (single) - but maybe it has more to do with the length? Has anyone else had this experience?

I like the thought that a double axle provides some safety margin in case of a tire blow out. I worry with my single axle that if I ever have that experience it will scare me so bad that I'll give up trailering. My plan is to replace the tires at least every 5 years, or when they're worn 50%. This will guard against aging-related failures, and will help somewhat with road hazard problems. But I'd still choose the double axle for the percieved safety margin.

Maybe the tire iindustry will someday come up with run-flat trailer tires (like some cars are starting to have) - this would be a great thing for us single axle folks!

[Jim Jarzabek]

Regular road use of a true vintage trailer neccesitates replacement of the original axle & leaf springs....
I would install 8 ply or heavier trailer tires - 7.00 x 15.00 Power Kings always work great for me & I have never had a flat. With a new axle and new tires you should be fine as long as you weigh your trailer separately from your tow vehicle on a scale (CAT scale is great at a truck stop) and don't exceed 80% of the single weight rating shown on the trailer tire sidewall (for both tires combined).

[85MH325]

The benefits of a tandem (or triple) axle is that the trailer rides more smoothly, and is more stable when it has the proper tires aired to the proper pressure. There is no 'bounce' that you sometimes see with a single axle trailer. They resist sway better as well. If you have a flat, you can remove the tire/wheel and continue at a slower speed until you can get it repaired without damaging the undercarriage. They also tend to back easier as they don't swing as quickly behind the tow vehicle.

The downside of a tandem (or triple) axle is that you have to buy more tires when it's time, and maintain more wheelbearings and brakes.

I don't necessarily agree with Jim that an old trailer with a leaf spring/solid axle "needs" an axle replacement. That's a decision that needs to be made individually from the condition of the equipment under the trailer. Many of them on the road are still fine, they just don't ride as well as a rubber torsion axle. I WILL say though, that most of the rubber torsion axles that are over twenty years old will need to be replaced, however.

Roger

[overlander63]

Having had and towed both, I can tell you that:
A single axle trailer will be more manueverable, maybe too much so while backing up.
A single axle trailer will tend to bounce more going down the road, transferring some of that bouncing to the tow vehicle.
A single axle trailer has its full weight on two tires, so if you have a problem with a tire, wheel, bearing, etc., you are done with your camping trip in that spot, until it is repaired.
Our single axle 20' coach weighed 3500 pounds in working order, with no supplies or personal gear on board.
Double axle coaches will tend to ride more smoothly, as the bouncing of the axles will tend to cancel each other out.
Double axle coaches are less likely to sway while towing, and will resist turning while backing up (both plusses to me).
if you have a tire, or brake problem, you can take a tire off a tandem axle coach and limp in to town for repair.
Our 26' coach weighs a tad over 5000 pounds in working order, without our personal gear on board.
The tongue weight of the 20' coach was 410 pounds, leaving 3090 pounds for the tires to carry, or 1545 each.
The tongue weight of the 26' coach is 570 pounds, leaving 4430 pounds for the tires, or 1107 pounds per tire.
UP through the early 60's, the shortest coach I have seen with tandem axles was 25'. I did see a 1968 tandem axle Safari, at 22' the shortest tandem axle Airstream I have seen.

[air19]

We are starting a complete renovation of a '53 Flying Cloud which has a factory dry weight of 2540 lbs for this 22 footer.

The single axle gives us two advantages in this renovation: 1) we save a couple hundred pounds from the weight of the second axle/wheels/tires; 2) we save a lot of space on the inside with much smaller wheel wells. This gave us more layout options than the traditional twin beds in the middle.

We know we are making a major sacrifice in terms of safety regarding a tire blowout, but our ultimate goal is to design the lightest weight Airstream possible for this 22' length.

- Mike

[bryanl]

The single axle overlander is a bit lighter overall than the double axle yet has a higher hitch weight than the double axle version.

The manuverability I think is due more to the length of the trailer and the ball to axle distance than to number of axles. This also influences the sway tendencies.

The redunancy factor or being able to limp when one tire is gone is an issue but the risk of such a problem is fairly small. There are those who say a single has less risk than dual because, on a dual, the front tire can kick up hazards for the rear. The fact is that with good tires and maintenance, the risk of failure is low.

Scuffing the tires is a factor but TT tires are made with this in mind. Again, a minor to insignificant factor because it is only an issue in extreme maneauvers.

The bouncy ride I can see as bumps influence the only support on one side. I would think the suspension would take care of most of this and roads where it is a concern would have other hazards to worry about.

I do remember some fulltimers who towed a single axle early sixties overlander behind a sedan for many miles without any special hitching. Their experience, even letting teenage grandkids drive, was a pleasant one.

[mandolindave]

The single axle trailers seem easier to level side to side. I guess that wouldn't be an issue if you stay at flat campgrounds, but I don't. Tandem axles would come in handy when it comes time to changing tires though.

[Paul Mayeux]

Yes, this is a good thread. When I purchased my 54 Cruiser (26') I was a little leary of the single axle. Since I knew going in that I was going to do a shell off restoration I toyed with the idea of adding a axle. I talked to David Tidmore, who is the manager of our local Airstream dealer, and he said that someone at Airstream had made the comment once that they would still be using single axles on coaches up to 25' but that there is the perception factor that more is better. The single axle coaches back then did not give any more trouble than the tandem models. I also couldn't find any discussion on this forum that people with single axles were having towing or safety issues. The key is attention to tires,loading and maintenance. I ended up staying with a single axle, however I replaced it with a new torsion style with a 5,000 lb rating per Inland Andy's advice. I figured a torsion axle would add a little more cushion than the leaf spring set up. For tires I went with the Marathon 225-75-15 LR D which gave much more capacity and a softer ride than the original 700-15 LR D.

[Silvertwinkie]

Having had both, I can tell you that the dual axle does not bounce as much as the single...and in the event I get a flat an need to limp off the highway, the other three wheels can help me do that, particularly if the coach you are looking at also as torsion axles.

Eitherway though, your '97 Land Rover Disco towing 26' is not gonna be a good idea.